Interstellar Travel?

Interstellar travel revolves around the answers to three major questions:

1) Where will we go?

2) What will we do when we get there?

3) How will it benefit folks back on Earth?

Far beyond the issue of whether interstellar travel is technologically possible is the very practical issue of answering these questions long before we turn the first screw in the hardware.

A few of the thousands of stars within 50 light years of Earth.(Credit: Atlas of the Universe)

In science fiction, finding new destinations is usually handled by either manned or unmanned expeditionary forces. Not surprisingly, the hazardous experiences of the manned expeditions are usually the exciting core of the story itself. When we create this technology ourselves, the first  trips are usually to a popular nearby star like Alpha Centauri (e.g Babylon 5). When we are co-opting alien technology, we often have to go to where the aliens previously had outposts often hundreds or thousands of light years away ( e.g Contact or Stargate). In any event, most stories assume that the travelers can select multiple destinations and hop-scotch their way around the local universe within a single human lifetime to find a habitable planet. Apparently, once you have convinced politicians to fund the first trip, the incremental cost of additional trips is very small!

The whole idea of interstellar travel was created by fiction writers, but because it has many elements of good science in it, it is a very persuasive idea. It is an idea located smack in the middle of the ‘gray area’ between fantasy and reality, and this is what goads people on to try to imagine ways to make it a reality. One thing we do know is that it will be an expensive venture requiring an investment at the level of many percent of an entire planet’s GDP.

By some estimates, the first interstellar voyage will cost many trillions of dollars, require decades to construct, and involve tens to hundreds of passengers and explorers. Assuming a project of this scope can even be sold to the bulk of humanity that will be left behind to pay the bills, how will the destination be selected? Will we just point the ship towards any star and commit these resources to a random journey and outcome, or will we know a LOT about where we are going before the fuel is loaded? Most of us will agree that the latter case for such an expensive ‘one of’ mission is more likely. By the way, let’s not talk about the human Manifest Destiny to explore the unknown. Even Christopher Columbus knew his destination in detail (India!) and traveled within a very benign biosphere, free breathable atmosphere and comfortable gravity to get there in a few months.

So…where will we go?

Contrary to popular ideas, we will know our destination in great detail long before we leave our solar system. We will know whether the star has any planets, and we will know it has at least one planet in its habitable zone (HZ) where temperature would allow liquid water to exist. We will know if the planet has an atmosphere or not. We will know its mass and size, and perhaps more importantly, whether the planet has a biosphere. We will not invest perhaps trillions of dollars to study a barren Mars or Venus-like planet. All of these issues will be worked out by astronomical remote-sensing research at far lower cost than traveling there. If a nearby star does not have detectable planets, we will most certainly NOT mount a trillion-dollar mission to just ‘go and see’!

The 10 nearest stars are: Proxima Centauri (4.24 lys), Alpha Centauri (4.36), Barnards Star (5.96), Luhman 16 (6.59), Wolf 359 (7.78), Lalande 21185 (8.29), Sirius (8.59), Luyten 726-8 (8.72), Ross 154 (9.68) and Ross 248 (10.32). This takes us out to a distance of just over 10 light years from Earth. The prospects for an interesting world to visit are not good.

Proxima Centauri has one recently-detected Earth-sized planet orbiting inside its HZ, making it a Venus-like world of no interest. Alpha Centauri B has one unverified Earth-sized planet, but not in the star’s liquid-water HZ. It orbits ten times closer than Mercury. There are no planets larger than Neptune orbiting this star closer than our planet Jupiter. Barnards Star has a no known planets, but a Jupiter-sized planet inside the orbit of Mars is exluded, so this is still a viable star for future searches for terrestrial planets in the star’s HZ. Luhman 16 is a binary system whose members orbit each other every 25 years at a distance of 3 AU. A possible companion orbits one of these stars every month at a distance closer than Mercury. As for the stars Wolf 359, Lalande 21185, Sirius, Luyten 726-8, Ross 154 and Ross 248, there have been searches for Jupiter-sized companions around these  stars, but none have ever been claimed.

So, our nearest stars within 10 light years are pretty bleak as destinations for expensive missions. There is no solid evidence for Earth-sized planets orbiting within the HZs of any of them. These would not be plausible targets because there is so little return on the high cost of getting there, even though that cost in terms of travel time is the smallest of all stars in our neighborhood. This also sets a scale for the technology required. It is not enough to visit our nearest star, but we have to trudge 2 to 3 times farther before we can find better destinations.

Better Destinations.

Let’s take a bigger step. Out to a distance of 16 light years there are 56 normal stars, which include some promising candidate targets.

Epsilon Eridani (10.52 ly) has one known giant planet outside its HZ. It also has two asteroid belts: one at about three times Earth’s distance from our sun (3 AU) and one at about 20 AU. No one would ever risk a priceless mission by sending it to a sparse planetary system with deadly asteroid belts and no HZ candidates!

Groombridge 34 (11.62 ly) –The only suspected planet has a mass of more than five Earths. No mission would be sent to such a planet for which an atmosphere would probably be crushingly dense and probably Jupiter-like even if it was in its HZ.

Epsilon Indi (11.82 ly) – has a possible Jupiter-sized planet with a period of more than 20 years. No known smaller planets.

Artist rendering of the planets Tau Ceti e and f (Credit: PHL @ UPR Arecibo)

Tau Ceti (11.88 ly) probably has five planets between two and six times Earth’s mass, and with periods from 14 to 640 days. Planet Tau Ceti f is colder than Mars and is at the outer limit to the star’s HZ. Its atmosphere might be dense enough for greenhouse heating, so the world might be habitable after all. But this is guesswork not certainty.

Kapteyn’s Star (12.77 ly) – It has two planets, Kapteyn b and Kapteyn c, that are 5 to 8 times the mass of Earth. Kapteyn b has a period of 120 days and is a potentially habitable planet estimated to be 11 billion years old. Again, a massive planet whose surface you could never visit, so what is the point of the interstellar expedition?

Gliese 876 (15.2 ly) has four planets. All have more than 6 times the mass of Earth and orbit closer than the planet Mercury. Gliese 876 c is a giant planet like Jupiter in the star’s habitable zone. Would you bet the entire mission that 876c has habitable ‘Galilean moons’ like our Jupiter? This would be an unacceptable shot in the dark, though a tantalizing one.

So, out to 15 light years we have some interesting prospects but no confirmed Earth-sized planet in its star’s HZ whose surface you could actually visit. We also have no solid data on the atmospheres of any of these worlds. None of these candidates seem worth investing the resources of a trillion-dollar mission to reach and study. We can study them all from Earth at far less cost.

Best Destinations.

If we take an even bigger step and consider stars closer than 50 light years we have a sample of potentially 2000 stars but not all of them have been discovered and cataloged. About 130 are bright enough to be seen with the naked eye. The majority are dim and cool red dwarf stars, which are still good candidates for planetary systems. In this sample we encounter among the known planetary candidates several that would be intriguing targets:

61 Virginis (11.41 ly) – It has three planets with masses between 5 and 25 times our Earth, crowded inside the orbit of Venus. The asteroidal debris disk has at least 10 times as many comets as our solar system. There are no detected planets more massive than Saturn within 6 AU. An Earth-mass planet in the star’s habitable zone remains a possiblity, but the asteroid belts make this an unacceptable high risk target.

Gliese 667 planets (Credit: ESO )

Gliese 667 (23.2 ly) –As many as seven planets may orbit this star, but have not been confirmed. All have masses between that of Earth and Uranus. All but one are huddled inside the orbit of Mercury. Planets c and d are in the star’s HZ and are at least 3 times the mass of Earth. Their hypothetical moons may be habitable.
55 Cancri (40.3 ly)- All five planets orbiting this star are more than five times the mass of Earth. Only 55 Cancri e is located at the inner edge of the star’s HZ and its hypothetical moons could be habitable. More planets are possible within the stable zone between 0.9 to 3.8 AU if their orbits are circular. This is a system we still need to study.

HD 69830 (40.7 ly) has a debris disk produced by an asteroid belt twenty times more massive than that in our own solar system. Three detected planets have masses between 10 to 18 times that of Earth. The debris disk makes this a high-risk prospect even if there are habitable moons.

HD 40307 (41.8 ly) Five of the six planets orbit very close to the star inside the orbit of Mercury. The fifth planet orbits at a distance similar to Venus and is in the system’s habitable zone. The planets range in mass from three to ten times Earth. Again, is a planet in its HZ with a mass too great for a direct human visit a good candidate? I don’t think so.

Upsilon Andromedae (44.25 ly) The two outer planets are in orbits more elliptical than any of the planets in the Solar System. Upsilon Andromedae d is in the system’s habitable zone, has three times the mass of Jupiter, with huge temperature swings. Its hypothetical moons may be habitable.

47 Ursa Majoris (45.9 ly) The only known planet 47 Ursae Majoris b is more than twice the mass of Jupiter and orbits between Mars and Jupiter. The inner part of the habitable zone could host a terrestrial planet in a stable orbit. None yet detected.

There are still many more stars in this sample to detect, catalog and study so it is possible that a Goldilocks Planet could be found eventually. But we are now looking at destinations more than 20 light years away at a minimum. This will considerably increase the cost and duration of any interstellar mission by factors of five to ten times a simple jaunt to Alpha Centauri.

Other issues.

Would you really consider a planet with two to five times Earth’s gravity to be a candidate? Who would want to live under that crushing weight? Many of the candidates we have found so far are massive Earth’s that few colonists would consider standing upon. Their surfaces are also technologically expensive to get to and leave. But perhaps these worlds might have moons with more comfortable gravities? There is always hope, but will that be enough to risk a multi-trillion-dollar mission?

There is also the issue of atmosphere. None of the candidate planets we have discussed transit their stars, so we cannot detect their atmospheres and figure out if they have atmospheres and if their  trace gases would be  lethal. The perfect destination worth the expense of a trip would have a breathable atmosphere with oxygen. Since free oxygen is only produced by living systems, our target planet would have a biosphere. We can only hope that as the surveys of the nearby stars continue, we will find one of these. But statistics suggests we will have to search much farther than 50 light years and a few thousand stars before we encounter one. That makes the interstellar voyage even more costly, not by factors of five and ten, but potentially hundreds of times. But if the trip were to a world with a known biosphere, THAT might be worth the effort, but possibly nothing less than this would be worth the cost, the risk, and the scientific return.

So the bottom line is that the only interstellar destination worth the expense is either one in which colonists can live comfortably on the planet with a lethal atmosphere, hermetically sealed under a dome, or a similar planet with a breathable oxygen atmosphere and a biosphere. Statistically, we will find far more examples of the first kind of target than the second. But in the majority of the cases, we will not be able to detect the atmosphere of an Earth-sized world in its habitable zone before we start the trip, and will have to ‘guess’ whether it even has an atmosphere at all!

The enormous cost of an interstellar trip to a target tens or even hundreds of light years away will preclude any guess work about what we will find when we get there. Consider this: Investing $100 billion to travel to Mars, a low-risk planet we thoroughly understand in detail, is still considered a political pipe dream even with existing technology! What would we call a trip that costs perhaps 100 times as much?

For more on this topic, have a look at my book ‘Interstellar Travel:An astronomer’s guide’. Available at


Return here for my next blog posting on Friday, February   3

The Anti-science War

This blog will highlight some of the current battle lines, and also describe the heroic measures now being formulated and implemented to fight this War on Reason.

We have all heard about President Trump’s penchant for making up facts and pushing them out to his followers, but this blog series is not about that on-going, and unprecedented, problem. Since Day 1, this administration has begun the process of actively (or by accident!) suppressing scientists who are working in politically uncomfortable fields such as climate change and Earth science. This is only the beginning of what will be a long battle against clarity and reason.


Bad News Bullets.

January 25 – The Trump administration has told the EPA to remove its climate change data from its website (The Business Insider)

January 24 – Badlands National Park deletes tweets on climate change(CNN)

January 24 – Trump imposes gag order on EPA and USDA (USUNCUT)

January 24 – Trump Administration Restricts News from Federal Scientists at USDA, EPA (Scientific American)

January 23 – EPA freezes grants. Tells employees not to talk about it – (Huffington Post)

January 23 – CDC abruptly cancels long-planned conference on climate change and health (The Washington Post)

January 20 – White House Office of Science and Technology climate change webpage disappears after Trump’s inauguration (The Hill)

December 20 – Canadian Scientists Warn U.S. Colleagues: Act Now to Protect Science under Trump (Scientific American)

December 13 – Scientists are frantically copying U.S. climate data, fearing it might vanish under Trump (The Washington Post)

November 23 – Trump adviser proposes dismantling NASA climate research (Chicago Tribune)

October 30 – Trump takes aim at NASA’s climate budget (The Hill)

May 15 – House Budget Cuts NASA Earth Science By More Than $250 Million  (SpaceNews)


Good News Bullets

January 26 – CDC’s canceled climate change conference is back on — thanks to Al Gore (Washington Post)

January 26 – NPS Climate Change website still online (

January 26 – National Park Service staff escalate campaign against Trump – No one from the Trump administration has complained or asked them to remove the posts – (CBSnews)

January 26 – USDA Office of Chief Economist – climate change report still online (

January 26 – EPA climate change website still online (

January 26 – The Department of Energy Climate and Environmental Science Division webpage is still online (

January 25 – USDA scrambles to ease concerns after researchers were ordered to stop publishing news releases (Washington Post)

January 25 – Scientists planning their own march on Washington (CNN)

January 25 – Report: Trump Team Backtracks On Order To Remove EPA Climate Site (InsideEPA)

January 25 – NASA scientists join resistance with rogue Twitter account @rogueNASA with over 27,000 followers. (USUncut)

January 25 – National Park Service employees set up rogue twitter account to disseminate climate change information @AltNatParkSer (USUncut)

January 25 – EPA employees set up rogue twitter account to disseminate science @AltUSEPA (USUncut)

January 24 – Badlands NPS goes on climate change tweetstorm (USAToday)

January 24 – People’s Climate March being organized for April 29 in Washington DC.  (

January 24 – USDA disavows gag-order emailed to scientific research unit (Reuters)

January 24 – March for Science starts organizing on Facebook with 500,000 registrants in 24 hours – #ScienceMarch #ScienceResists #USofScience (MarchForScience)

January 24 – Trump’s pick to lead Commerce Department says NOAA scientists can freely share their work (Washington Post)

January 10 – NASA Earth science director expects short-term budget stability (for FY17: The division received $1.92 billion in 2016, and requested $2.03 billion for 2017) – (SpaceNews)

December 28 – Earth scientists are freaking out. NASA urges calm. (SpaceNews)

Bookmark this blog for future updates as new news develops!




We have been here before.

In Nazi Germany of the 1930s, Deutsche Physik swept the German science community and Einstein’s relativity was denounced as Jewish Physics and banned from the classroom and social discourse. If you think I am making a mountain out of a mole hill in worrying about president Trump’s recent edicts, you are delusional.

First he expunged all mention of climate change from the White House website, then he forced the US Forest Service to take down its climate change facts, finally he has suppressed the USDA and NIH from posting new public content, and placed a freeze on research funding pending this administration’s evaluation.
He has threatened to de-fund all of Earth Science research at NASA, and I am sure that once the new NASA administrator has been appointed by Trump, we will see changes in the public content at NASA with no mention of climate change or the annual evaluations of global warming trends. These institutions are political, top-down systems in which what the Administrator says becomes law within each institution and scientists have no real recourse to protest pull backs in what they can post online, or even whether they can get travel authorization to attend important conferences. We will soon see whether Trump forces NASA to abide by the same gag orders he is placing on other research institutions across the federal government.

We can sit back and profess caution, with the hope that clearer GOP minds in Congress will prevail, but the moral ineptitude of the GOP party in the face of Trump has been a cautionary tale these last few weeks. The calculus is already being performed behind closed doors that any source of information contradicting Trump’s delusions will be strongly restrained. It is not out of the question that entire research grant areas will vanish overnight. I even wonder about the security of our armada of Earth research satellites, which are supported by budget ‘line items’ and can be terminated by Congress even as they are taking invaluable historic data proving the case for climate change. Weather satellites, of course, will be maintained because the GOP owns lots of property across the USA whose assets need protection.

So what to do?

For one, join EVERY march you hear about whether it relates to science or not. Show your solidarity with all other organizations that are marching to protest the new policies. Even now, Scientists March on Washington is starting to organize .It went from 200 members last night to over 30,000 by morning’s light the next day! Some worry that it will be ‘hijacked’ by other causes, but the goal is to show huge participant numbers to make the evening news and to really piss off Trump. So embrace your LGBT, Women’s, and all other groups, many of whom are themselves scientists or science literate members of the public!

Facebook page:


Washington Post:

UK Telegraph:
Daily KOS:

Check back here on Monday January 30  for a new blog!

Running on Empty

I don’t think that many people realize that right now, but a few miles north of Geneva, Switzerland and a few hundred meters below the sleepy, bucolic countryside, a leviathan machine 27 km in diameter works round-the-clock to recreate a glimpse of the Big Bang.

Called the Large Hadron Collider (LHC) it is the world’s largest particle collider created in 1998-2008 by a collaboration of over 10,000 scientists and engineers from over 100 countries. It cost $13 billion dollars, and consumes 1 billion kilowatt-hours of electricity each year; enough to run a city of 300,000 homes!

The aim of the LHC is to allow physicists to test the predictions of different theories of particle physics, including measuring the properties of the Higgs boson and searching for the large family of new particles predicted by supersymmetric theories, as well as other unsolved questions of physics.

Since it began full-power operation in 2009, it has made a series of major discoveries that have rocked the physics world. The first of these, some 50 years after its prediction, was the discovery in 2012 of the Higgs Boson; a missing particle in the Standard Model that imbues most particles with their masses. Two years later, two new heavy sub-atomic particles were discovered called the Xi-prime and the Xi-star. Each consists of a bottom-quark, a down-quark and a strange-quark. Then a four-quark particle called the Z(4430) was found in 2014, along with signs of a five-quark combination that decayed into other, more stable particles. By 2016, LHC physicists had detected the light from antimatter hydrogen atoms (an anti-proton orbited by a positron). The findings were that this light was exactly the same as from a normal-matter hydrogen atom, so you really can’t tell the difference between matter and anti-matter from the light it emits!

But there was one other search going on that hasn’t been quite as successful, and with serious consequences.
Since 1978, physicists have explored the mathematical wonders of a new symmetry in nature called supersymmetry. This one shows how the particles that carry forces in the Standard Model (photons, gluons, w-bosons) are related to the matter particles they interact with (electrons, neutrinos, quarks). This symmetry unifies all of the known particles in the Standard Model, and also predicts that all normal particles will have supersymmetry partners with far-higher masses. The electron has a partner called the slectron. The quark has a partner called the squark, and so on. The simplest change in the Standard Model that includes this new mathematical symmetry ( called the Minimal Supersymmetric Standard Model or MSSM) adds 12 new matter particles and 12 new force particles beginning at masses that are 3 times greater than the mass of the normal proton. Amazingly, one of these partners to the normal-matter neutrinos would exactly fit the bill for the dark matter that astronomers have detected across the universe! MSSM predicts the eventual unification of all three forces; electromagnetism, strong and weak. MSSM would also let us accurately predict what happened before the universe was a microsecond old after the Big Bang!

Unfortunately, the search for any signs of supersymmetry particles is not going so well after seven years of sifting through data.

In one strategy, physicists look for any signs that the predictions made by the Standard Model are not accurate as a sign of New Physics. In another strategy, physicists look for the specific signs of the decays of these new, massive particles into the familiar matter particles.

On 8 November 2012, physicists reported on an experiment seen as a “golden” test of supersymmetry by measuring the very rare decay of the Bs meson into two muons. Disconcertingly, the results matched those predicted by the Standard Model rather than the predictions of many alternate versions of the Standard Model with supersymmetry included. New data with the collider now operating at higher energies than ever before, 13 trillion electron volts; 13 TeV) show no traces of superpartners.

As of the start of 2017, it really does look as though the LHC has given us a complete and well-tested Standard Model including the Higgs Boson, but has refused to hand over any signs of new particles existing between 190 GeV and 2,500 GeV (see the predicted particle plot below). This represents a distressing, barren desert which, had it looked as supersymmetry had predicted, should have been filled with dozens of new particles never before seen.

Many physicists are adopting an attitude of “keep calm and carry on.” “I am not yet particularly worried,” says theoretical physicist Carlos Wagner of the University of Chicago. “I think it’s too early. We just started this process.” The LHC has delivered only 1 percent of the data it will collect over its lifetime. But if no firm evidence is found for supersymmetry with the LHC, that also spells the end of another marvelous, mathematical theory that proposes to also unify gravity with the Standard Model. You know this theory by its popular name String Theory.

So a lot is still to come with the LHC in the next 5 years, and in no way is the current machine ‘running on empty’! Even its failure to find new physics will be revolutionary in its own right, and force an exciting re-boot of the entire theoretical approach in physics during the 2020s and beyond.

Check back here on Thursday, January 26 for the next blog!

The Rush to Mars

Even at the start of NASA’s space program in 1958, the target of our efforts was not the moon but Mars. The head of NASA, Werner von Braun was obsessed with Mars, and his Mars Project book published in 1948, was the blueprint for how to do this, which he revised in 1969. He saw the development of the Saturn V launch vehicle as the means to this end.

A major effort running in parallel with Kennedy’s moon program was the development of nuclear rocket technology. This would be the means for getting to Mars in the proposed expedition launch in November, 1981. The program was abandoned in 1972 when President Nixon unceremoniously canceled the Apollo Program and stopped the production of Saturn Vs. That immediately put the kibosh on any nuclear propulsion efforts because the required fission reactors were far too heavy to be lifted into space by any other means. He resigned from NASA once he realized that his dream would never be realized, and died five years later.

Flash forward to 2004 when President George Bush announced his Space Exploration Initiative to include a manned trip to Mars by the 2030s. There would be manned trips to the moon by 2015 to test out technologies relevant to the Mars trip and to learn how to live there for extended periods of time.

By 2008, the lunar portion of this effort was canceled, however the development of the Orion capsule and what is now called the Space Launch System were the legacies of this program still in place and expected to be operational by ca 2019. The rest of the Initiative is now called NASA’s Journey to Mars, and lays out a detailed plan for astronauts learning how to work farther and farther from Earth in self-sustaining habitats, leading to a visit to Mars in the 2030s. Meanwhile, the International Space Station has been greatly extended in life to the mid-2020s so we can finally get a handle on how to live and work in space and solve the many medical issues that still plague this environment.

However, NASA’s systematic approach is not the only one in progress today.

The entire foundation of Elon Musk’s Space-X company is to build and make commercially profitable successively larger launch vehicles leading to the Interplanetary Transport System which will bring 100 colonists at a time to the surface of Mars in about 80 days starting around 2026. Space-X is even partnering with NASA for a sample return mission called Red Dragon in ca 2018. Meanwhile, a competing program called Mars One (see picture above) proposes a crew of four people to land in 2032 with additional crew delivered every two years. . This will be a one-way do-or-die colony, and loss of life is expected. Mars One consists of two entities: the not-for-profit Mars One Foundation, and the for-profit company Mars One Ventures with CEO Bas Lansdorp at the corporate helm.

But wait a minute, what about all the non-tech issues like astronaut health and generating sustainable food supplies? Astronauts have been living in the International Space Station for decades in shifts, and many issues have been identified that we would be hard pressed to solve in only ten more years. NASA’s go-slow approach may be the only one consistent with not sending astronauts to a premature death on mars, with all the political and social ramifications that implies.

The dilemma is that slow trips to Mars, like the 240-day trips advocated by NASA’s plan exacerbate health effects from prolonged weightlessness including bone loss, failing eyesight, muscle atrophy and immune system weakening. These effects are almost eliminated by much shorter trips such as the 80-day target by Space-X. In fact, the entire $100 billion International Space Station raison de etra is to study long term space effects during these long transits. This existential reason for ISS would have been eliminated had a similar investment been made in ion or nuclear propulsion systems that reduced the travel time to a month or less!

Ironically, Werner von Braun knew about this as long ago as 1969, but his insights were dismissed for political reasons that led directly to our confinement to low Earth orbit for the next 50 years!

Check back here on Sunday, January 22 for the next installment!

The first named human

Not surprisingly, the record of the first humans identified by a personal name goes back to before the dawn of history itself. Through his artistic ‘Love Symbol’, the The Artist Formerly Known as Prince gave us a clue how pre-writing names were probably rendered!

Example of Jiahu Symbols (Wikipedia)


Pottery shards and other artifacts uncovered in China often bare curious symbols dating from the dawn of Chinese writing between 6600 and 6200 BC. Called Jiahu Symbols, they are not part of a written language but merely personally-invented symbols scratched on pottery to mark ownership by a specific individual: In other words a name!


The first recorded name given in an actual writing system can be found on clay tablets dating from the Jemdet Nasr period in Sumeria between 3200 and 3101 BC.

Example of Jemdet Nasr cuneiform (Credit: Metropolitan Museum of Art)

The tablets are not profound treatises on human thinking, but accounting ledgers for tallying up goods and possessions! Some of the first names are those of the slave owner Gal-Sal and his two slaves Enpap-x and Sukkalgir (3200-3100 BC). Another name is that of Turgunu Sanga (3100 BC) who seems to have been an accountant for the Turgunu family. There are many more names from this period but none that appear much before 3200 BC.



Example of Iry-Hor’s name on a pottery shard (Credit:Wikipedia)

Looking to Egypt, Iry-Hor (The Mouth of Horus) would be the earliest name we know dating from about 3200 BC. Little is known about Iry-Hor other than his name found on pottery shards in one of the oldest tombs in Abydos, though based on his burial he was a pre-dynastic pharaoh of Upper Egypt. [Wikipedia]. King Ka, from around this same time, was the first to inscribe his name inside a box-shaped serekh as an indicator of kingship. Following king Ka and king Iry-Hor we also have kings with hieroglyphic symbols of Crocodile King and Scorpion Kingfollowed by the name of the first pharaoh, Narmer (Catfish King), who united both Upper and Lower Egypt and together with his wife Neithhotep, lived between 3150 and 3125 BC. She, by the way, is the oldest women to be mentioned by name. The name Neithhotep means “[The Goddess] Neith is satisfied”.

Other civilizations arrive at writing names much later than the Chinese, Sumerians and Egyptians, but we can still ask the same question.


Anitta (no known meaning to the name) was the king of the Hittite city of Kussara. He lived around 1700 BC and is the earliest known ruler to compose a text in the Hittite language, which is the oldest known Indo-European text.

Linear B is a syllabic script that predates the Greek alphabet by several centuries. The oldest writing dates to about 1450 BC. Some Knossos Linear B tablets mention people by name. A number of Mycenian names have exact equivalents in Homer such as Hektor , which means “holding fast”.

Following many other ancient naming traditions, even ancient Greek names have an intrinsic meaning. For example Archimedes means “master of thought”, from the Greek element (archos) “master” combined with (medomai) “to think, to be mindful of”. And of course nearly all ancient Egyptian names have a separate meaning such as Amun Tut Ankh whose heiroglyphic name can be directly transcribed with the words ‘Amun’s Image Living’. We know him more popularly as Tutankamun.


The Mayans rose to prominence around A.D. 250. The oldest clearly named king is given by a glyph that translates into Yax Ehb’ Xook which literally means “First Step Shark”. He was the first king of Tikal who ruled sometime between 63 and 90 AD. Much later in 420 AD we have the purported founder of Copan, K’inich Yax K’uk’ Mo whose name means “Sun-Eyed Resplendent Quetzal Macaw”.
The peoples of Africa, Australia and North America all had spoken languages but not written symbolism, so until writing was imported to these areas we have no documentable record of names. For example among Native Americans, the oldest known name dates from the arrival of the Pilgims and their historical record-keeping. We read about Tisquantum (meaning The Wrath of God) ca 1620 AD who was a member of the Patuxet tribe. In Africa, there are many names that have come forward in time literally by word of mouth, but no way to establish their actual dates of usage through writing. For example, the legendary Queen of Sheba (1005-955 BC) was traditionally believed to be a part of the Ethiopian dynasty established in 1370 BC by Za Besi Angabo. Among Australian Aboriginals, writing only appeared after the arrival of Europeans in ca 1780s who transcribed language sounds into Latin text. Some of their names include Tharah, which means ‘thunder’ or Mokee which means ‘cloudy’.

What is interesting about almost all ancient human names is that in their own languages they actually mean something. They are not sterile monikers. At a cocktail party a conversation between two ancient Egyptians would be ‘Hi, my name is Living Image of Amun’…Pleased to meet you! My name is The Beautiful One Has Come!” It would not be heard as ‘Hi, my name is Tutankhamun…Pleased to meet you! My name is Nefertiti!”

This widespread human habit of naming people by phrases is far different than what we experience in modern times. We rarely think too much about names like ‘John Cartwright’, or Mike Brown. My own Swedish name, Sten Odenwald, translates into ‘Stone of Oden’s Forest’, and occasionally I really do think of it as more than a set of sounds or letters that designate me.

So the next time you visit Starbucks, imagine having this conversation:
You: I’d like a vente hot chocolate with whipped cream.
Barrista: Your Name?
You: The Living Image of the Irridescent Higgs Field
Barrista: ??
You: Just call me Bob.

Check here on Tuesday, January 17 for the next blog!

2016: A Year Beyond Reason

Psychologists define Cognitive Dissonance as the anxiety (dissonance) felt when people are confronted with information that is inconsistent with their beliefs. If the dissonance is not reduced by changing one’s belief, the dissonance can result in restoring consonance through misperception, rejection or refutation of the information, seeking support from others who share the beliefs, and attempting to persuade others.

In other words, humans can often carry two completely conflicting ideas in their consciousness at the same time. This is a stressful condition, and to alleviate it, we resort to rejecting contrary information, or try to persuade others of the consistency of our viewpoint.

We saw a lot of this condition in 2016!

This is not some liberal psychological plot to disparage the far-right of our political spectrum, but an objective fact of how our brains work. Researchers using functional Magnetic Resonance Imaging (fMRI) have found that cognitive dissonance activated specific brain regions called the dorsal anterior cingulate cortex and the anterior insular cortex. They also found that the more the anterior cingulate cortex signaled a conflict, the more dissonance a person experiences. During decision-making processes where the participant is trying to reduce dissonance, activity increased in the right-inferior frontal gyrus, medial fronto-parietal region and ventral striatum, while activity decreased in the anterior insula. Researchers concluded that rationalization activity, where you are trying to reduce the stress caused by cognitive dissonance, may take place quickly (within seconds) without conscious deliberation, and that the brain may engage emotional responses in the decision-making process.

The problem is that CD leads to other kinds of things that are sometimes harder to discern objectively. Confirmation bias refers to how people read or access information that affirms their already established opinions, rather than referencing material that contradicts them. This bias is particularly apparent when someone is faced with deeply held beliefs, i.e., when a person has ‘high commitment’ to their attitudes. People display confirmation bias when they gather or remember information selectively, or when they interpret it in a biased way. The effect is stronger for emotionally charged issues and for deeply entrenched beliefs. People also tend to interpret ambiguous evidence as supporting their existing position.

We saw a lot of that, too, in 2016.

An interesting study of biased interpretation occurred during the 2004 U.S. presidential election and involved participants who reported having strong feelings about the candidates. They were shown apparently contradictory pairs of statements, either from George W. Bush, John Kerry or a politically neutral public figure. They were also given further statements that made the apparent contradiction seem reasonable. From these three pieces of information, they had to decide whether or not each individual’s statements were inconsistent. There were strong differences in these evaluations, with participants much more likely to interpret statements from the candidate they opposed as contradictory. The participants made their judgments while in an fMRI scanner that monitored their brain activity. As participants evaluated contradictory statements by their favored candidate, emotional centers of their brains were aroused. This did not happen with the statements by the other figures. The experimenters inferred that the different responses to the statements were not due to passive reasoning errors. Instead, the participants were actively reducing the cognitive dissonance induced by reading about their favored candidate’s irrational or hypocritical behavior.

The bottom line is that, thanks to evolution, we have been blessed with a brain that suffers from many different kinds of reasoning pathologies. These may have had survival value in the remote past for making quick judgments in our social groups, or mistaking a distant shadow for a tiger, but now they are liabilities in our far more rational world of science and technology. Scientists spend a lot of time trying to weed out CD and CB from their analyses, and the result is that for 400 years of observing Nature as dispassionately as we can, we have created a marvelously accurate model of our world.

Sadly, CD and CB have at the same time been used to manipulate voters and consumers, with amazing negative consequences. The dissonance is that we fully realize that we are being manipulated by biased information, yet we seem powerless to resist its sirean call. In the current election, voters supporting Trump steadfastly refused to use his frequent and documented lying as grounds for not trusting him.

Some of the worst cases of CD and CB occurred during the 2016 election, and psychologists will be writing papers about it for decades. It all comes down to how people were convinced not to vote in their own self-interest.

How is it that voters whos only insurance came from the ACA voted for a GOP ticket that promised to repeal it? How is it that so many students voted against the democratic candidate who promised to eliminate tuition? How is it that so many poor people voted for an aledged multi-billionaire whose lavish gold-plated lifestyle was the antithesis of a poor person’s lifestyle?  How is it that Clinton and Trump were placed on the same ‘untrustworthy’ pedestal, when evidence showed that Clinton played by the rules and released her income tax statements, while Trump ran a Trump University con job and withheld his?  How is it that Trump’s steadfast attacks against our own intelligence service to defend Putin and Assange are not met with more rejection and patriotic contempt by his followers?

In the end, Trump voters and Red States will be paying a disproportionate economic penalty for letting CD and CB get the better of their reasoning. But because we are all in this together for the next four years, the rest of us will also feel some of this dissonance as well as collateral damage as voters in the red states ask voters in the blue states to bail them out.

Check back here on Saturday, January 14 for the next installment!

Space Travel via Ions

For 60 years, NASA has used chemical rockets to send its astronauts into space, and to get its spacecraft from planet to planet. The huge million-pound thrusts sustained for only a few minutes were enough to do the job, mainly to break the tyranny of Earth’s gravity and get tons of payload into space. This also means that Mars is over 200 days away from Earth and Pluto is nearly 10 years. The problem: rockets use propellant (called reaction mass) which can only be ejected at speeds of a few kilometers per second. To make interplanetary travel a lot zippier, and to reduce its harmful effects on passenger health, we have to use rocket engines that eject mass at far-higher speeds.

In the 1960s when I was but a wee lad, it was the hey-day of chemical rockets leading up to the massive Saturn V, but I also knew about other technologies being investigated like nuclear rockets and ion engines. Both were the stuff of science fiction, and in fact I read science fiction stories that were based upon these futuristic technologies. But I bided my time and dreamed that in a few decades after Apollo, we would be traveling to the asteroid belt and beyond on day trips with these exotic rocket engines pushing us along.

Well…I am not writing this blog from a passenger ship orbiting Saturn, but the modern-day reality 50 years later is still pretty exciting. Nuclear rockets have been tested and found workable but too risky and heavy to launch.  Ion engines, however, have definitely come into their own!

Most geosynchronous satellites use small ‘stationkeeping’ ion thrusters to keep them in their proper orbit slots, and NASA has sent several spacecraft like Deep Space-1, Dawn powered by ion engines to rendezvous with asteroids. Japan’s Hayabusha spacecraft also used ion engines as did ESA’s Beppi-Colombo and the LISA Pathfinder. These engines eject charged, xenon atoms ( ions) to speeds as high as 200,000 mph (90 km/sec), but the thrust is so low it takes a long time for spacecraft to build up to kilometer/sec speeds. The Dawn spacecraft, for example, took 2000 days to get to 10 km/sec although it only used a few hundred pounds of xenon!

But on the drawing boards even more powerful engines are being developed. Although chemical rockets can produce millions of pounds of thrust for a few minutes at a time, ion engines produce thrusts measured in ounces for thousands of days at a time. In space, a little goes a long way. Let’s do the math!

The Deep Space I engines use 2,300 watts of electrical energy, and produced F= 92 milliNewtons of thrust, which is only 1/3 of an ounce! The spacecraft has a mass of m= 486 kg, so from Newton’s famous ‘F=ma’  we get an acceleration of a= 0.2 millimeters/sec/sec. It takes about 60 days to get to 1 kilometer/sec speeds. The Dawn mission, launched in 2007 has now visited asteroid Vesta (2011) and dwarf planet Ceres (2015) using a 10 kilowatt ion engine system with 937 pounds of xenon, and achieved a record-breaking speed change of 10 kilometers/sec, some 2.5 times greater than the Deep Space-1 spacecraft.

The thing that limits the thrust of the xenon-based ion engines is the electrical energy available. Currently, kilowatt engines are the rage because spacecraft can only use small solar panels to generate the electricity. But NASA is not standing still on this.


The NEXIS ion engine was developed by NASA’s  Jet Propulsion Laboratory, and this photograph was taken when the engine’s power consumption was 27 kW, with a thrust of 0.5 Newtons (about 2 ounces).

An extensive research study on the design of megawatt ion engines by the late David Fearn was presented at the Space Power Symposium of the 56th International Astronautical Congress in 2005. The conclusion was that these megawatt ion engines pose no particular design challenges and can achieve exhaust speeds that exceed 10 km/second. Among the largest ion engines that have actually been tested so far is a 5 megawatt engine developed in 1984 by the Culham Laboratory. With a beam energy of 80 kV, the exhaust speed is a whopping  4000 km/second, and the thrust was 2.4 Newtons (0.5 pounds).

All we have to do is come up with efficient means of generating megawatts of power to get at truly enormous exhaust speeds. Currently the only ideas are high-efficiency solar panels and small fission reactors. If you use a small nuclear reactor that delivers 1 gigawatt of electricity, you can get thrusts as high as 500 Newtons (100 pounds). What this means is that a 1 ton spacecraft would accelerate at 0.5 meters/sec/sec and reach Mars in about a week!  Meanwhile, NASA plans to use some type of 200 kilowatt, ion engine design with solar panels to transport cargo and humans to Mars in the 2030s. Test runs will also be carried out with the Asteroid Redirect Mission ca 2021 also using a smaller 50 kilowatt solar-electric design.

So we are literally at the cusp of seeing a whole new technology for interplanetary travel being deployed. If you want to read more about the future of interplanetary travel, have a look at my book ‘Interplanetary Travel: An astronomer’s guide’, which covers destinations, exploration and propulsion technology, available at

Stay tuned!

Check back here on Wednesday, January 11 for the next installment!

Image credits:

Ion engine schematic

Star Destroyer

Why NASA needs ARMs

In 2013, a small 70-meter asteroid exploded over the town of Chelyabinsk and injured 3000 people from flying glass. Had this asteroid exploded a few hours earlier over New York City, the flying glass hazard would have been lethal for thousands of people, sending thousands more into the emergency rooms of hospitals for critical-care treatment. Of all the practical benefits of space exploration, it is hard to argue that asteroid investigations are not a high priority above dreams of colonization of the moon and Mars.

So why is it that the only NASA mission to actually try a simple method to adjust the orbit of an asteroid cannot seem to garner much support?

There has been much debate over the next step in human exploration: whether to go back to the moon or take the harder path to Mars. The later goal has been much favored, and for the last decade or so, NASA has developed a step-by-step Journey to Mars approach for doing this, beginning with the development of the SLS launch vehicle, and the testing out of many necessary systems, technologies and strategies to support astronauts making this trip, both quickly and safely. Along with numerous Mars mapping and rover missions now in progress or soon to be launched, there are also technology development missions to test out such things as solar-electric ‘ion’ propulsion systems.

One of these test-bed missions with significant scientific returns is the Asteroid Redirect Mission to be launched in ca 2021 for a cost of about $1.4 billion. NASA’s first-ever robotic mission will visit a large near-Earth asteroid, collect a multi-ton boulder from its surface, and use it in an enhanced gravity tractor asteroid deflection demonstration. The spacecraft will then redirect the multi-ton boulder into a stable orbit around the moon, where astronauts will explore it and return with samples in the mid-2020s.

But all is not well for ARM.

ARM was proposed in 2010 during the Obama Administration as an alternative to the canceled Constellation Program proposed by the Bush Administration, so with the new GOP-dominated administration set on dismantling all of the Obama Administrations’ legacy work, there is much incentive to eliminate it for political reasons alone.

Reps. Lamar Smith (R-Texas), chairman of the HCSST, and Brian Babin (R-Texas), chairman of the HSST space subcommittee reportedly feel that the incoming Trump administration should be “unencumbered” by decisions made by the current one — like what they want to do with the ACA . They claim to have access to “honest assessments” of ARM’s value rather than “farcical studies scoped to produce a predetermined outcome.” The House’s version of the 2017 FY appropriations bill includes wording that would force NASA to fully defund the ARM program. Furthermore, Smith and Babin wrote, “the next Administration may find merit in some, if not all, of the components of ARM, and continue the program; however, that decision should be made after a full and fair review based on the merits of the program and in the context of a larger exploration and science strategy.” Similar arguments will no doubt be used to cancel climate change research, which has also been deemed politically biased and unscientific by the current, incoming administration.

But ARM is no ordinary ‘exploration and science’ space mission, even absent its unique ability to test the first high-power ion engines for interplanetary travel, and retrieve a large, pristine multi-ton asteroid sample. All other NASA missions have certainly demonstrated their substantial scientific returns, and this is often the key justification that allows them to proceed. Mission technology also affords unique tech spinoff opportunities in the commercial sector that makes the US aerospace industrial base very happy to participate. But these returns all seem rather abstract, and for the person-on-the-street rather hard to appreciate.

For decades, astronomers have been discovering and tracking 100s of thousands of asteroids. We live in an interplanetary shooting gallery, where some 15,000 Near Earth Objects have already been discovered, and 30 new ones added every week. NEOs, by the way, are asteroids that come within 30 million miles of Earth’s orbit. These asteroids measure 1 kilometer or more, and statistically over 90% of this population has now been identified. But only 27% of those 140 meters or larger have been discovered. Once their orbits are determined, we can make predictions about which ones will pose an danger to Earth.

Currently there are 1,752 potentially hazardous asteroids  that come within 5 million miles of Earth (20 times Earth-moon distance). There are none predicted to impact Earth in the next 100 years. But new ones are found every week, and between now and February 2017, one object called 2016YJ about 30 meters across will pass within 1.2 lunar distances of Earth. The list of closest approaches in 2016 is quite exciting to look through The object 2016 QA2 discovered in 2016 in the nick of time, was about 70 meters across and came within 53,000 miles of Earth. Upon impact, it would have been an event similar to Chelyabinsk. Even larger, and far more troubling very close encounters have been predicted for the 325-meter asteroid Apophis in 2029, and the 1-kilometer asteroid 2001WN5 in 2028 and well within the man-made satellite cloud that surrounds Earth.

The first successful forecast of an impact event was made on 6 October 2008 when the asteroid 2008 TC3 was discovered. It was calculated that it would hit the Earth only 21 hours later. Luckily it had a diameter of only three meters and did not cause any damage. Since then, some stony remnants of the asteroid have been found. But this object could just as easily have been a 100-meter object exploding over New York City or London, with devastating consequences.

So in terms of planetary defense, asteroids are a dramatically important hazard we need to study. For some asteroids, we may have as little as a year to decide what to do. Although many mitigation strategies have been proposed, none have actually been tested! We need to test as many different orbit-changing strategies as we can before the asteroid with Earth’s name written on it is discovered.

Honestly, what more practical benefit can there be for a NASA mission than to materially protect Earth and our safety?

Check back here on Thursday, January 5 for the next installment!