Category Archives: Cosmology

Astronomy, Black Hole, Cosmology, Dark Matter, NASA, Planets

Ten amazing space discoveries in 2024.

The Early Universe is Running out of Supermassive Black holes.

As the Webb Space Telescope continues to find supermassive blackholes (SMBH) in the time after the Dark Ages, there has been a significant down turn in their masses. Now the most common SMBHs earlier than one billion years ABB are about 4 million solar masses – about the same mass as Sgr A* in our Milky Way.  At 700 million years ABB, Webb found a SMBH with 40 million solar masses. GN-z11 at 420 million years ABB has an estimated mass of 2 million suns. LID-568 (See NASA artwork above) has a mass of 10 million suns at an age 1.5 billion years ABB. ZS7 consists of two merging SMBHs each with a mass of about 50 million suns at an age of about 740 million years ABB. So, Webb is now giving us a glimpse of black hole mergers and rapid growth long before we reach the billion-sun masses of todays SMBHs.

Cosmic Gravity Wave Background

Teams of scientists worldwide have reported the discovery of the “low pitch hum” of these cosmic ripples flowing through the Milky Way. The detected signal is compelling evidence and consistent with theoretical expectations of gravity wave pulses from millions of distant binary hole mergers, where these black holes are of the SMBH variety. The artwork above is provided by NASA. [UC Berkeley News]

DESI survey of 6 million galaxies validates Big Bang

Researchers used the Dark Energy Spectroscopic Instrument (DESI) to map how nearly 6 million galaxies cluster across 11 billion years of cosmic history as shown in the image above (Credit: D. Schlegel/Berkeley Lab using data from DESI). Their observations line up with what Einstein’s theory of general relativity predicts. Looking at galaxies and how they cluster across time reveals the growth of cosmic structure, which lets DESI test theories of modified gravity – an alternative explanation for our universe’s accelerating expansion. DESI researchers found that the way galaxies cluster is consistent with our standard model of gravity and the predictions from Einstein’s theory of general relativity. There is even a suggestion in the data that Dark Energy is weakening as the universe ages over the last 11 billion years. This has huge implications for modeling the future of the universe. [News from Berkeley Lab]

Supersymmetry searches still come up empty-handed

Before the beginning of the Large Hadron Collider data taking, supersymmetry (SUSY)  was seen as a single answer to many unresolved open questions of the Standard Model. The LHC ATLAS research program has first quickly excluded most of the simplest SUSY configurations, then moved to a detailed work targeting many signatures, not necessarily favored by a theoretical prejudice. The lack of an identified SUSY signal so far at the massive ATLAS detector shown above (Credit: ATLAS Experiment © 2022 CERN) is certainly a disappointing and possibly somewhat surprising outcome to many scientists. A lot of theoretical effort into String theory and the search for a quantum theory of gravity hinges on going beyond the so-called Standard Model, and supersymmetry is a key mathematical ingredient to many of these simpler extensions. [LHC-ATLAS Consortium]

Dark Matter searches still find no candidate particles

After 40 years of searching for dark matter candidate particles, the currently most popular assumption for the nature of DM still is that of a (new) particle, even though the jury is not entirely out on whether the present observations of DM are due to a particle (or wave-like behavior at very low masses) or due to our limited understanding of the gravitational force at large scales. The figure above shows the current list of candidate particles being considered (Credit: CERN/G. Bertone and T. M. P. Tait) Despite its success, the Standard Model of particle physics (SM) in its present form (6 quarks, 6 leptons, 1 Higgs boson, plus the 12 quanta for the three non-gravity forces) is not able to offer an explanation for dark matter. It offers no known particle that can play that role. The LHC experiments, meanwhile, have by now completed and published all their main DM search analyses for the Run-2 data taken before 2016. No evidence as yet has been found for signals of the production of dark matter or dark sector particles. Dark matter, as a particle representing some 25% of all gravitating ‘stuff’ in the universe, remains one of the biggest puzzles in physics today.

Origin of the solar wind discovered

After several decades of theoretical speculation, solar physicists are now certain that they have discovered how our sun produces the interplanetary wind of matter that streams out of its corona at speeds of over 200 km/s. In 2024, the ESA-led Solar Orbiter spacecraft made the first ever connection between measurements of the solar wind around a spacecraft to high-resolution images of the Sun’s surface at a close distance. The spacecraft passed through the magnetic field connected to the edge of a coronal hole complex. This let the team watch the way the solar wind changed its speed – from fast to slow or vice versa – and other properties, confirming that they were looking at the correct region. In the end, they got a perfect combination of both types of features together. The image above (Credit:ESA & NASA/Solar Orbiter/EUI Team; acknowledgement: Lakshmi Pradeep Chitta, Max Planck Institute for Solar System Research) taken by the ESA/NASA Solar Orbiter spacecraft shows a ‘coronal hole’ near the Sun’s south pole. Subsequent analysis revealed many tiny jets of plasma being released into the corona and solar wind during the observation. 

The origin of the springtime, dinosaur-killer asteroid

According to a recent article published in Nature magazine, the object that smashed into Earth and kick-started the extinction that wiped out almost all dinosaurs 66 million years ago was an asteroid that originally formed beyond the orbit of Jupiter, according to geochemical evidence from the impact site in Chicxulub, Mexico. Comparisons between the chemical record left behind by the strike 66 million years ago and known meteorite samples suggest that the Cretaceous asteroid was a carbonaceous chondrite. This type of asteroid is one of the oldest known, having formed billions of years ago in the early solar system. As these chondrites can only come from asteroids found beyond Jupiter, it suggests that the asteroid must have had its origins there too. Some of the chondritic spherules got into the gills of dying fish, fossils of which have been used to reveal that  the asteroid impacted during the springtime in the northern hemisphere. This is possible to know based on where the lines of growth in the fish’s bones stop, which can be read somewhat like rings in a tree trunk.

Current round-up of fireball detections worldwide

The most recent world map of detected fireballs from 1988 to 2024 detected with a variety of sensors (optical, infrasound, etc) reveals that fireballs delivering less than 30 kilotons-equivalent TNT upon atmospheric detonation are uniformly spread around Earth’s surface. In 2019 it was determined that the Geostationary Lightning Mapper (GLM) instruments on GOES weather satellites can detect fireballs and bolides. This largely removes much of the observer-bias from the detections irrespective of geographic latitude. The bright red dot is the 2013 Chelyabinsk Meteor fireball and impact. (Credit: NASA/CNEOS/JPL)

NASA spacecraft detects subterranean Martian water

Using seismic activity to probe the interior of Mars, geophysicists have found evidence for a large underground reservoir of liquid water — enough to fill oceans on the planet’s surface. The data from NASA’s Insight lander (2018-2022) allowed the scientists to estimate that the amount of groundwater could cover the entire planet to a depth of between 1 and 2 kilometers, or about a mile. While that’s good news for those tracking the fate of water on the planet after its oceans disappeared more than 3 billion years ago, the reservoir won’t be of much use to anyone trying to tap into it to supply a future Mars colony. It’s located in tiny cracks and pores in rock in the middle of the Martian crust, between 11.5 and 20 kilometers (7 to 13 miles) below the surface. Even on Earth, drilling that deep would be a challenge. [UC Berkeley News].

Organized magnetic fields in Sgr A* black hole accretion disk

A new image from the Event Horizon Telescope (EHT) collaboration has uncovered strong and organized magnetic fields spiraling from the edge of the supermassive black hole Sagittarius A* (Sgr A*). Seen in polarized light for the first time, this new view of the monster lurking at the heart of the Milky Way Galaxy has revealed a magnetic field structure strikingly similar to that of the black hole at the center of the M87 galaxy, suggesting that strong magnetic fields may be common to all black holes. This similarity also hints toward a hidden jet in Sgr A*.Scientists unveiled the first image of Sgr A*— which is approximately 27,000 light-years away from Earth— in 2022, revealing that while the Milky Way’s supermassive black hole is more than a thousand times smaller and less massive than M87’s, it looks remarkably similar. This made scientists wonder whether the two shared common traits outside of their looks. To find out, the team decided to study Sgr A* in polarized light. Previous studies of light around M87* revealed that the magnetic fields around the black hole giant allowed it to launch powerful jets of material back into the surrounding environment. Building on this work, the new images have revealed that the same may be true for Sgr A*. [Credit EHT Collaboration]

Cosmology, Dark Matter, Gravity, Physics

Exactly how many stars are in the Milky Way ?

Based on tons of scientific data and decades of research, here is an artist’s impression of the Milky Way Galaxy, as seen from above the galactic “North pole”. (Credit: NASA. JPL-Caltech/R. Hurt (SSC/Ca)

All of the basic elements have been established including its spiral arm pattern and the shape of its central bulge of stars. To directly answer this question, however, is a difficult, if not impossible, task. The problem is that we cannot directly see every star in the Milky Way because most are located behind interstellar clouds from our vantage point in the Milky Way. The best we can do is to figure out the total mass of the Milky Way, subtract the portion that is contributed by interstellar gas and dust clouds ( about 1 – 5 percent or so), and then divide the remaining mass by the average mass of a single star.

From a number of studies, the mass of the Milky Way inside the orbit of our sun can be estimated to an accuracy of perhaps 20 percent as 140 billion times the mass of the Sun, if you use the Sun’s speed around the core of the galaxy. Radio astronomers have detected much more material outside the orbit of the Sun, so the above number is probably an underestimate by a factor of 2 to 5 times in mass alone.

Now, to find out how many stars this represents, you have to divide by the average mass of a star. If you like the sun, then use ‘one solar mass’ and you then get about 140 billion sun-like stars for what’s inside the sun’s orbit. But astronomers have known for a long time that stars like the sun in mass are not that common. Far more plentiful are stars with half the mass of the sun, and even one tenth the mass of the sun. The problem is that we don’t know exactly how much of the Milky Way is in the form of these low-mass stars. In text books, you will therefore get answers that range anywhere between a few hundred billion and as high as a trillion stars depending on what the author used as a typical mass for the most abundant type of star. This is a pretty embarrasing uncertainty, but then again, why would you need to know this number exactly?

The best estimates come from looking at the motions of nearby galaxies such as a recent study by G. R. Bell (Harvey Mudd/USNO Flagstaff), S. E. Levine (USNO Flagstaff):

Using radial velocities and the recently determined proper motions for the Magellanic Clouds and the dwarf spheroidal galaxies in Sculptor and Ursa Minor, we have modeled the satellite galaxies’ orbits around the Milky Way. Assuming the orbits of the dwarf spheroidals are bound, have apogalacticon less than 300 kpc, and are of low eccentricity, then the minimum mass of our galaxy contained within a radius of 100 kpc is 590 billion solar masses, and the most likely mass is 700 billion. These mass estimates and the orbit models were used to place limits on the possible maximum tangential velocities and proper motions of the other known dwarf spheroidal galaxies and to assess the likelihood of membership of the dwarf galaxies in various streams.

Again, you have to divide this by the average mass of a star…say 0.3 solar masses, to get an estimate for the number of stars which is well into the trillions!

Another factor that confuses the problem is that our Milky Way contains a lot of dark matter that also produces its own gravity and upsets the estimates for actual stellar masses. Our galaxy is embedded in a roughly spherical cloud of dark matter. Various theoretical calculations show that these should be very common among galaxies. Here is an example of such a model in which the luminous galaxy is embedded in a massive DM halo. (Credit:Wikipedia-Dark Matter Halo N-body simulation)

By using the motions of distant galaxies astronomers have ‘weighed’ the entire Milky Way and deduce that the dark matter halo is likely to include around 3 trillion solar masses of dark matter.

Cosmology, Gravity, Physics

Can gravity affect the speed of light?

Gravity can certainly warp and distort the ‘straight-line’ path of a light ray. This Hubble image is of the Einstein Ring LRG 3-757 in which the central massive galaxy has warped the image of a background galaxy into a ring of light. (Credit: ESA/Hubble & NASA)

The speed of light is something measured with a local apparatus in an inertial reference frame, using the same meter stick and clock. A gravitational field has zillions of such ‘locally inertial reference frames’ which are described by freely-falling observers for short intervals of time and small regions of space. In all of these tiny domains, an observer would measure the same velocity for light as guaranteed by special relativity. To ask what the speed of light is over a domain where gravitational forces make a reference frame ‘non-inertial’ and not moving at a constant speed, is an ill-defined question in special relativity. As soon as you try to measure the speed of such an impulse, you would be using a clock and a meter stick which would not be the ‘proper time and space’ intervals for the entire region where the gravitational field exists.

Gravity can affect the speed of light. If you measure the speed over a large enough region that special relativity and its requirement of a flat spacetime is not satisfied. In the presence of curved spacetime, conventional local measurement techniques do not work and so you cannot define the speed of light in exactly the same way that you do under laboratory conditions in ‘flat’ spacetime. In fact, in curved spacetime even the concept of conservation of energy is not easily defined because the curvature of space itself changes the definition. Conservation of energy only works in flat spacetime.

Cosmology, Physics

What are the ’10 dimensions’ that physicists are always talking about?

This stunning simulation of Calabi-Yau spaces at each point in 3-d space was created by  Jeff Bryant and based on concepts from A.J. Hanson, “A Construction for Computer Visualization of Certain Complex Curves,” in “Computers and Mathematics” column, ed. Keith Devlin, of Notices of the American Mathematical Society, 41, No. 9, pp. 1156–1163 (American Math. Soc., Providence, November/December, 1994). See his website for details.

We know that we need at least 4 to keep track of things: The three dimensions of space that give us freedom to move Up-Down, Left-right, and forward-backward, plus the dimension of time. These dimensions of spacetime form the yellow gridwork in the image above. At each intersections you have a new location in space and time, and mathematically there are a infinite number of these coordinate points. But the real world may be different then the mathematical ideal. There may not be an infinite number of points between 0 and 1, but only a finite number.

We know that you can sub-divide space all the way down to the quantum realm and to distances and times of 10^-20 cm and 10^-30 seconds and spacetime still looks perfectly smooth to the physics we observe there, but what if we go down even further? Since the 1940s, a simple calculation using the three fundamental constants h, c and G has turned up a smallest quantum distance of 10^-33 cm and 10^-43 seconds called the Planck Scale. In our figure above, the spacings in the yellow grid are at this scale of intervals, and that is the smallest possible separation for physical processes in space and time..it is believed.

Since the 1970s, work on the unification of forces has uncovered a number of ideas that could work, but nearly all require that we add some additional dimensions to the four we know. All of these extra dimensions are believed to appear at the Planck scale, so they are accessible to elementary particles but not to humans.In string theory, these added dimensions are rolled up into identical but complex mini-geometries like the ones shown above.

No one has the faintest idea how to go about proving that other dimensions really exist in the microcosm. The energies are so big that we cannot figure out how to build the necessary accelerators and instruments. We know that Mother Nature is rather frugal, so I would be very surprised if more than 4 dimensions existed.There have been many proposals since the 1920s to increase the number of dimensions to spacetime beyond the standard four that relativity uses. In all cases, these extra dimensions are vastly smaller than an atom and are not accessable to humans…fortunately!

Current string theory proposes 6 additional dimensions while M-theory allows for a seventh. These additional dimensions are sometimes called ‘internal degrees of freedom’ and are related to the number of fundamental symmetries present in the physical world at the quantum scale. The equations that physicists work with require these additional dimensions so that new symmetries can be defined that allow physicists to understand physical relationships between the various particle families.

They think these are actual, real dimensions to the physical world, only that they are now ‘compact’ and have finite sizes unlike our 4 dimensions of space and time which seem almost to be infinite in size. The figure above shows what these compact additional dimensions look like, mathematically. Each point in 4 dimensional space-time has another 6 dimensions attached to it which ‘particles and forces’ can use as extra degrees of freedom to define themselves and how they will interact with each other. These spaces are called Calabi-Yau manifolds and it is their 6-dimensional geometry that determines the exact properties of fundamental particles.

Do not confuse them with ‘hyperspace’ because the particles do not actually ‘move’ along these other dimensions. They are not ‘spatial’ dimensions, but are as unlike space and time as time is unlike space!

Cosmology

What facts disprove the Big Bang theory?

The current, seemingly comprehensive theory of the origin and evolution of our universe is called inflationary, big bang cosmology. This theory explains how our universe emerged from a singularity of high temperature and density and expanded and cooled. As it did so, space dilated at a faster-than-light pace and cooled so that the familiar elementary particles and forces could produce the cosmic background radiation and a variety of complex particles as the universe expanded. By about three minutes after the Big Bang, the ratio of hydrogen to helium had been cosmologically established, and so had the amount of cosmic background photons and neutrinos. In addition, during the rapid ‘inflation’ period, irregularities in the cosmic density of matter were established as well as a background of gravitational radiation.

The spectacular results of the WMAP satellite , along with the results from COBE and a number of other high-precision studies of the cosmic background radiation have now established that the universe is 13.7 billion years old, and that its space geometry is exactly ‘flat’. Also, according to the most recent WMAP ‘pie graph’ above, the amount of the gravitating matter in ordinary stars and gas is only 4.6%. The rest of the gravitating ‘mass’ of the observable universe is in the form of Dark Matter (24%), with an additional contribution of Dark Energy (71.4%). It is this Dark Energy that is causing our universe to expand at an accelerated pace, which has been observationally detected using distant supernovae.

There have been over the years several potential rivals to Big Bang cosmology, but with the exception of Steady State theory, none have attracted more than a handful of interested supporters. The reason is that they failed to predict, or offer explanations for, some basic observations that are widely agreed upon to be key tests of any cosmological theory, even by the rivals to Big Bang theory!

DeSitter Cosmology ca 1917 – The universe is presumed to be entirely empty of matter, but expands exponentially in time because of the presence of a non-zero cosmological constant. This refutes nearly every observational fact now available, including the actual rate of expansion which follows a linear, Hubble law, not an exponential expansion law with time. Also, the density of matter in the universe is not zero because we are here, and so are a lot of other stars and galaxies!

Einstein Static Cosmology ca 1917-The universe does not expand, and is static in time. The cosmological constant is precisely tuned to balance the attractive tendency of matter. Like DeSitter cosmology, it also fails to agree with modern observations, because the universe is expanding linearly with time. It is also unstable to the slightest perturbation in the value of this constant.

Lemaitre Cosmology ca 1924 – The universe started with a ‘big bang’ with no cosmological constant. The initial state was a giant radioactive atom containing all the matter in the universe near absolute zero. This theory agrees with the observed expansion, but fails to explain the existence of the cosmic background radiation and the universal abundances of hydrogen, helium and deuterium because it requires the decay of a single massive ‘super atom’ at the instant of the Big Bang.

Steady State Cosmology ca 1950 – Developed by Fred Hoyle and Thomas Gold, it proposes that the universe has been expanding for eternity and that new galaxies are created, atom by atom, in intergalactic space ‘out of empty space’. This theory had its heyday in the 1950’s and 1960’s, but was never able to explain convincingly where the cosmic background radiation came from, why it is so isotropic, and why its temperature is fixed at 2.7 K. It also provided no clues as to why there ought to be a universal abundance ratio for hydrogen, helium and deuterium.

Cold Big Bang Cosmology ca 1965 – Developed by David Layzer at Harvard, it proposes that the Big Bang occurred, but that the initial state was at absolute zero and consisted of a pure solid of hydrogen. This fragmented into galaxy-sized clouds as the universe expanded. It provided no explanation for where the cosmic background field came from and why it is isotropic and at a temperature of 2.7 K.

Hagedorn Cosmology ca 1968 – Physicist Robert Hagedorn proposed that all of the details of big bang theory are probably true, except that the early history of the universe had a limiting temperature of about 1 trillion degrees because the structure of matter has an infinite ladder of ‘fundamental particles’ out of which electrons, protons and neutrons are constructed. This has been refuted with the discovery that quarks exist which place any limiting temperature for the early history of the universe at temperatures well above 1000 trillion degrees.

Brans-Dicke Cosmology ca 1955 – Einstein’s equation for gravity in general relativity is modified to include a ‘scalar’ field. This field causes the value of the constant of gravity to change slowly over billions of years. This also leads to a modification of the early history of the universe. Experimental searches for a change in the constant of gravity show that it has not changed to within experimental error during the last 2 – 3 billion years. It would cause the evolution of the Earth-Moon system to be significantly altered, and the evolution of the Sun to be severly modified. Neither of these effects have been observed.

Old Inflationary, Big Bang Cosmology ca 1980 – Developed as a ‘toy’ model by Alan Guth in 1980. The Inflationary era which ended 10^-34 seconds after the Big Bang caused the nucleation of innumerable ‘bubbles’ of true vacuum which merged together to form a patina of matter and radiation in a very lumpy configuration. The cosmic background radiation, however, shows that the universe is very smooth to 1 part in at least 10,000 since about 300,000 years after the Big Bang. There is no evidence for such a turbulent and lumpy transition era.

Oscillatory Big Bang Cosmology ca 1930 – This a a possible modification to Big Bang cosmology that differs only in that the current expansion will be replaced by a collapse phase and then an expansion phase etc etc. There is no evidence that there was ever a prior expansion-collapse phase. The universe also does not seem to have enough matter to make it a ‘closed’ universe destined to recollapse in the future; an important requirement for any future oscillation cycle.

Big Bang Cosmology with added Neutrino Families ca 1970 – Big Bang cosmology is largely correct, except that to solve the ‘missing’ or ‘dark’ matter problem, new families of neutrinos have to be added to the universe. This would change the cosmological abundance ratios of helium and deuterium relative to hydrogen so that the current observed values no longer are possible. There is also no experimental evidence that more than 3 types of neutrinos exist; and these are already consistent with the measured cosmological abundances.

Chronometric Cosmology ca 1970 – Developed by I. Segal at MIT, it proposes that space-time has a different mathematical structure than the one that forms the basis for Big Bang cosmology. So far as we can tell, the major disagreement is in the rate of the expansion of the universe which comes out as a quadratic law between distance and expansion speed, rather than the linear Hubble Law. This proposal seems to be inconsistent with what has been observed for distant galaxies during the last 3-4 decades. There may be other disagreements with Big Bang cosmology, but Chronometric cosmology has not been explored deep enough to make testable predictions in these other areas.

Alfven Cosmology ca 1960 – Developed by physicist Hans Alfven, it proposes that the universe contains equal parts of matter and anti-matter. No explanation is made for many of the other observational facts in cosmology. If there were equal parts of matter and anti-matter, there ought to be regions in the universe where these were in contact to produce X-rays or gamma rays due to the annihilation process. No such large-scale background has ever been detected that can be attributed to proton or electron annihilation.

Plasma Cosmology ca 1970 – The matter in the universe, on the largest scales, is not neutral, but has a very weak net charge which is virtually undetectable. This causes electromagnetic forces to dominate over gravitational forces in the universe so that all of the phenomena we observe are not the products of gravitation alone. This is an intriguing theory, but other then denying their importance, it cannot easily explain the origin of the cosmic background radiation, its isotropy and temperature, and the abundances of helium and deuterium.

The basic observations that are agreed to me cosmological tests for any theory are:

1…. The universe is expanding. – This is a large-scale observation which spans the entire observable universe so it must be ‘cosmological’

2…. There exists a cosmic background radiation field detectable at microwave frequencies. – Why doesn’t it occur at other frequencies and only seen in the microwave region, covering every direction of the sky?

3…. The cosmic microwave background field is measurably isotropic to better than a few parts in 100,000 after compensation is made for the relativistic Doppler effect caused by Earth/Sun/Milky Way motion. – This is a large-scale property of this phenomenon that has nothning to do with the Milky Way or other galaxies so it must be a cosmological feature.

4…. The cosmic microwave background radiation field is precisely that of a black body. – Many other kinds of radiation are known, but NONE have exactly a black body spectrum. Only the cosmic background radiation is a perfect black body to the limits of our ability to measure its spectrum.

5…. The cosmic microwave background radiation field has a temperature of 2.7 K. – Why 2.7 K? Why not 5.019723 K. Only Big Bang cosmology predicts a relic radiation at a temperature near 3 degrees and not some other value.

6…. There does exist a universal abundance ratio of helium to hydrogen consistent with the current expansion rate and cosmic background temperature. – Whether we look at the compsition of stars, planets or even gas clouds in distant galaxies, we always seem to come upon a ‘universal’ constant ratio of helium to hydrogen and deuterium to hydrogen. There must be an explanation for this that has nothing to do with just our solar system or Milky Way.

7…. The cosmological abundance of deuterium relative to hydrogen and helium is consistent with the levels expected given the current expansion rate and density. – If the universe expanded faster, then there would be less time for heavier elements such as helium and deuterium to form.

8…. There are only three families of neutrinos. – Although we have not confirmed this to be true in the vicinity of distant galaxies, we do see the same kinds of elements and physics occurring out there, especially supernovae whose physics depend very sensitively upon the numbers of distinct types of neutrinos, and the constancy of the underlying ‘weak interaction’ physics.

9…. The night sky is not as bright as the surface of the Sun. – A simple but profound observation which can only be resolved by the correct distribution of stars in the universe, their ages, and the expansion of the universe.

10… The cosmic background radiation field is slightly lumpy at a level of one part in 100,000 to 1,000,000. – Why is this? And why by this amount?

11… There are no objects that have ages indisputably greater than the expansion age of the universe. – Our universe nearby does not seem to have very old stars older than 20 billion years even though their properties should be easily recognizable and a simple extension of the physics and evolution of the oldest stars we do see.

12… There are about 10,000,000,000 photons in the cosmic background radiation field for every proton and neutron of matter. – This is an important ‘thermodynamic’ number which tells us how the universe has evolved up to the present time. Why is its entropy so huge?

13… The degree of galaxy clustering observed is consistent with an expanding universe with a finite age less than 20 billion years. – A direct observation which again tells us that gravity has not had a long time to act to build up large complex structures in today’s universe.

14… There are no elements heavier than lithium which have a universal abundance ratio. – What process created these heavier elements?

15… The universe was once opaque to its own radiation. – This must follow from the black body shape of the cosmic background radiation.

16… The universe is now dominated exclusively by matter and not a mixture of matter and anti-matter. – Only a few contenders to Big Bang cosmology make any attempt at explaining this direct observation.

So there you have it. This is not a game of billiards where the cue ball (data) is carefully lined up so that Big Bang theory comes out looking inevitable. Any of these other theories have been repeatedly invited to take their best shot too, and the results are always the same. The proponents have to intervene to even get their theories to pony up a simple prediction for any of these cosmological data.

The biggest prediction of Big Bang cosmology lies in its very foundations. It is based on the inerrancy of general relativity and how this theory accounts for gravity under extreme conditions. Its basic predictions have been tested many times, and new exotic phenomena such as the Lenze-Thirring effect and gravity waves have also been predicted and confirmed by the theory. It seems to be a flawless explanation for how grfavity workd, but if it is accurate, then we need lots of Dark Matter and Dark Energy in the universe in addition to the 5% of stars and gas that we can see. That is the big problem.

Dark matter is found not only on the cosmic scale but in regions as small as galaxies. In fact it was discovered in galaxies long before WMAP made its first studies. Our own Milky Way seems to have six times more gravitating stuff orbiting its center than in all the luminous matter and gas clouds we can detect. In fact, any large systems of matter we have studied have this Dark MAtter problem. Some physicists have interpreted this as an actual breakdown in General Relativity itself, but their proponents cannot find an extension or replacement for general relativity that makes Dark Matter go away. Meanwhile, physicists have not detected any of the particle candidates for Dark matter at the Large Hadron Collider or other labs around the world.

So Dark Matter can be added to Big Bang cosmology, but we don’t yet know what kind of physical material it is, or whether there might be something subtly wrong with General Relativity itself.

Cosmology

Where in the universe did the Big Bang happen?

The Big Bang did not happen inside the 3-d space of our universe, at least that’s what our best understanding of physics seems to be telling us during the last 100 years! That means it did not happen ‘over there’ a billion light years beyond Antares.

The only guide we have for answering this question is Big Bang cosmology and Einstein’s general theory of relativity. These make very specific predictions for what happened to space and time during the Big Bang.

The figure above (Credit: Martin Kornmesser, Luis Calcada, NASA, ESA/Hubble) shows the expansion of the universe predicted by general relativity. Note that the latitude and longitude positions of the ‘star’ galaxies remains the same but the distance between them is dilating as the radius of the sphere increases. This is a representation of how our universe is expanding. From this geometric analogy, if the surface of the sphere represented the 3-d volume of our universe at a specific time since the big bang, you see that the volume of space is increasing but space isnt being added in from some where else! This is a sphere in 4-dimensions with a 3-d surface, in geometric analog to a 3-d basket ball with a 2-d surface. Also, as you shrink the sphere’s radius, the volume of 3-d space decreases steadily until it approaches the condition where the radius is zero. You can do this with a mathematical ‘balloon’ but not a real one. At zero radius we also have the condition where the 3-d volume of space also vanishes.

Now suppose that this spherical surface was filled with atoms. As you shrink the volume of space, the density of this matter increases steadily. When you get close to the time where the radius is zero, the average density of matter in the 3-d space of this sphere has grown enormously. When the radius becomes zero, the density becomes infinite and we have what physicists call a singularity.

So, the best, non-mathematical description that any cosmologist can create for describing the Big Bang is that it occurred in every cubic centimeter of space in the universe with no unique starting point. In fact, it was an event which our mathematics indicate, actually brought space and time into existence. It did not occur IN space at a particular location, because it created space ( and time itself) as it went along. There may have existed some state ‘prior’ to the Big Bang, but it is a state not described by its location in time or space. This state preceded the existence of our time and space.