Exoplanet Update!!

An artist’s impression of an exoplanetary system as seen from the surface of an exomoon. Image credit: IAU/L. Calçada.

The last time I discussed exoplanets in this blog was in 2017 with my essay ‘Exoplanets Galore‘, but I think we can all agree that a lot has happened since then!

Here’s the bottom line by March 2023 if you don’t want to read further.

Total exoplanets: 5,312 confirmed out of 9,343 candidates

Total in Habitable Zone: 214 exoplanets of all sizes

Total Earth Analogs: 23 the size of Earth in their Habitable Zones

Number of directly imaged exoplanets: About 30.

Number of atmospheres detected: 11 so far: Water, carbon dioxide, methane, hydrogen, helium and no biosignatures like oxygen, nitrogen.

Planets with magnetospheres: 1 so far: HAT-P-11b

Closest Earth Analog: Proxima Centauri b at 4.2 light years. (probably lifeless due to frequent flares from star). Gliese 1061 b, c,d at 12 light years. A planetary system with multiple Earth-sized candidates in HZ.

Closest Earth Analog around sun-like star: Kepler 452b, 1,400 light years from Earth orbiting G-type star. It is 5 times the mass of Earth and has twice the surface gravity. Probably between a terrestrial and Neptune-type surface with large ocean.

Searches in Progress: TESS was launched in 2018 and will operate until 2025. It will search the 200,000 brightest stars in the sky and hopefully find ‘thousands’ of new exoplanets using the transit method. So far it has found 6,386 candidates and 326 confirmed exoplanets. Gaia was launched in 2013 and will also last until 2025. So far, Gaia has found 18,383 candidates and has verified 73 exoplanets. Meanwhile there are over 43 ground-based major observatories with exoplanet detection programs mostly designed to verify candidates spotted by satellite studies.

Now let’s dig into the details!

According to NASA, by March 30, 2023 there are now 5,312 confirmed exoplanets, among 9,343 candidates, including 3,981 multiple-exoplanet ‘solar systems’. These confirmed exoplanets include 195 that are ‘terrestrial’ or Earth-sized, and 1,605 that are ‘super-Earths’ up to 5 times bigger than Earth. According to the European, Extrasolar Planet Encyclopedia (EPE) as of March 31, 2023 lists 5,346 exoplanets in 3,943 planetary systems, and 855 multi-planet systems.

The NASA catalog is searchable but very bare-bones. It only gives name, size and distance. The Extrasolar Planet Encyclopedia ( EPE), however is also searchable but in many more fields including the exoplanet’s radius, period and distance from its star.

First a bit of terminology.

Habitable Zone (HZ), also called the Goldilocks Zone, means the region surrounding a star where the temperature of an exposed surface with no atmosphere, is between the freezing point of water and the boiling point of water where life could supposedly exist. Of course you can’t have liquid water on a planet with no atmosphere, so these distances are lower limits. If the planet has a warming Greenhouse atmosphere dense enough for water to exist it can be farther from the star than these limits because the surface is warmed to a higher temperature. But it is a good first guess for the size of this zone without making any assumptions about atmospheric composition. By the way, Earth is right in the middle of our Sun’s HZ. Care has to be used in using this in the seach for life because even exoplanets that seem too cold to sustain liquid water could have liquid oceans under a thick icy crust like the moons of Jupiter.

Earth-sized means that the exoplanet is very close to our Earth in SIZE, meaning diameter, which means a radius of about 6,300 km. It also means that it can be found anywhere both inside and outside the HZ. Care has to be taken in using this as a search for life indicator because the moons of Jupiter-sized exoplanets can be Earth-sized like Titan in our own solar system, and tidal energy could keep their interiors warm enough for liquid water.

Earth-like means that the exoplanet is not only Earth-sized but inside its star’s HZ. These are also called Earth Analogs or Potentially Habitable Exoplanets.

Habitable Zone exoplanets

The very first thing that you or I would want to know is, how many of the 5,300+ exoplanets are in their HZs? Although a good estimate is about a few hundred, the exact answer is not as straight-forward as you might think.

Exoplanets are often found in elliptical orbits so some of these may only spend part of their ‘year’ in the HZ and most of their time too hot or too cold to support liquid water. To make matters worse, because stars evolve over time and become brighter, the HZs around every star start out close to the star when the star is young but slowly drift further away from the star as it ages. A planet formed inside the HZ may find itself outside the HZ as it gets older. In our solar system, Venus started out inside the HZ of the sun when it was formed 4.5 billion years ago, but now finds itself just inside the HZ today as a much hotter and inhospitable Earth-sized world. The range of distance during the entire lifetime of the star where HZ conditions exist is now called the Continuously Habitable Zone. Our Earth will leave this zone in another 7 billion years, while Mars will find itself in the comfortable middle of this zone by then.

Neither the NASA nor the EPE catalogs explicitly give statistics on this sub-category because the exact location of the HZ for each star depends on some assumptions including orbit shape, age of star, surface reflectivity, and Greenhous gas content. None of these ‘official’ catalogs wants to offer an official count because it could be ‘incorrect’ or worse-still, meaningless.

According to the Habitable Zone Gallery maintained by astronomers Stephen Kane and Dawn Gelino, their March 2023 catalog includes 4,628 exoplanets with known orbits. The figure below shows in green that only a total of 214 spend more than half their ‘year’ inside their star’s HZ. These include all types of exoplanets not just Earth-sized ones.

Image credit : HZGallery.org.

The Search for Earth Analogs.

How many exoplanets are both Earth-sized and in their star’s HZ? Depending on the details there are up to a few dozen that seem very promissing.

Encyclopedia Britanica says 40 as of March 2023. The searchable Habitable Exoplanets Catalog gives 23 Earth-sized and 39 super-Earths (3-10 times Earth mass) for a total of 62 habitable worlds by January 5, 2023. One graphical summary by Chester Harman gives 13 potentially habitable exoplanets as of March 2022 when stellar evolution is factored-in. So, lets take the charitable view and use the Habitable Exoplanets Catalog tally of 23 Earth-sized and 39 super-Earths.

The habitable zone for a range of stellar temperatures, showing Venus, Earth, Mars, and a selection of potentially habitable exoplanets. (image credit: Chester Harman)

Well first of all, the super-Earth exoplanets are problemtical because they are larger and more massive than Earth. They have a lower density so many astronomers suspect that these are Water Worlds. If you had placed Neptune in the sun’s HZ at the time of formation, instead of being a planet with a thick icy mantle on top of a rocky core the size of Earth, it would have had a thousand-kilometer-deep water ocean on top of a rocky Earth-sized core. You could have life in a deep ocean, of course, but with no solid surface on which life could emerge and evolve. It is hard to understand how ‘fish’ would have created telescopes or even known that the rest of the universe exists at all.

Some of these super-Earths closer to the size of our planet could have enormous oceans covering their surface but with diminishing land areas. For future explorers, these exoplanets would still be massive enough that we would never be able to visit the small islands on their surfaces and return to space because their escape velocities are so high.

The closest Earth Analogs.

We are obsessed with finding the closest because these would be the easiest targets for future interstellar probes to visit within a human lifespan of travel. The current catalog lists quite a few of these but they all orbit red dwarf stars. TheTRAPPIST-1 system contains TRAPPIST-1e, f and g — all located in the habitable zone of the star. The M8V red dwarf star is 39 light years from Earth. Unfortunately, different studies have come to different conclusions on whether any TRAPPIST-1 planet can retain substantial amounts of water. Because the planets are most-likely synchronized to their host star, water could become trapped on the planets’ night sides and would be unavailable to support life.

Meanwhile, Kepler 442b located 1,200light years from Earth is only 2-3 times the mass of Earth and is in the HZ around a K-type sun-like star. It has a temperature of 233 K (−40 °C; −40 °F) and a radius of 1.34 REarth. Because of its radius, it is likely to be a rocky planet with a solid surface. The mass of the exoplanet is estimated to be 2.36 MEarth. The surface gravity on Kepler-442b would be 30% stronger than Earth, assuming a rocky composition similar to that of Earth.

Based on the observations available by 2013, statistically, there should be nearly 9 billion habitable Earth-sized planets in our Milky Way. A 2020 estimate places this at about 6 billion exoplanets orbiting sun-like stars. A 2019 study places this at 10 billion habitable exoplanets orbiting the stars in the Milky Way of which one in every four G-type stars have habitable planets. A bit of math tells us that the volume of the Milky Way is about 17 trillion cubic light years. If you scatter 10 billion habitable exoplanets throughout this volume, you get 17 trillion cubic light years/10 billion exos = 1,700 cubic light years/exoplanet. That means the average distance between them is about 12 light years, which is very promissing!

Within 100 light years of the Sun there are 512 of these sun-like stars so there could be as many as 128 habitable Earth-like exoplanets yet to be discovered! These would be close enough to Earth to consider sending fast, unmanned spacecraft to visit them and check for lifesigns first-hand.

Welcome to the 22nd Century!

(Excerpt from my upcoming ebook ‘The Next Billion Years’)

A not unlikely interplanetary spacecraft design using known technology. Image Credit.

Thinking ahead to the 22nd seems no more of a challenge than what we had in the 1960s when we considered the mythical 21st century. But one thing is for certain, we had no idea that the socially transformative impacts of computers, smartphones and the internet would be on the horizon. We also had no idea that Stanly Kubrick’s 2001: A Space Odyssey would be way too imaginative even after Neil Armstrong walked on the moon. In the 1950s, we thought we would be driving atomic-powered cars by the 1960s. And of course, we had no idea that global warming was going to be such a problem only 40 years after the first Earth Day. One thing we do know for sure is that on April 27, 2109 Rutgers University will be opening a Time Capsule

This essay covers some ideas in space exploration and travel. A future essay will cover climate change and other issues.

Space Travel

Historically before 2025 CE, NASA’s budget was locked at about 0.5% of the federal discretionary budget and human spaceflight was allotted from this $10 billion (0.17% of federal budget). At this sustained pace,  there should be an accumulated minimum of $770 billion invested in manned activities in space by 2100 CE – the lions share going to lunar and Martian bases.  You can buy a lot of infrastructure for that amount of money even with expensive billion-dollar launch vehicles!

A stable population of over 50  researchers and engineers would be a conservative estimate. This requires only an annual off-world population growth rate of 2% by 2100 CE. They would be operating inside habitats protected from radiation exposure, have sophisticated medical and surgical facilities, and the low gravity of the moon (0.2 g’s), would not be an issue impacting astronaut (Lunites?) health. The location of this base would be near the shadowed craters in the South Pole where water ice would be mined for fuel and atmosphere. The buildings would be robotically built using 3D printing techniques developed in the 2020s. They would also be covered by radiation-proof lunar regolith. Better yet, find a lava tube and seal off its ends, then erect a pair of pressurized bulkheads and build ordinary habitats at low cost. Using 3D printing, this process can be automated.

By the start of the 22nd century, if the first human expedition to Mars occurred in 2050 CE, then 50 years have now elapsed. While a lunar base at this time may have 50-100 people, the level of difficulty in transporting material and people to Mars may not allow a Martian base with more than a dozen ‘Martians’ on a  2-year rotation back to Earth. The Planetary Society thinks there could be over 1,000 people living in a sustained way on Mars by 2070, but the devil is in the details as they say. At an off-world sustained growth rate of 2% per year, we only get to about 200 people by then including the lunar base. Of course, the  rapid commercialization of space may well create its own demand for people to visit the moon and Mars, and so extra capacity will have to be built by private companies.

Aside from billionaires, it is not known how much a trip will cost and if ordinary people being chased by climate change issues, will have the spare cash. The truth of the matter is that on Mars, there is simply nothing for a non-scientist to do to occupy their time. You will always live inside a cramped ‘dome’ and only venture outside in a spacesuit. You could hike or drive to a new destination, but you would always see essentially the same rust-red landscape unless you visited the ice-covered poles, which would be hazardous.  Psychologists say that we have limited coping skills to deal with this kind of monotony,

However, if any traces of life are discovered either as fossils or as living systems, this will entirely change the game. It is not unlikely that with indigenous Martian life, Mars will be under extreme quarantine to prevent humans from contaminating the Martian biosphere with terrestrial DNA, or coming into contact with potentially lethal viruses. 

As for the rest of the solar system, we have had tremendous success deploying robotic explorers to the moon and Mars. This technology will continue to be used with even more advanced systems that have sophisticated artificial intelligence and can operate autonomously for long periods. By the end of the 22nd century, these systems will have been placed on the surfaces of Mercury, Venus, the large moons of Jupiter and Saturn, and even a few of the distant moons of Uranus, Neptune and some asteroids too. The Curiosity rover cost $2.5 billion and has lasted over 10 years, so this technology is extremely cost-effective for the science returned. Making them fully autonomous using AI will eliminate the need for long time delays to Earth to operate them telerobotically. These systems will return to Earth high-def video that will be immediately incorporated into fully immersive Virtual Reality experiences for the general public not just a few lucky scientists.

 Astronomy

Meanwhile, astronomers will continue to have no problems forecasting eclipses and unusual planetary alignments with enormous accuracy to the day, hour and minute across the centuries.  We are still going to have two or three solar eclipses every year, but the one on June 25, 2150 will be the longest one since 1973 at 7 minutes and 14 seconds. It will be followed on July 16, 2186 by the longest total solar eclipse in 10,000 years at 7 minutes and 29 seconds. Most eclipses last only 2-5 minutes so these will be truly exceptional. 

The first transit of Venus across the face of the sun since 2012 will occur on December 11, 2117. The previous one was a major media event observed by billons of people.  Its companion event will occur 8 years later on December 8, 2125. 

Then on September 14, 2123 from Earth, Venus transits across the disk of Jupiter. The last time this happened was on November 22, 2065 and it will no doubt still be a public spectacle of some interest. 

Venus transit of Jupiter

Mars gets into the act three years later as it ducks behind the planet Mercury on July 29, 2126. Then on November 15, 2163 Mars colonists will see Earth pass across the face of the sun. This Earth transit will be repeated on May 10, 2189. Some lucky ‘Martians’ may actually get to see both events.

From Neptune, there will also be a transit of Jupiter across the sun on August 8, 2188, so if you were clever you could see the Jupiter transit first and then travel to Mars to see the Earth transit a few years later.

And among the other astronomical events, the nerds among us will wait patiently for the astronomical ‘Julian Day’ calendar to roll over to 2500000 on August 18, 2132. We also get to  celebrate the return of Halley’s Comet on March 27, 2134. Forty years later in 2178, Pluto returns to the same place in its orbit where it was discovered in 1930. But one astronomical activity will continue its essential work. 

Killer Asteroids

Earth orbits the sun in a veritable shooting gallery of asteroids that share nearly the same orbit, and comets that arrive unexpectedly from the far reaches of the solar system. 

Chelyabinsk Meteor….20-meters….1,000 people injured. Image credit.

By 2023 CE, the orbits of 20,000 ‘Near Earth Objects’ had been calculated. Hundreds of these  NEOs have been placed on a Potentially Hazardous Object watch list  because they are larger than 100 meters and could be ‘City Killers’ or worse if they impacted a populated area. The highest risk of impact for a known asteroid is a 1 in 714 chance by an asteroid designated 2009 FD in 2185, meaning that the possibility that it could impact then is less than 0.2 percent. The Sentry Risk Table only lists 2017WT28,  about 8 meters in diameter, as an impact risk for the year 2104. Its odds are about one-in-100. A 2021 survey estimates that there are over 4 million NEOs larger than 10 meters yet to be found.  However, current surveys are estimated to be more than 95% complete for objects bigger than 200 meters. This means that there are no Dinosaur Killer events of the 6km-class anytime soon.

The DART spacecraft impact with the 5-million-ton asteroid Dimorphos was a success and demonstrated we can alter the orbits of asteroids to avoid collision with Earth. (Image credit: NASA)

By the end of the 22nd century, we will have had at least one if not two more events like Tunguska in 2009 and Chelyabinsk in 2013. If we are unlucky, a city or town may be obliterated, but chances are we will be able to divert its orbit to avoid impacts using the DART technology from 2021.

New Physics

Among physicists and astronomers, the search for the nature of dark matter and clues on how to go beyond the so-called Standard Model will inevitably be helped by new instruments. Current designs already have 100 TeV available by the end of the 21st Century, and likely 1,000 TeV by the 22nd century. Along the way, we may even discover new approaches to achieving these high energies, perhaps by harnessing free cosmic ray protons. These are known to have energies above 300,000,000 TeV, but they are unfortunately few and far between. You get one or two of these during the lifetime of a typical physicist.

Although no ‘new physics’ has been detected by 2023 CE, it is almost certain that the Standard Model will start to show its incompleteness somewhere above 20 TeV. Hopefully, the missing ingredients we discover will explain both the nature of dark matter and the origin of dark energy, which were discovered by astronomers in the 20th century.

Dark matter (blue) in the Bullet galaxy cluster. Still a mystery after 100 years?

The really good news is that even with these mysterious ‘dark’ ingredients to the universe, there are almost no examples in history where some new scientific observation did not have a complete explanation within a century of its discovery.  

Exoplanets and the Search for Life

Astronomers will also be very busy studying exoplanets and discovering ones with signs of a biosphere, leading to a surge of innovative techniques for trying to actually image the surfaces of these worlds and detect artificial illumination on their dark hemispheres or signs of industrial pollution. Beyond the ‘baked-in’ mysteries of our dark universe, the search for extraterrestrial life will have matured in some fascinating directions by now. In our solar system, we will have explored the deep oceans of Europa, Titan, probed the crust of Mars, and settled the question of whether in our solar system any other abode than Earth ever  experienced life. 

 Beyond our solar system, our catalog of over 500,000 exoplanets by then, and a thousand nearby habitable worlds discovered, will have been followed by an equally intense period of searching for biomarkers in their atmospheres, or illumination on their nighttime hemispheres. This isn’t to say that it is a certainty we will find extraterrestrial life by the 22nd century, but we will have certainly studied all the ‘low hanging fruit’ exoplanets for signs of it. Within 500 light years of the sun, we will know what planetary systems to avoid if we chose to visit them with AI-enabled spacecraft. If we don’t find any exoplanets with biosignatures in the solar neighborhood by this time, humans may never take the next step and conduct interstellar travel, at a cost of trillions of dollars per mission. What would be the point?

Meanwhile, another search-for-life pursuit will have started to mature so that it can inform us about an even bigger picture. 

Intelligent Life in the Universe

Since the late-20th century, a small cadre of intrepid and patient astronomers have been using radio telescopes to search for signs of intelligent life. On Earth, a biosphere in existence for 3.8 billion years led to beings with radio technology only in the last 100 years. The goal of these radio searches is to detect the ‘spillover’ radiation from other civilizations across the Milky Way, far outside the 1,000 light year limits we are searching for viable biospheres. Every year that goes by, and every negative result that turns up, only reinforces the statistical assessment that intelligent life capable of, or interested in, radio technology are dismally few and far between in our Milky Way.

Science fiction author Arthur C Clarke  once remarked, “Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” I don’t find the prospects of extraterrestrial life ‘ terrifying’  and am more inclined to agree with what Ted Arroway said in the movie Contact, “I don’t know Sparks. But I guess I’d say if it was just us…seems like an awful waste of space”.

 Gravity Astronomy

The discovery of gravity waves in 2015 will lead to far more sensitive instruments by the 22nd century that will lay-bare the details of the Big Bang event itself along with actual hard data on the origin of time and space. Cosmology should largely become a closed textbook with all of the essential physical details worked out and covered by newer Big Bang theories. This, of course, depends on whether the issue of dark matter and dark energy are also resolved. Stay tuned!

 Science Fiction

Recognizing the futility of creating interesting science fiction stories that begin only a few decades out, some writers have moved their stories to 2050 and beyond. Only a few Old School stories written in the mid to late-20th century still find the first decades of the 21st century interesting, and with the right technology twists to make entertaining reading. None of them were very good at predicting what the end of the 20th century would look like, so we take any fictional prognostication with  grain (ton?) of salt. Still…

2100   The Ring of Charon. Earth accidentally destroyed by a Graduate Student(Allen)

2101   Babylon 5. First Martian base established (TV).

2115   Childhood’s End. Adult humans extinct. Killed by their own mutated children(Clark)                    

 2119   Orphans of the Sky. The first Centauri expedition (Heinlein)            

 2123   Starwings. Earth Holocaust;  Interstellar travel begins. (Proctor) 

2125   Methusela’s Children – Interstellar colonies (Heinlein)  

2125  Childhood’s End. The Earth is destroyed by its evolved children (Clark)

2130   Rama Revealed. Alien artifact found(Clark)   

2140   New York 2140. Major flooding (Robinson)  

2144   Aliens.  Movie events. Need I say more?

2149   The Seeds of Aril.  Interstellar Expeditions in 1-person pods(Robertson)

2150   Dr Who.  Earth overrun by the Daleks. (TV)

2150   The Expanse – Mars population 100 million (TV)

2156   Babylon 5 – The Centauri civilization contacts Earth.

2171   Moving Mars – Major Mars colony established (Bear)

2190   Seetee Ship – Story events (Williamson)

2195   Ender’s Game –  Interstellar war with aliens (Card)

Desciphering Webb Telescope Images

Astronomers can look at images of celestial objects like planets, nebulae and galaxies and immediately see their significance, but for the average person seeing them on the Evening News the pictures are, of course, beautiful but at the same time, generally mysterious. My recent book The Hidden Universe takes 68 images you might have encountered, shows you how they were created, and what interesting story lurks beneith their gorgeous countenences. This blog will describe one of these.

By now you have seen the spectacular images provided by the Webb Space Telescope (JWST), and boy are they breath-taking even for an astronomer! I have been waiting all my professional life for HD-quality images of objects in the mid-infrared spectrum (wavelength: 1 to 28 microns), and JWST has not dissappointed. NASA’s Spitzer Space Telescope also produced high-quality infrared images to be sure (wavelength: 3 to 160 microns), but JWST is a much-larger telescope (50-times larger than Spitzer) with decades-more-modern sensors!

For a full array of Webb’s first images and spectra, please visit: https://esawebb.org/initiatives/webbs-first-images/

Selecting Your Color Pallet

The first thing to remember when looking at JWST images at wavelengths between 0.6 and 28-microns is that they are not colorized the way your eye would see the light. Human eyes end their color sensitivity to visible light at around 0.6-microns, so the idea that something seen by JWST would ‘look green or red’ is completely incorrect. JWST, in fact many astronomical images used in research, are colorized to help the astronomer detect differences in how objects emit light at different wavelengths.

Our brain has evolved our color vision to be a sophisticated pattern-recognizer, so all you have to do is put your data into ‘RGB’ form, and BANG! you can use the image processing power of the wet-ware in your brain to quickly survey a new subject.

The particular color pallet an astronomer uses is all about their artistic sensibility and what they want to emphasize, so it is not unreasonable for a bright red color to be used to represent hot dust and bright blue colors for cooler dust, etc. Ironically, in the electromagnetic spectrum, red wavelengths are cooler objects and blue wavelengths are hotter objects, but humans feel that blue is a cooler color than red, so our interpretation of color is backwards! For astronomers, you can even colorize the speeds of gas clouds (ie Doppler shift) so that blue colors represent clouds moving towards you and red clouds are clouds moving away from you, irrespective of the wavelength being used.

Image Analysis 101.

To analyze JWST images, let’s start with an image that has become an astronomical and even world-wide ‘classic’: The Pillars of Creation.

Vital Statistics: The ‘Pillars’ are actually a small part of the Eagle Nebula, also called Messier 16. This is a beautiful star-forming region in the constellation  Serpens located 7,000 light years from Earth. With a size of about 60 light years, the region contains 8,000 stars  of which the brightest of these, HD-168076, is 80 times the mass of our sun and only a few million years old. Its intense ultraviolet light illuminates the nebular gas and causes the atoms to emit the colorful patina of light that we see in optical photographs. Here is what the entire nebula looks like with ‘true color’ RGB filters in the visible spectrum:

        This three-color composite optical image was obtained with the Wide-Field Imager camera on the MPG/ESO 2.2-meter telescope at the La Silla Observatory. At the center of the nebula you can see the Pillars silhouetted against the bright nebular gases, which makes these ‘dark nebulae’ really stand out. The cluster of bright stars to the upper right is called NGC 6611, which the Pillars are pointing at, and are the home to the massive and hot stars that illuminate the Pillars.

Ionizing Radiation: The intense ultraviolet radiation from the massive stars in the cluster at the upper-right is actively eating away at the dense interstellar cloud that gave birth to them at the lower-left. These are what astronomers classify as O and B-type stars or just ‘OB’ stars. Each is more than 5 times as massive as our sun, and with surface temperatures above 20,000o C they emit most of their light at ultraviolet wavelengths. Astronomers can detect this ionized gas at radio-wavelengths too. They are called ‘HII’ (H-two) regions because HI is the symbol for ordinary ‘neutral’ hydrogen and ‘II’ means that the neutral hydrogen atoms have lost one electron to make them ionized, hence ‘HII’. This ultraviolet radiation streaming through the hydrogen HI gas to ionize it into HII results in many unusual wind-swept shapes including what astronomers call ‘elephant trunks’ such as the Pillars. Their shapes act like ‘wind socks’ and point towards the main source of the ionizing gas flow, which is expanding outwards from the OB star cluster at speeds up to 10 km/s….. that’s about 22,000 mph. At this pace, the ionzation front can travel 4 light years in 100,000 years, which is enough to cross the space of most star-forming regions.

What you also notice is that the optical image shows the Pillars as dark and obscurring the background nebula which we call ‘dark nebulae’, while the JWST image shows the Pillars being very bright as ’emission nebulae’. The bright emission nebula produced by the stars is also missing in the JWST image, and instead you see thousands of stars in the background. The reason this happens is your first exposure to astrophysics!


Here is a side-by-side comparison of the Hubble (left) and Webb images (right).

Interstellar Dust: Interstellar gas clouds would be entirely invisible were it not for the fact that for about every trillion atoms of gas you have one dust grain. These dust grains are about 1-micron in diameter and were formed in the cool atmospheres of ancient red super giant stars like rain condensing out of a storm cloud on Earth. The dust grains do two things. First they scatter light at optical wavelengths, just like the dust in our atmosphere does, making the sky (or a nebula) appear blue. Secondly, they are very cold, but even so they emit their own ‘heat radiation’ in the infrared spectrum. If a cloud contains lots of dust grains, it will obscure the light from background stars, but at the same time emit infrared radiation making them appear bright at infrared wavelengths. This is what we see in the Pillars.

These linear Pillar clouds are about 2 to 4 light years in length and are rich in dust grains, so they block optical light in the famous Hubble images making them look dark, but emit their own radiation making them look bright at infrared wavelengths in the JWST images. For the first time, astronomers can study just how lumpy the surfaces of these interstellar clouds are by looking at the infrared light they are emitting directly. Taking a closer look at the Pillars gives even more information.

Close up of the Pillars dust cloud showing stars being born – red dots and color near center of image.

Star-forming regions: Zoom in a little more, until you see red dots springing into view. There are dozens of them. Each of those red dots covers an area larger than our solar system. The finger-like protrusions are also larger than our solar system, and are made visible by the shadows of evaporating gaseous globules (EGGs), which shield the gas behind them from intense UV flux. EGGs are themselves incubators of new stars. The stars then emerge from the EGGs, which then are evaporated.

So there you have it! One picture rendered into ‘a thousand words’. To be sure, this one image will easily form the basis for someone’s PhD thesis because it is so rich in detail missing from even the best Hubble images. When combined with spectroscopic data from JWST and data from radio astronomy, we will have a detailed understanding of just ONE star-forming region in our Milky Way. We are definitely living in exciting times for astronomical research!

If you want to see more astronomical images analyzed this way, have a look at my new book ‘The Hidden Universe’ available at Amazon.

Check back here for my next blog!

The Last Total Solar Eclipse…Ever!

Credit  Luc Viatour  https://Lucnix.be….An email to Viatour Luc would be appreciated too.

Well…The answer is 700 million years from now, but the details are interesting!

Since the dawn of recorded history, humans have had a love-hate relationship with total solar eclipses. For most of human history, these events were feared and taken as omens of the downfall of empires or the end of the world. Only in the last thousand years or so have people settled down and viewed them as the beautiful and bizarre events that they are. By the 19th Century, scientists and artists traveled the world over to capture them with sketches at the telescope eyepiece. Among the first images taken by primitive cameras were those of total solar eclipses.

Predicting total solar eclipses

Today, the physics and mathematics of these events are known with such detail that they can be predicted to within minutes from 2000 BCE to 3000 CE [1]. They can even be used to track the slowing down of earth’s rotation by comparing the predicted time and place with historical observations [2]. But total solar eclipses require a precise geometric circumstance to exist. Our moon has a diameter of 3,475 km at a perigee distance of 363,300 km, while the sun has a diameter of 1.4 million km at a distance of 150 million km. This means that, although the sun has a diameter that is 403 times the moon, it is 412 times farther away so that the apparent size of the dark lunar disk completely covers the blinding disk of the sun in the sky. Depending on the exact timing of the moon in its orbit, this ratio of 403/412 can be made to be exactly equal to 1.00 so that the disk of the moon exactly covers the sun to give the classic total solar eclipse shown in the picture above. But this precise geometric circumstance is not written in stone. In fact, to get a proper prediction far into the fiuture you need a supercomputer!

Earth orbit evolution

Currently the distance from earth to the sun has an average value of 150 million km, but because Earth’s orbit is an ellipse, it varies from 152 million km in July to 147 million km in January. This leads to the ironic circumstance that in the Northern Hemisphere, the sun is actually farthest away from the sun in the summer and closest in the winter! Only the Southern Hemisphere with its reversed seasons gets it right!

For many decades, researchers have modeled the evolution of the orbit of the Moon and Earth with supercomputers and pretty much nailed down what we can expect to happen for the next few billion years. As it turns out, this is a fiendishly difficult calculation because it depends on an exact knowledge of the interiors of the moon and earth, the location of the continents, and the influences of the other planets. The inner solar system is dynamically unstable and displays a chaotic behavior over times of 100 million years or longer. A consequence of this is that even changing the location of Mercury in its orbit by 1 meter today causes a variety of different outcomes in a billion years including its collision with Venus and ejection from the solar system. Earth, however, seems to exist in a remarkably stable gravitational balance such that its orbit changes only insignificantly from what we see today. [3] It will drift outwards from the sun by a few thousand kilometers due to the sun itself losing mass. The sun converts 4 million tons of mass into radiant energy every second and added up over millions of years, this causes the sun’s gravitational hold on Earth to weaken and its orbit to drift outwards by 1.5 cm/year [4].

The outward drift of Earth in its orbit is entirely negligable so we won’t bother including it. We will assume that the average perihelion and aphelion distances will still remain close to 147 and 152 million km. This means that from Earth the angular diameter of the sun from the surface will vary between 1,964 seconds of arc at perihelion to 1,900 seconds of arc at aphelion, where 3600 seconds of arc equals 1 angular degree.

Lunar orbit evolution.

The moon raises ocean and solid-body tides in Earth. The tidal bulge accelerates the moon in its orbit and the orbit of the moon increases over time. The tidal bulge also slows down Earth’s rotation and lengthens the length of its ‘day’.

We know from geologic data that our moon was formed some 4.4 billion years ago and orbited Earth at a distance of only about 30 Earth Radii ( 190,000 km) causing Earth to have a rotation period of about 12 hours in a ‘day’. [5]. Since its formation, it has drifted out to its present distance at a current rate of about 3.8 cm/year based on lunar laser metrology [6]. But this outward drift continues today so that in the future the moon will be even farther from Earth. This means that at some time in the future, the ratio of lunar:solar size and lunar:solar distance will fall below the magic 1.000 needed for a total solar eclipse. The moon will simply be too small in apparent size to perfectly cover the disk of the sun. We can’t predict the exact date when we will see the very, very, very last total solar eclipse from Earths surface, but we can get a pretty good idea what timescales are involved.

Simple Linear Model

Suppose we just used the current perihelion and aphelion distances and then assumed that the moon is moving away from Earth at a constant rate of 3.8 cm/year. If we calculate the angular sizes of the moon and sun from Earth we get the following figure.

Explanation: The orange line is the angular size of the sun viewed from Earth when Earth is closest to the sun (perihelion) and the yellow line is the same calculation from when Earth is farthest from the sun (aphelion). The black line is the angular diameter of the moon at its farthest distance from Earth (apogee) and the green line is for its closest distance to Earth (perigee). What you see is that the lunar curves cross the solar curves and indicate when these two diameters are equal, allowing a total solar eclipse to be viewed. So long as the solar lines are between the two lunar lines, you will have a total solar eclipse.

What this graph says is that 1044 million years ago, the sun at perihelion matched the moons size at apogee when it had the smallest angular size. After this ‘year’ the moons size at apogee was too small to cover the sun at perihelion and so total solar eclipses at lunar apogee ceased to happen when the solar disk was largest at perihelion. Notice that before 1044 million years the lunar lines were above the solar lines. This means that the disk of the moon was always much greater than the disk of the sun at any time in the lunar orbit. In fact, the lunar disk was so big that not only was the disk of the sun covered by the moon but much of the inner corona too. You would still have total solar eclipses before 1044 million years ago, but they would look dramatically different than the ones we see today.

By the time we get to 710 million years ago, the moon at apogee was also too small to cover the sun at aphelion when the solar disk is smallest. Between 1044 and 710 million years ago, the small apogee moon could still cover the sun when the sun was between aphelion and perihelion, but after 710 million years ago, there would never again be a total solar eclipse of the sun when the moon was at apogee. This was before the emergence of multi-cellular life on Earth during the Cambrian Explosion. Only annular eclipses will be viewed from then on during lunar apogee.

Now the second lunar curve in green is more interesting. It shows the angular size of the perigee moon, and it is pretty clear that today (Time-0) the size of the perigee moon is larger that the sun at both perihelion and aphelion. So we get total solar eclipses no matter if Earth is at perihelion or aphelion. However, by 280 million years from now, the moon will start to become smaller than the solar disk at perihelion and so eclipses will stop being total solar eclipses when the sun is closest to earth and the moon is also closest to earth. After 613 million years from now, you will no longer have total solar eclipses for the perigee moon and the smaller aphelion sun. After 613 million years the lunar disk will never again be big enough to completely cover the solar disk. This is the estimate you are likely to find in many popularizations of this Final Event such as a SpaceMath problem at NASA, and NASAs lunar scientst Dr. Richard von Drak.

A More Accurate Calculation.

The previous linear calculation was based on the moon maintaining its outward 3.8 cm/yr motion for the next 600 million years, but detailed supercomputer calculations of the evolution of the Earth-Moon system give a more accurate result. I used the model published in 2021 by Prof. Houraa Daher and her team at the University of Michigan [7], and specifically used their Figure 5a, which gave the past value for the lunar orbit semi-major axis. I also used the 2020 data from the published work by Dr. Bijay Sharma [8] at the National Institute of Technology in India, specifically Figure 7, which gave the recession speed (cm/yr) with lunar semi-major axis. Ideally, both of these data should be derived from the same calculations but unfortunately this was not possible to obtain at the time of this writing. However, if they are both faithful to the same underlying physics, then the results should be consistent.

The application of these detailed models to the lunar size evolution is shown in the next figure.

The straight, linear extrapolations have now been replaced by more realistic curved predctions. Here we see along the black line that at 700 million years ago, the lunar size at apogee matched the solar disk size at perihelion (1952 arc-seconds) , some 300 million years later than the linear model. By 500 million years ago the apogee lunar disk no longer covered the disk of the sun at aphelion, so from this time forward there were no longer any total solar eclipses when the moon was at its farthest apogee distance. This happened around the time of the Cambrian Explosion.

Meanwhile, the green line for the perigee moon shows that it has a disk size greater then the size of the large perihelion sun (1952 arcseconds) disk until 300 million years from today. At this time, the lunar diameter varies from 1718 arcseconds (black line) to 1952 arcseconds (green line) so we can still have total solar eclipses so long as the moon is close to its perigee when the sun passes through one of the lunar ‘nodes’ during the equinoxes. At about 700 million years from now the large perigee moon with a diameter of 1952 arcseconds covers the sun at perihelion, but after this time, its diameter continues to decrease until from this time forward all we ever see are annular eclipses. So this critical ‘date’ is about 80 million years later than the linear model.

By 700 million years from now, the moon will continue to drift away from Earth, but at a slower rate of 3.0 cm/year. Its distance from Earth will have grown from 60.2 Re (384,400 km) to 63.8 Re (407,155 km). The moon will then take 28.4 days to orbit Earth having gained about 26.4 hours since today. This means that the time between one full moon and the next will be 30.7 days instead of the current 29.5 days. Meanwhile, the Earth’s rotation has changed from its current 23h 56m to about 26h 25m as the lunar tides continue to do their work. What this means is that an Earth Year at 700 million years from today will only about 330 days long!

Will there be anyone there to care? Probably not.

Our sun continues to evolve and grow in luminosity so by then it will be about 10% more luminous than it is today.  This means the average global temperature will be 117o F and not the 57o F we enjoy today. By this time, the level of carbon dioxide will have fallen below the level needed to sustain C3 carbon fixation photosynthesis used by trees.  Some plants use the C4 carbon fixation method to persist at carbon dioxide concentrations as low as ten parts per million. However, the long-term trend is for surface plant life to die off altogether. The extinction of plants  will be the demise of almost all animal life since plants are the base of much of the animal food chain on Earth. Climate models suggest that by about this time Earth will be hot enough to cause the slow evaporation of the oceans into the atmosphere. This will be the start of what is called the “moist greenhouse” phase, resulting in a runaway evaporation of the oceans and Earth becoming Venus.  Meanwhile, the current continents will have merged and separated and merged again into yet another supercontinent with its own lethal contribution to global heating and weather [9].

So basically by about 700 million years from now, Earth will be a humid, desert world with no complex living organisms to appreciate total solar eclipses except perhaps extremophile bacteria…and cockroaches?

Have a nice day!

[1] Five Millennium Catalog of Solar eclipses https://eclipse.gsfc.nasa.gov/SEcat5/catkey.html

[2] Ancient eclipses Reveal How Earths Rotation has Changed https://www.space.com/ancient-eclipse-records-earth-rotation-history

[3] Highly Stable Evolution of Earths Future Orbit Despite Chaotic Behaavior of Solar System https://iopscience.iop.org/article/10.1088/0004-637X/811/1/9

[4] https://www.forbes.com/sites/startswithabang/2020/04/09/earth-is-spiraling-away-from-the-sun-for-now-but-will-eventually-crash-into-it/?sh=863220238580

[5] Long-Term Earth-Moon Evolution With High-Level Orbit and Ocean Tide Models https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JE006875 figure 6

[6] The moon has been drifting away from Earth for 4.5 billion years. A stunning animation shows how far it has gone. https://www.businessinsider.com/video-moon-drifts-away-earth-4-billion-years-2019-9

[7] Long‐Term Earth‐Moon Evolution With High‐Level Orbit and Ocean Tide Models, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9285098/

[8] The Past, Present and the Futuristic Earth-Moon Orbital-Global Dynamics – and its habitability – https://www.proquest.com/openview/c945a68d9b4a2354aaea7cf859b776ba/1?pq-origsite=gscholar&cbl=4882998

[9] What if You Traveled One Billion Years into the Future? https://whatifshow.com/what-if-you-traveled-one-billion-years-into-the-future/

Math Anxiety: Origins and Cures

Portrait Of Student With Head Down On Stack Of Books

Someone asks you to perform a simple arithmetic calculation, or perhaps you encounter these while doing your income tax. As a consumer you might want to compare the cost of two products with different sales prices. Or perhaps the tags give  you the same product by two different manufactures who tell you the unit cost, but the products are  in either 12-count or 18-count packages. The odds are very good that along with millions of other adults you will have some trepidation in ‘doing the math’. That’s because math anxiety (MA) is endemic not only among US adults but around the world. It crosses ethnic groups, cultures and continents. According to a recent study of MA[1] 93% of all adults in the US suffer from some level of this condition; internationally and across many cultures, this incidence can be over 40%.  It is reinforced by parents, the news media, and even by teachers using outdated pedagogy– all with devastating consequences, long-term. Like ADHD, you can find yourself somewhere on the Math Anxiety Spectrum. Your location might even change as you advance from childhood to adulthood.

Your Brain on Math

The evolution of our brains over millions of years has prepared it to do many kinds of math but often at an unconscious level. We, along with thousands of other species, have an innate ability to compare quantities and figure which is larger. Some species can even count including chimpanzees, crows, bees and frogs[2]. Our brains come hard-wired at birth to understand addition and subtraction. There are actual brain neurons in the parahippocampal cortex that are only active during addition while others are only active during subtraction[3].They also respond when the instruction is written down symbolically as a word or a symbol (five and three  or 5+3).

Credit: https://anthonybonato.com/2016/04/20/this-is-your-brain-on-mathematics/

The number of brain regions involved in mathematics performance reads like a catalog of nearly half of the cerebral cortex itself. This means that many of these math-activated regions are also used for other purposes in the brain. This is a common feature of brain architecture in that regions are recycled to form other neuronal networks depending on the task at hand.

  • Dorsolateral prefrontal cortex
  • Left inferior parietal lobe
  • Left precentral gyrus
  • Left superior parietal lobe
  • Left supramarginal gyrus
  • Left middle temporal gyrus
  • Insula
  • Middle cingulate cortex
  • Middle frontal gyrus
  • Superior temporal gyrus
  • Inferior frontal gyrus
  • Thalamus
  • Bilateral intraparietal region
  • Dorsal prefrontal region
  • Inferior temporal region

As a brain matures, these regions respond to external experiences but are always influenced by innate survival instincts provided by the limbic system composed of the thalamus and the amygdala. When no previous  negative experiences trigger a limbic response for fight-or-flight, all is well.  Even by the age of 7, children still have an enthusiastic and playful attitude towards math. This attitude unfortunately starts to wane in direct proportion to the number of negative performance tests they experience, which is why MA arises.

A common view shared by many MA students is that, unless I can do math quickly, I must not be very good at it. This is also a pervasive attitude among adults who, despite performing well in grade-school math may still not see themselves ‘good’ at math. Math skills are unlike reading skills because there has evolved over time a massive social permissiveness to being a poor math performer that simply  isn’t found in other academic topics.

Thanks to advances in brain research and mapping, we have a ring-side seat into what brain regions and neuronal circuitries are responsible, not only for handling mathematical problem-solving of increased sophistication, but how this process maps into generating anxiety. There is even a specific brain protein called MAOA that correlates with MA and can be used to spy on your emotional state as you are confronted with different problems.

Math comprehension and execution, like our language centers (Broca and Wernicke Regions) are activated primarily in two main regions: The parietal lobe is involved with calculating and processing numbers; The frontal lobe is involved in recalling numerical knowledge and working memory[3].

The sub-region called the dorsolateral prefrontal cortex is most curious because it is also activated as we regulate our emotions. For example, most children learn how to tone-down their glee at winning a game when they see their friends are mortified at  having lost. In math this region seems to be activated when the individual is keeping track of more than one concept at a time[2]. This region, which in math helps us keep relevant  problem-solving information ‘fresh’ in our working memory,  is also shared by circuits that allow us to suppress selfish behavior, foster commitment in relationships, and inferring the intentions of others, which is called a Theory of Mind. Researchers have proposed that math training not only makes us better at math, but also strengthens our ability to moderate our feelings and our social interactions because of the brains proclivity in  sharing brain regions for other purposes.


The Amygdala Hijack

Brain imaging studies[3] show that individuals with MA, not unexpectedly, activate circuits associated with negative emotional processing (amygdala, prefrontal cortex), the experience of pain (insula), but also areas involved with inhibiting irrelevant information, and conflict processing. The emotional control network is activated even before mathematical performance occurs. MA does its dirty work by literally robbing the individual of resources in its working memory so that they no longer have access to recalling how similar problems were previously solved. In fact, actual physical changes to the brains of MA students were found in the amygdala, the anterior corpus callosum, the right inferior frontal sulcus and the pericallosal sulcus. In particular the right amygdala volume is smaller and more reactive in students with MA[4]. Chronic hyperactivity of the amygdala in response to stress results in cellular atrophy and a decreased ability to regulate negative emotions. This effect continues into adulthood, so repeated negative math experiences in childhood alters the way that adults handle MA in a way that is both cumulative and apparently not easily mitigated in adulthood because it involves physical changes (atrophy) to specific brain regions.

One of the most troubling features of exercising a math skill is that the regions used are also connected via neuronal synapses to  the prefrontal cortex and to the amygdala. The PFC is a vital executive brain region used for synthesizing data symbolically, keeping information present in a ‘working memory’ and forecasting what happens next. This means that getting better at math allows your PFC to be trained to make better decisions about the future. But here is the BIG PROBLEM. The amygdala also watches over this process and stamps it with an emotional context. Under conditions were the stress hormone cortisol is elevated, the amygdala sees your current condition as a fight-or-flight situation and ‘hijacks’ your brain. [5]This immediately shuts down your PFC and flavors your conscious thinking with the survival instinct of wanting to flee the situation. Forget about logic and planning – it’s time to run! Of course this is not possible when working on a difficult math problem, plus the hijack has now robbed you of clear executive thinking, planning and working memory, which only increases the cortisol.

Defeating MA

This cycle of increasing stress can be defeated by first recognizing it is happening   (sweaty palms, rapid heartbeat), using deep slow breathing, and especially clearing your mind of intrusive thoughts. It only takes 90 seconds to defeat this progression. But sometimes, putting yourself in a state where MA cannot get a toe-hold is ‘simply’ a matter of not triggering the Amygdala Hijack in the first place. Here are some recommendations for teachers from researchers who have studied this triggering process.

  • Incorporate math into real-world concepts that students understand.
  • Focus on the fun elements of math like pattern making and a curiosity about numbers, not on rote memorization and theory.
  • Have them see how numbers and data literacy surround them in life from supermarket shopping to predicting future trends.
  • Avoid negative self-talk. Train yourself to have a positive attitude.
  • Consider math as a foreign language that takes practice.
  • Break the vicious downward cycle  of a bad test grade leading to lower self-esteem leading to another bad test grade leading to still-lower self-esteem.
  • Never scold a student for being wrong or having failed to perform a ‘simple’ math task.
  • Never tell your child ‘I was never good at math either’. This tells the child they can succeed in life without knowing math, which is demonstrably false in the 21st century.
  • Find ways to provide alternate student assessments rather than timed tests. This is a major source of stress and a key factor in MA.
  • Investigate ‘mixed-ability’ groupings to avoid placing MA student together, which only reinforces and normalizes  MA through peer-pressure.
  • Make math fun with lots of positive reinforcement. This reduces stress and heart rates and mitigates MA.
  • Have parents read math-related bedtime stories.
  • Encourage understanding not rote memorization. STEM professionals are those who think slowly, creatively and deeply..not necessarily quickly.
  • Display ‘anchor charts’ with examples of work, previous problems or formulas as visual clues to recall previous material.
  • Draw or write down facts or relevant equations before working on a math problem
  • Have students describe the problem to a partner to help articulate their thinking
  • Start the class with a ‘diffuser’ such as sharing a joke, or asking ‘who can tell me something we did in class yesterday?”
  • Focus on how a student got their answer and not on it whether it is right or wrong. If incorrect the student may realize this as they explain the process they used.
  • Allow students to post pictures or written explanations of their methods of solving a problem.
  • Pay attention to the words you use. Instead of ‘this is easy’ say ‘this is like the problem we did yesterday”.
  • Always project a positive, confident attitude to support modeling MA-free behavior and attitudes.

Genetic Predispositions

Here’s some bad news. MA might be genetically inheritable. The epigenetic genome controls how genes are expressed. It represents an additional way that traits and tendencies can be passed on. It is well known that traumas to parents can be passed to children, especially starvation and malnutrition. If the starving mother is pregnant, the epigenome she gives to her fetus can cause childhood difficulties in expressing proteins needed for proper digestion. Epigenetics also seems to explain how stress-related disorders can be inherited. According to a review article by TruDiagnostic published in 2020[6], the amount of cortisol in the brain can be regulated by the inherited epigenetic genome and predispose a child to stress-related behavior. It is not impossible that the same transfer of tendencies might happen that predispose the child to MA.  MA seems to result from an interaction of genetic vulnerability with negative experiences learning math. Only an unkind word from a teacher, parent or social group would be enough to set MA in motion, full-blown.

Researchers have also found that a molecular genetic marker called the monoamine oxidase A gene (MAOA) when not expressed at high enough levels correlates with increased MA especially in girls who are known from other studies to be especially susceptible to MA[7]. However, Zhe Wang at Ohio State finds that genetic factors may only account for about 40% of the individual differences in math performance based on a study of 216 twins “If you have these genetic risk factors for math anxiety and then you have negative experiences in math class, it may make learning that much harder.”[8]

MA causes millions of children, especially girls, to not consider STEM careers. This can relegate them to lower-paying jobs that are less quantitative in skill-set. With manual cash registers, some arithmetic acumen was always required even in low-paying sales jobs. Today, change is made with computerized terminals so low-paying jobs require virtually no math and are free of MA triggers.  However, the consequences of not continuing  math education in adolescence can be potentially disastrous not only reducing their career options but in the actual development of their brains.

A recent study of adolescents in the UK shows that a lack of math education affects adolescent brain development. In the UK, students can elect to end their math education at age 16.  The chemical called gamma-Aminobutyric acid (GABA) is present in the middle front gyrus (MFG), which is a region involved in reasoning and cognitive learning. GABA levels are a predictor of changes in mathematical reasoning as much as 19 months later.  What was found among the older adolescents was that GABA showed a marked reduction[9]. Because this chemical is also involved in brain plasticity and the ability to learn new skills and thinking, this reduction at this critical stage in brain development can have far-reaching impacts into adulthood.

Don’t worry…Be happy

But the good news is the brain is not a static thing. It is very ‘plastic’ when it comes to learning and dealing with new experiences. With patience and a more-supportive classroom environment, students can be shown how to make other associations between math and emotions, but this time ones that mitigate MA.


References

[1] Brain areas associated with numbers and math, 2018, doi.org/10.1016/j.dcn.2017.08.002 

[2] Mental math and the fine-tuning of emotions. Sandra Ackerman, 2017, Dana Foundation Blog, dana.org/article/mental-math-and-the-fine-tuning-of-emotions/

[3] Dorsolateral Prefrontal Cortex, 2013, Simmon Moss,  and Wikipedia [ref 8]

[4] Neurostructural correlate of math anxiety in the brains of children. Karin Kucian et al,   Translational Psychiatry, 2018; 8:273. Doi: 10.1038/s41398-018-0320-6. And www.ncbi.nlm.gov/pmc/articles/PMC6288142/

[5] The stress-learning connection: Manage an Amygdala Hijack in three steps. The Brain Health Magazine, 2022, thebrainhealthmagzine.com/hormones/the-stress-learning-connection-manage-an-amygdala-hijack-in-three-steps/

[6] Epigenetics and Anxiety – The relationship between genes and stress-related disorders, 2020, blog.trudiagnostic.com/epigenetics-and-anxiety/

[7] MAOA-LPR polymorphism and math anxiety: A marker of genetic susceptibility to social influences in girls, 2022, Annals of the New York Academy of Sciences 1516(1), DOI:10.1111/nyas.14814.

[8] Who’s afraid of math? Genetics plays a role but researchers say environment still key, 2014, geneticliteracyproject.org/2014/03/19/genetics-plays-a-role-in-math-anxiety/

[9] www.sciencedaily.com/releases/2021/06/210607161149.htm and DOI:10.1073/pnas.2013155118

Do Other Dimensions REALLY Exist?

Those of you who have been following physics for the last few decades have no doubt heard about string theory and how it requires that spacetime have 11-dimensions and not the four we are most familiar with (3 for space and 1 for time) . This has been a popular topic of discussion since the 1970s, and has spawned thousands of popularizations and lectures. I have actually written a few of these!

The difficulty is that we never experience even ordinary space directly, and as Einstein noted, space itself is more of a human mental construct than it is a physical feature of our world. When physicists need some additional dimensions to space to model our world, we find ourselves confused as our brains try to fabricate an inner model of what that might mean. The idea of ‘dimension’ is not what you might think. It is just another way of saying that some system you are modeling mathematically needs N numbers to define it uniquely in space and time. For example, economists work in ‘spaces’ where their models use N=4 unique numbers, so their universes are 4-dimensional too!

Space, as a physical idea is just our experience that we only need three numbers to locate a geometric point on Earth. We need its latitude, its longitude and its elevation above the surface of Earth. Two of these numbers are angles, but we can easily convert these angles into meters because the surface of Earth has a fixed radius and forms a sphere. The angles just represents the lengths of arcs on the surface.

Extending this into the solar system and beyond, we only need three numbers to define the location of a planet or a star. If we try to provide four numbers to locate any point in space, that fourth measurement can be replaced in terms of the previous three numbers. Because this minimum number is three, we say that our space is 3-dimensional. Similarly, all of Euclid’s geometry takes place on a flat surface where points are defined by two numbers, so it is a 2-dimensional surface. The figure above shows an example of ordinary 3-d space and its coordinate axis in the Cartesian ‘X, Y, Z’ system. But there are other possible coordinate systems we can use such as spherical (R, theta, phi) or cylindrical (R, theta, h), but they all define points in 3-d space by a unique three-number address. But wait…there’s more!

Three is not enough. Our physical world actually requires a time coordinate to define where objects are because, of course, all objects are in motion or are internally changing. Time is a fourth coordinate that helps us keep track of the complete history of an object as it moves through 3-d space. This path is called a worldline. This is why Einstein’s relativity refers to ‘spacetime’ as the fundamental arena in which all events take place. Spacetime is a 4-dimensional object with three coordinates expressed in terms of meters, and a time coordinate expressed in units of time such as nanoseconds, seconds, years etc. Spacetime is also called a manifold because every point in it can be uniquely defined by four numbers. There are mathematically an infinite number of these points. Because we have yet to find any evidence to the contrary, the manifold of all points in our physical universe, call it M, is just the same as the 4-d spacetime manifold proposed by Einstein’s relativity, call it M4, so in short-hand we can write a symbolic sentence: M = M4.

M4 is not big enough: What you need to keep in mind is that in our 4-dimensional world, we can obviously see that ‘space’ is very different than ‘time’. When physicists talk about our world or our universe having more than 4-dimensions, they also mean that additional coordinates are needed beyond (3-d) space and (1-d) time to keep track of the properties of matter and energy in their new theories. There is nothing about any of these additional coordinates that needs to have the same character as either space or time. All they need to be is numbers defining a 10-dimensional coordinate system. Some physicists, however, do think of these added dimensions as having some kind of space-like attributes.

Structure of extra dimensions in String theory in physics. 3D rendered illustration.

The way that these extra dimensions are added to our world to create the M of our physical universe is that they represent coordinates in a separate kind of space, call it M6, that adjoins our M4. In string theory, this M6 space is vanishingly small. You will not find traces of it in M4, so don’t worry about somehow taking a wrong turn in M4 and suddenly ending up in M6. String theory requires that M6 be a closed, finite manifold present at every point in M4. The size of each of these new dimensions is only 10-33 centimeters, which is why these M6s are called ‘compact’ manifolds. Only quantum particles and fields have access to M6, and this access causes particles to have different characteristics.

So what is M? The complete specification of our manifold can be written as M = M4 x M6. The address of each point in M is now given by, for example, the 4 coordinates (x,y,z,t) to define their location in M4, but to define the location of this point inside one of these compact M6 manifolds you need six additional numbers, which we can write as (a,b,c,d,e,f). The complete specification for points in the M manifold is then (x,y,z,t,a,b,c,d,e,f) or more neatly (x,y,z,t)(a,b,c,d,e,f) where we keep the two manifolds symbolically separate by placing parenthesis to group their respective coordinates.

So the question is, are the coordinates (a,b,c,d,e,f) dimensions of space like (x,y,z), are they more like the dimension of time in M4, or are they something else? As I said earlier, we already know that the time coordinate, t, is not at all like the other three space coordinates in M4, so there is no reason to believe that (a,b,c,d,e,f) should resemble either (x,y,z) or t. In fact, in string theory we already know something about the character of the coordinates in M6.

Very small: String theory proposes that they have a size of about the Planck Length, which is 10-33 centimeters. You can’t get lost in M6 because you always wind up back at your starting point after you have walked 10-33 centimeters!

Periodic: Some or all of these extra dimensions allow for the properties of physical quantities such as fields to have some periodic feature to them. An important quantity is the spin of a particle, which can be either multiples of 1 (called bosons) or 1/2 (called fermions). All elementary particles (electrons, quarks) are fermions, and all force-carrying particles (photons, gluons) are bosons.

Provides a complex topology: The number of times a quantity ‘wraps’ around a periodic extra-dimension, the more mass it has. When M6 is defined by these coordinates, the shapes of the M6 manifolds, called their topology, can have holes in them. String theory requires that these shapes be in a class called Calabi-Yau manifolds in order that the particles and fields resemble our world.

Metric signature: In special relativity, the distance between points in 4-dimensions, dS, is defined by dS2 = dx2 + dy2 + dz2 – c2dt2 where, for instance the symbol dx is the difference in the x coordinates between two points dx = x2 – x1. Notice that the space coordinates enter with a positive sign and the sole time coordinate enters with a negative sign. Physicists write this as the metric signature (+,+,+,-). In string theory, the extra dimensions are added with positive signs to make the string theory models work correctly to get something like dS2 = dx2 + dy2 + dz2 +da2 + db2 + dc2 +dd2 + de2 +df2 – c2dt2. So, the extra dimensions are taken to be space-like even though the maximum distance along any one of these 6 dimensions is only about 10-33 centimeters!

That is the mathematics of it, but do the extra dimensions really, really, reaally exist?

The truth of the matter is that we don’t know! If string theory is found to be incorrect, then there is no obvious reason to have a M6 at all, and so we are left with the M4 universe that we know and love. We cannot investigate the universe at the Planck scale, so the only way to test this idea of extra dimensions is to find that a theory like string theory is correct and accurate. We can then say that, because experiments confirm the predictions of string theory very accurately, there must be something like these M6 manifolds with their additional dimensions beyond the four we can directly measure in M4. On the other hand, it may also be that M6 is just mental ‘scratch paper’ that humans need in order to mathematically describe the particles and fields in our M4 universe, but our universe is actually doing something else entirely!

One important prediction from string theory is that gravity is a force modeled by closed strings in this 10-dimensional manifold. It also has the ability to range far and wide across these additional dimensions while the other three forces are confined to M4. This means that any gravitational interaction takes place in the 10-d arena and we only experience the part of this gravitational field that is in our ‘small’ 4-d universe. In fact, the theory says that this is why gravity is such as weak force because we are only seeing a small part of its full 10-d effects. This allows us to test at least this prediction by string theory.

Supernova 1987A: This supernova produced a pulse of neutrinos measured back on earth through the detection of about 12 neutrinos in the Super Kamiokande Neutrino Detector. These pulses arrived within seconds of the optical burst. Neutrinos are like the Miner’s Canaries and their numbers depend very sentitively on the energy of the collapsing supernova core into a neutron star. These 12 neutrinos matched the energy calculations, but only if the core of the star achieved its temperature by gravitational collapse, and with the energy determined by the action of gravity with little or no leakage into other dimensions. The tests were only able to say that the supernova data are consistent with these extra dimensions being smaller than about 1 angstrom (10-8 cm). So this result is a bit inconclusive.

Gravity waves: In 2017, the LIGO gravity wave detector rang out with the passing gravity wave called GW170817 from the collision between two neutron stars. The added twist was that the collision was also observed by its intense optical outburst. When detailed calculations of the energy in gravity waves and visible light were performed, the energy matched the theory exactly. The theory, based on standard general relativity, does not inlude the diminution of the gravity pulse by leakage of energy outside our M4 spacetime. The conclusion was that on this basis, gravity does not act as though there are extra dimensions! In fact, the gravity wave measurements give an observational estimate for the dimensionality of M4 of D = 4.02 +/-0.07. There is not much uncertainty to hide 6 more dimensions.

So there you have it. Those extra dimensions are probably space-like but their compact character makes them very different than either the huge space-like character of our familiar 3-dimensions to space.

Stay tuned for my next Blog in two weeks where I will be discussing the laatest Webb Space Telescope data!!!

An Old Era Ends-A New One is Born

As the international rush to get to the moon ramps up in the next few years, it is worth noting that, just as we are losing the World War II generation, we are also losing NASA’s early astronaut corps who made the 1960s and 1970’s space exploration possible.

Often called the most significant photo from space in human history, the famous “Earthrise” photo taken by Apollo 8 astronauts on Dec. 24, 1968 never fails to cause an emotional response. 

The Mercury, Gemini and Apollo astronauts are legends who made our current travel to the moon far less of a challenge 50 years later than it would otherwise have been. Since these missions completed their historic work, we have been able to mull over many scenarios for how to do it ‘right’ the next time, and so here we are. We have learned from our successes in science and engineering, but we have also learned from our failure of political nerve to go beyond the gauntlet thrown down by Apollo 17. Now we are in the midst of what appears to be a new Space Race, this time between the open societies of the ‘west’ and the closed and secretive society of China. Meanwhile, amidst this political hubris, the ranks of the Old Guard astronauts continue to thin out each year.

Project Mercury

The first group of astronauts to pass, were the original Project Mercury astronauts at the pionering, and very risky, dawn of NASA (1958-1963): Scott Carpenter, Gordon Cooper, John Glenn, Virgil Grisson, Walter Schirra, Alan Shepard and Donald Slayton. With the passing of John Glen in 2016 at the age of 95, we lost irretrivably our connection to the trials and tribulations of sitting in a ‘tin can’ as big as a telephone booth and eating food out of toothpaste tubes. These were the incredably brave men who sat on top of rockets that had only been tested a handful of times without blowing up!

John Glenn entering the Friendship 7 Mercury capsule on top of the Redstone rocket,

But more than that, these were the faces of NASA that we saw in the news media who made space travel a household word in the early-1960s. This was a HUGE transition in social consciousness because prior to Project Mercury, space travel was pure science fiction. We were a Nation obsessed by the prospects of nuclear war and Soviet spies lurking around every street corner. The adventures of the Mercury astronauts let hundreds of millions of people take a mental vacation and think about more hopeful ties to come. That plus the advent of the Jetsons TV series!

The 14 ‘Group 3’ astronauts selected in 1963 for the Gemini and Apollo manned programs

The second cohort of astronauts were those that flew with Project Gemini between 1963 and 1966. There were ten crewed missions and 16 astronauts, who conducted space walks, dockings and tested out technology and protocols for the Apollo program. Many of them went on to fly in Project Apollo having earned their ‘creds’ with Gemini.

The photo above shows, seated left to right, Edwin Aldrin (33), William Anders (30), Charles Bassett (32), Alan Bean (31), Eugene Cernan (29), and Roger Chaffee (28). Standing left to right are Michael Collins (33), Walter Cunningham (31), Donn Eisele (33), Theodore Freeman (33), Richard Gordon (34), Russell Schweickart (28), David Scott (31) and Clifton Williams (31). Additional astronauts were selected for Gemini: Frank Borman (35), Jim Lovell (35), Thomas Stafford (33), John Young (34), Neil Armstrong (33), and Pete Conrad (33). The ages of this group in 1963 spanned 29 to 35.

Whenever I look at this photo, I see these astronauts as being 10 years older than their actual age. I was a teenager during this time and anyone older than 25 or 30 looked pretty old to me. I guess for these astronauts, a military life, and the dress styles of the narrow-tie, conservative, early-60s does that to you.

NASA Astronaut Edward White floats in zero gravity of space northeast of Hawaii, on June 3, 1965, during the flight of Gemini IV.

At the present time, January 2023, the only survivors of the Mercury and Gemini groups are Edwin Aldrin (92), William Anders (89), Russell Schweickart (88) and David Scott (91). We just lost Walter Cunningham (90).

Finally, we have the Program Apollo astronauts. They were actually drawn from the Project Gemini group, but because of the premature deaths of Roger Chaffee, Ed White, Charles Bassett, and Theodore Freeman, additional astronauts were added to this project: Charles Duke, Harrison Schmitt, Ken Mattingly, Fred Haise, Wally Schirra, Edgar Mitchell, Jack Swigert, James Irwin, Alfred Wordon, James McDivitt, Ronald Evans, and Stuart Roosa.

50th Anniversary, 2019: From left to right: Charlie Duke (Apollo 16), Buzz Aldrin (Apollo 11), Walter Cunningham (Apollo 7), Al Worden (Apollo 15), Rusty Schweickart (Apollo 9), Harrison Schmitt (Apollo 17), Michael Collins (Apollo 11) and Fred Haise (Apollo 13). 
Felix Kunze/The Explorers Club

Each Apollo mission had three astronauts. Two would take the LEM to the surface for a walk-about, while the third astronaut remained behind in the Command Module. A total of 12 Apollo astronauts actually walked on the moon between Apollo 11 and 17: Neil Armstrong, Buzz Aldrin, Pete Conrad, Alan Bean, Alan Shepard, Edgar Mitchell, David Scott, James Irwin, John Young, Charles Duke, Eugene Cernan and Harrison Schmitt. Of these, the survivors by January, 2023 are Buzz Aldrin (92), David Scott (90), Charles Duke (87) and Harrison Schmitt (87).

An excellent view of the Lunar Excursion Module (LEM) “Orion” and Lunar Roving Vehicle (LRV), as photographed by astronaut Charles M. Duke Jr., lunar module pilot, during the first Apollo 16 extravehicular activity (EVA) at the Descartes landing site.

So, the surveying astronauts in January 2023 from the Mercury, Gemini and Apollo programs are, in order of age:

Buzz Aldrin (92: Gemini 12, Apollo 11),

David Scott (90: Gemini 8, Apollo 9, Apollo 15),

William Anders (89: Apollo 8),

Fred Haise (89: Apollo 13),

Russell Schweickart (88: Apollo 9),

Charles Duke (87: Apollo 16)

Harrison Schmitt (87: Apollo 17).

Ken Mattingly (86: Apollo 16, STS-4, STS-51C),

Apollo 17 astronaut Harrison Schmitt on the moon.

We are entering something of a race against time for these survivors to be present for the launch of Artemus III. Artemis III is planned as the first crewed Moon landing mission of the Artemis program. Scheduled for launch in 2025, Artemis III is planned to be the second crewed Artemis mission and the first crewed lunar landing since Apollo 17 in 1972. Buzz Aldrin (92: Gemini 12, Apollo 11) was one of the first astronauts to set foot on the lunar surface, while Harrison Schmitt of Apollo 17 was one of the last. With Buzz Aldrin and David Scott, we even have survivors from the Gemini Program who laid the groundwork for EVAs (Gemini 12) and docking maneuvers (Gemini 8).

The odds are pretty good that many of these Old Guard astronauts will still be with us to see the Artimus III lunar lander called Starship HLS reach the lunar surface, and oh what a celebration it will be at NASA!

This is Not Your Father’s Universe!

When I was learning astronomy in the 60s and 70s, we were still debating whether Big Bang or Stady State were the most accurate models for our universe. We also wondered about how galaxies like our Milky Way formed, and whether black holes existed. The idea that planets beyond our solar system existed was pure science fiction and no astronomers spent any time trying to predict what they might look like. As someone who has reached the ripe old age of 70, I am amazed how much progress we have made, from the discovery of supermassive black holes and exoplanets, to dark matter and gravitational radiation. The pace of discovery continues to increase, and our theoretical ideas are now getting confirmed or thrown out at record pace. There are still some issues that remain deliciously mysterious. Here are my favorite Seven Mysteries of the Universe!

1-How to Build a Galaxy: In astronomy, we used to think that it would take the universe a long time to build galaxies like our Milky Way, Thanks to the new discoveries by the Webb Space Telescope, we now have a ring-side seat to how this happens, and boy is it a fast process!

The oldest galaxies discovered with the Hubble Space Telescope date back to between 400 and 500 million years after the Big Bang. A few weeks ago, Webb spotted a galaxy that seems to have formed only 300 million years after the Big Bang. Rather than the massive galaxies like the Milky Way, these young galaxies resemble the dwarf galaxies like the Large Magellanic Cloud, perhaps only 1/10 the mass of our galaxy and filled with enormus numbers of massive, luminous stars. The above image from Hubble is a nearby galaxy called M-33 that has a mass of about 50 billion suns. There were lots of these smaller galaxies being formed during the first 300 million years after the Big Bang.

It looks like the universe emerged from the Dark Ages and immediately started building galaxies. In time, these fragments collided and merged to become the more massive galaxies we see around us, so we are only just starting to see how galaxy-building happens. Our Milky Way was formed some 1 billion years after the Big Bang, so the galaxy fragments being spotted by Webb have another 700 million years to go to make bigger things. Back in 2012, Hubble had already discovered the earliest spiral galaxy seen by then; a galaxy called Q2343-BX442, camping out at 3 billion years after the Big Bang. In 2021, an even younger spiral galaxy was spotted, called BRI 1335-0417, seen as it was about 1.4 billon years after the Big Bang.

So we are now watching how galaxies are being formed almost right before our eyes! Previous ideas that I learned about as an undergraduate, in which galaxies are formed ‘top-down’ from large collections of matter that fragment into stars, now seem wrong or incomplete. The better idea is that smaller collections of matter form stars and then merge together to build larger systems – called the ‘bottom-up’ model. This process is very, very fast! Among the smallest of these ‘galaxies’ are things destined to become the globular clusters we see today.

2-Supermassive Black Holes: The most distant and youngest supermassive black hole was discovered in 2021. Called J0313-1806, its light left it to reach us when the universe was only 670 million years old. Its mass, however, is a gargantuan 1.6 BILLION times the mass of our sun. Even if the formation of this black hole started at the end of the Dark Ages ca 100 million years after the Big Bang, it would have to absorb matter at the rate of three suns every year on average. That explains its quasar energy, but still…it is unimaginable how these things can grow so fast! The only working idea is that they started from seed masses about 10,000 the mass of our sun and grew from there. But how were the seed masses formed? This remains a mystery today.

3-The Theory of everything: The next Big Thing that I have been following since the 1960s is the search for what some call the Theory of Everything. Exciting theoretical advancements were made in the 1940s and 1960s to create accurate mathematical models for the three nongravity forces, called the electromagnetic, weak and strong forces. Physicists call this the Standard Model, and every physicist learns its details as students in graduate school. By the early 1980s, string theory was able to add gravity to the mix and go beyond the Standard Model. It appeared that the pursuit of a unified theory had reached its apex. Fifty years later, this expectation has all but collapsed.

Experiments at the Large Hadron Collider continue to show how the universe does not like something called supersymmetry in our low-energy universe. Supersymmetry is a key ingredient to string theory because it lets you change one kind of particle (field) into another, which is a key ingredient to any unified theory. So the simplest versions of string theory rise or fall based on whether supersymmetry exists or not. For over a decade, physicists have tried to find places in the so-called Standard Model where supersymmetry should make its appearance, but it has been a complete no-show. Its not just that this failure is a problem for creating a more elegant theory of how forces works, but it also affects astronomy as well.

https://penntoday.upenn.edu/news/making-sense-string-theory

Personally, when string theory hit the stage in the 1980’s I, like many other astronomers and physicists, thought that we were on the verge of solving this challenge of unifying gravity with the other forces, but this has not been the reality. Even today, I see no promissing solutions to this vexing problem since apparently the data shows that simple string theory is apparently on a wrong theoretical track.

One cheerful note: For neutrinos, the path from theoretical prediction to experimental observation took 25 years. For the Higgs boson, it took 50 years. And for gravitational waves, it took a full 100 years. We may just have to be patient…for another 100 years!

4-Dark Matter: The biggest missing ingredient to the cosmos today is called dark matter. When astronomers ‘weigh’ the universe, they discover that 4.6% of its gravitating ‘stuff’ is in ordinary matter (atoms,. stars, gas, neutron stars etc), but a whopping 24% is in some other ‘stuff’ that only appears by its gravity. It is otherwise completely invisible. Putting this another way, it’s as though four out of every five stars that make up our Milky Way were completely invisible.

Dark matter in Abell 1679.

Because we deeply believe that dark matter must be tracable to a new kind of particle, and because the Standard Model gives us an accounting of all the kinds of elementary particles from which our universe is built, the dark matter particle has to be a part of the Standard Model…but it isn’t!!!! Only by extending the Standard Model to a bigger theory (like string theory) can we logically and mathematically add new kinds of particles to a New Standard Model- one of which would be the dark matter particle. String theory even gives us a perfect candidate called the neutralino! But the LHC experiments have told us for over a decade that there is nothing wrong with the Standard Model and no missing particles. Astronomers say that dark matter is real, but physicists can’t find it….anywhere. Well…maybe not ALL astronomers think it’s real. So the debate continues.

Personally, I had heard about ‘missing mass’ in the 1960s but we were all convinced we would find it in hot gas, dim red dwarf stars or even black holes. I NEVER thought that it would turn out to be something other than ordinary matter in an unusual form. Dark matter is so deeply confounding to me that I worry we will not discover its nature before I, myself, leave this world! Then again, there isnt a single generation of scientists that has had all its known puzzles neatly solved ‘just in time’. I’m just greedy!!!

5- Matter and Antimatter: During the Big Bang, there were equal amounts of matter and anti matter, but then for some reason all the antimatter dissappeared leaving us with only matter to form atoms, stars and galaxies. We don’t know why this happened, and the Standard Model is completely unhelpful in giving us any clues to explain this. But next to dark matter, this is one of the most outstanding mysteries of modern, 21st century cosmology. We have no clue how to account for this fact within the Standard Model, so again like Dark Matter, we see that at cosmological scales, the Standard Model is incomplete.

6- Origin of Time and Space: Understanding the nature of time and space, and trying to make peace with why they exist at all, is the bane of any physicists existence. I have written many blogs on this subject, and have tried to tackle it from many different angles, but in the end they are like jigsaw puzzels with too many missing pieces. Still, it is very exciting to explore where modern physics has taken us, and the many questions such thinking has opened up in surprising corners. My previous blog about ‘What is ‘Now’ is one such line of thinking. Many of the new ideas were not even imagined as little as 30 years ago, so that is a positive thing. We are still learning more about these two subjects and getting better at asking the right questions!

https://iopscience.iop.org/journal/0264-9381/page/Focus-issue-loop-quantum-gravity

7-Consciousness: OK…You know I would get to this eventually, and here it is! Neuroscientists know of lots of medical conditions that can rob us of consciousness including medical anesthesia, but why we have this sense about ourselves that we are a ‘person’ and have volition is a massively hard problem. In fact, consciousness is called the ‘Hard Problem’ in neuroscience..heck…in any science!

https://www.technologynetworks.com/neuroscience/articles/what-if-consciousness-is-not-what-drives-the-human-mind-307159

The ‘Soft Problem’ is how our senses give us a coherant internal model of the world that we can use to navigate the outside world. We know how to solve the Soft Problem, just follow the neurons. We are well on our way to understanding it thanks to high-tech brain imaging scanners and cleverly-designed experiments. The Hard Problem is ‘hard’ because our point-of-view is within the thing we are trying to undertand. Some think that our own ‘wet ware’ is not up to the task of even giving us the intelligence to answer this qustion. It will not be the first time someone has told us about limitations, but usually these are technological ones, and not ones related to limits to what our own brains can provide as a tool.

So there you have it.

My impression is that only Mysteries #1 and #2 will make huge progress. The Theory of Everything is in experimental disarray. For antimatter, there has been no progress, but many ideas. They all involve going outside the Standard Model. Dark matter might be replaced by a modification of gravity at galactic and cosmological scales.

Beyond these ‘superficial’ mysteries, we are left with three deep mysteries. The origin of space, time and consciousness remain our 21st century gift to children of the 22nd century!

Check back here in a few weeks for the next blog!

Silent Earth

Noise pollution is a serious matter that can affect not only how well you sleep at night, but also your health and even psychological state. None of this should surprise you, but as our planet becomes more urbanized, the expanding cloud of man-made noise from jets, traffic and even leaf-blowers can penetrate even remote forests and habitats.

Just out of curiosity, I have created a citizen science project that you can download to your phone from your app store and help me map, not the noisiest places on this planet, but the quietest places. The project can be found by downloading from your store the app called ‘Anecdata’. It will ask you to register by entering an email address, a username and your own private password. Once registered, scroll down the project page and join the one called ‘Silent Earth’. You should also join the Facebook group called ‘The Silent Earth Project’ because I post updates there and tips for taking data, as well as interesting results along the way. https://www.facebook.com/SilentEarthProject

This is what the project banner looks like on your phone

In time, I will be using this blog space to include article of interest on noise pollution and some of our results as we get more areas covered. Here is what you need to do to get going.

Check out the national map by the National Park Service to see how your area ranks https://earthsky.org/earth/map-shows-loudest-quietest-places-in-u-s

Step 1: Tap the bar that says ‘+Observe’ on the project window

Step 2: Tap the bar that says ‘Measure’ and click ‘OK’. Remain quiet for a few seconds.

Step 3: Tap the check boxes that apply to you and your location

Step 4: Tap the ‘save’ tab at the upper right of the screen to record your data.

Don’t be shy!! Make as many measurements as you like but certainly more than one!!! Also, if it seems noisy where you are, say above 50 decibels (dB) walk around your neighborhood or town (or use a bike or car) to find a place that is quieter than what you just measured. Numbers in the 40s are very typical of suburban locations but numbers in the 30s are exceptionally quiet and what you would find in rural locations where there is little traffic, jet, plane or other man-made noises. One of the quietest places I have encountered is deep inside Skyline Caverns in Virginia where readings in the high-20s were encountered!

What is ‘Now’?

What is the duration of the present moment? How is it that this present moment is replaced by ‘the next moment’?

Within every organism, sentient or not, there are thousands of chemical processes that occur with their own characteristic time periods, but these time periods start and stop at different times so that there is no synchronized ‘moment’. Elementary atomic collisions that build up molecules take nanoseconds while cell division takes minutes to hours, and tissue cell lifespans vary from 2 days in the stomach lining to 8 years for fat cells (see Cell Biology). None of these jangled timescales collectively or in isolation create the uniform experience we have of now and its future moments. To find the timescale that corresponds to the Now experience we have to look elsewhere.

It’s all in the mind!

A variety of articles over the  years have identified 2 to 3 seconds as the maximum duration of what most people experience as ‘now’, and what researchers call the ‘specious present’. This is the time required by our brain’s neurological mechanisms to combine the information arriving at our senses with our internal, current model of the ‘outside world’. During this time an enormous amount of neural activity has to happen. Not only does the sensory information have to be integrated together for every object in your visual field and cross connected to the other senses, but dozens of specialized brain regions have to be activated or de-activated to update your world model in a consistent way.

In a previous blog I discussed how important this world model is in creating within you a sense of living in a consistent world with a coherent story. But this process is not fixed in stone. Recent studies by Sebastian Sauer and his colleagues at the Ludwig-Maximilians-Universität in Munich show that mindfulness meditators can significantly increase their sense of ‘now’ so that it is prolonged for up to 20 seconds.

In detail, a neuron discharge lasts about 1 millisecond, but it has to be separated from the next one by about 30 milliseconds before a sequence is perceived, and this seems to be true for all senses. When you see a ‘movie’ it is a succession of still images flashed into your visual cortex at intervals less than 30 milliseconds, giving the illusion of a continuous unbroken scene.  (Dainton: Stanford Encyclopedia of Philosophy, 2017).

The knitting together of these ‘nows’ into a smooth flow-of-time is done by our internal model-building system. It works lightning-fast to connect one static collection of sensory inputs to another set and hold these both in our conscious ‘view’ of the world. This gives us a feeling of the passing of one set of conditions smoothly into another set of conditions that now make up the next ‘Now’. To get from one moment to the next, our brain can play fast-and-loose with the data and interpolate what it needs. For example, it our visual world, the fovea in our retina produces a Blind Spot but you never notice it because there are circuits that interpolate across this spot to fill-in the scenery. The same thing happens in the time dimension with the help of our internal model to make our jagged perceptions in time into a smooth movie experience.

Neurological conditions such as strokes, or psychotropic chemicals can disrupt this process and cause dramatic problems. Many schizophrenic patients stop perceiving time as a flow of  linked events.  These defects in time perception may play a part in the hallucinations and delusions experienced by schizophrenic patients according to some studies. There are other milder aberrations that can affect our sense of the flow-of-time.

Research has also suggested the feeling of awe has the ability to expand one’s perceptions of time availability. Fear also produces time-sense distortion. Time seems to slow down when a person skydives or bungee jumps, or when a person suddenly and unexpectedly senses the presence of a potential predator or mate. Research also indicates that the internal clock, used to time durations in the seconds-to-minutes range, is linked to dopamine function in the basal ganglia. Studies in which children with ADHD are given time estimation tasks shows that time passes very slowly for them.

Because the volume of data is enormous, we cannot hold many of these consecutive Now moments in our consciousness with the same clarity, and so earlier Nows either pass into short-term memory if they have been tagged with some emotional or survival attributes, or fade quickly into complete forgetfulness. You will not remember the complete sensory experience of diving into a swimming pool, but if you were pushed, or were injured, you will remember that specific sequence of moments with remarkable clarity years later!

The model-building aspect of our brain is just another tool it has that is equivalent to its pattern-recognition ability in space. It looks for patterns in time to find correlations which it then uses to build up expectations for ‘what comes next’. Amazingly, when this feature yields more certainty than the evidence of our senses, psychologists like Albert Powers at Yale University say that we experience hallucinations (Fan, 2017). In fact, 5-15% of the population experience auditory hallucinations (songs, voices, sounds) at some time in their lives when the brain literally hears a sound that is not there because it was strongly expected on the basis of other clues. One frequent example is that  people claim to hear the Northern Lights as a crackling fire or a swishing sound, because their visual system creates this expectation and the brain obliges.

This, then, presents us with the neurological experience of Now. It is between 30 milliseconds and several minutes in duration. It includes a recollection of the past which fades away for longer intervals in the past, and includes a sense of the immediate future as our model-making facility extrapolates from our immediate past and fabricates an expectation of what comes next.

Living in a perpetual Now is no fun. The famed psychologist Oliver Sacks describes  a patient, Clive Wearing, with a severe form of amnesia, who was unable to form any new memories that lasted longer than 30 seconds, and became convinced every few minutes that he was fully conscious for the first time. “In some ways, he is not anywhere at all; he has dropped out of space and time altogether. He no longer has any inner narrative; he is not leading a life in the sense that the rest of us do….It is not the remembrance of things past, the “once” that Clive yearns for, or can ever achieve. It is the claiming, the filling, of the present, the now, and this is only possible when he is totally immersed in the successive moments of an act. It is the “now” that bridges the abyss.”

Physical ‘Now’.

This monkeying around with brain states, internal model-making and sensory data creates Now as a phenomenon we experience, but the physical world outside our collective brain population does not operate through its own neural systems to create a Cosmic Now. That would only be the case if, for example, we were literally living inside The Matrix….which I believe we are not. So in terms of physics, the idea of Now does not exist. We even know from relativity that there can be no uniform and simultaneous Now spanning large portions of space or the cosmos. This is a problem that has bedeviled many people across the millennia.

Augustine (in the fourth century) wrote, “What is time? If no one asks me, I know; if I wish to explain, I do not know. … My soul yearns to know this most entangled enigma.” Even Einstein himself noted ‘…that there is something essential about the Now which is just outside the realm of science.’

Both of these statements were made before quantum theory became fully developed. Einstein developed relativity, but this was a theory in which spacetime took the place of space and time individually. If you wanted to define ‘now’ by a set of simultaneous conditions, relativity put the kibosh on that idea because due to the relative motions and accelerations of all Observers, there can be no simultaneous ‘now’ that all Observers can experience. Also, there was no ‘flow of time’ because relativity was a theory of worldlines and complete histories of particles from start to finish (called the boundary conditions of worldlines). Quantum theory, however, showed some new possibilities.

In physics, time is a variable, often represented by the letter t, that is a convenient parameter with which to describe how a system of matter and energy change. The first very puzzling feature of time as a physical variable is that all mathematical representations of physical laws or theories show that time is continuous, smooth and infinitely divisible into smaller intervals. These equations are also ‘timeless’ in that they can be written down on a piece of paper and accurately describe how a system changes from start to finish (based on boundary conditions defined at ‘t=0’) , but the equations show this process as ‘all at once’.

In fact, this perspective is so built into physics that it forms the core of Einstein’s relativity theory in the form of the 4-d spacetime ‘block’. It also appears in quantum mechanics because fundamental equations like Schroedinger’s Equation also offer a timeless view of quantum states.

In all these situations, one endearing feature of our world is actually suppressed and mathematically hidden from view, and that is precisely the feature we call ‘now’.

To describe what things look like Now, you have to dial in to the equations the number t =  t(now). How does nature do that? As discussed by physicist Lee Smolin in his book ‘Time Reborn’, this is the most fundamental experience we have about the physical world as sentient beings, yet it is not represented by any feature in the physical theories we have developed thus far. There is no theory that selects t = t(now) over all the infinite other moments in time.

Perhaps we are looking in the wrong place!

Just as we have seen that what we call ‘space’ is built up like a tapestry from a vast number of quantum events described (we hope!) by quantum gravity, time also seems to be created from a synthesis of elementary events occurring at the quantum scale.   For example, what we call temperature is the result of innumerable collisions among elementary objects such as atoms. Temperature is a measure of the average collision energy of a large collection of particles, but cannot be identified as such at the scale of individual particles. Temperature is a phenomenon that has emerged from the collective properties of thousands or trillions of individual particles.

A system can be described completely by its quantum state – which is a much easier thing to do when you have a dozen atoms than when you have trillions, but the principle is the same. This quantum state describes how the elements of the system are arrayed in 3-d space, but because of Heisenberg’s Uncertainty Principle, the location of a particle at a given speed is spread out rather than localized to a definite position.  But quantum states can also become entangled. For these systems, if you measure one of the particles and detect property P1 then the second particle must have property P2. The crazy thing is that until you measured that property in the first particle, it could have had either property P1 or P2, but after the measurement the distant particle ‘knew’ that it had to have the corresponding property even though this information had to travel faster than light to insure consistency.

An intriguing set of papers by physicist Seth Lloyd at Harvard University in 1984 showed that over time, the quantum states of the member particles become correlated and shared by the larger ensemble. This direction of increasing correlation goes only one way and establishes the ‘Arrow of Time’ on the quantum scale.

One interesting feature of this entanglement idea is that ‘a few minutes ago’, our brain’s quantum state was less correlated with its surroundings and our sensory information than at a later time. This means that the further you go into the past moments, the less correlated they are with the current moment because, for one, the sensory information has to arrive and be processed before it can change our brain’s state. Our sense of Now is the product of how past brain states are correlated with the current state. A big part of this correlating is accomplished, not by sterile quantum entanglement, but by information transmitted through our neural networks and most importantly our internal model of our world – which is a dynamic thing.

If we did not have such an internal model that correlates our sensory information and fabricates an internal story of perception, our sense of Now would be very different because so much of the business of correlating quantum information would not occur very quickly. Instead of a Now measured in seconds, our Now’s would be measured in hours, days or even lifetimes, and be a far more chaotic experience because it would lack a coherent, internal description of our experiences.

This seems to suggest that no two people live in exactly the same Now, but these separate Now experiences can become correlated together as the population of individuals interact with each other and share experiences through the process of correlation. As for the rest of the universe, it exists in an undefined Now state that varies from location to location and is controlled by the speed of light, which is the fastest mode of exchanging information.

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In my previous blogs, I briefly described how the human brain perceives and models space (Blog 14: Oops one more thing), how Einstein and other physicists dismiss space as an illusion (Blog 10: Relativity and space ), how relativity deals with the concept of space (Blog 12: So what IS space?), what a theory of quantum gravity would have to look like (Blog 13: Quantum Gravity Oh my! ), and along the way why the idea of infinity is not physically real (Blog 11: Is infinity real?) and why space is not nothing (Blog 33: Thinking about Nothing). I even discussed how it is important to ‘think visually’ when trying to model the universe such as the ‘strings’ and ‘loops’ used by physicists as an analog to space ( Blog 34: Thinking Visually)

I also summarized the nature of space in a wrap-up of why something like a quantum theory for gravity is badly needed because the current theories of quantum mechanics and general relativity are incomplete, but also point the way towards a theory that is truly background-independent and relativistic (Blog 36: Quantum Gravity-Again! ). These considerations describe the emergence of the phenomenon we call ‘space’ but also down play its importance because it is an irrelevant and misleading concept.