October 31, 2015 | David F. Coppedge

Inventing Stars, Solar Systems and Universes

Always look into the methods used when scientists speak confidently about models for making things appear out of nowhere.

News from Comet 67P

Surprise discovery suggests ‘gentle’ start for Solar System (BBC News): “The discovery has come as a complete surprise to scientists who thought that oxygen would have reacted with other elements as planets were forming,” declares the normally overconfident BBC reporter Pallab Ghosh. “The results indicate that current ideas about how our Solar System formed may be wrong.”  See paper in Nature, “Abundant molecular oxygen in the coma of comet 67P/Churyumov–Gerasimenko.”

Modern Mystery: Ancient Comet Is Spewing Oxygen (Space.com): More about this “big surprise”:

What’s mystifying astronomers about the new find is why the oxygen wasn’t annihilated during the solar system’s formation. Molecular oxygen is extremely reactive with hydrogen, which was swirling in abundance as the sun and planets were created. Current solar system models suggest the molecular oxygen should have disappeared by the time 67P was created, about 4.6 billion years ago.

Discovery of molecular oxygen in comet tail forces us to rethink how the solar system formed (Christian Schroeder in The Conversation): Molecular oxygen has a ripple effect on models of the whole solar system: “That means that our solar system might have formed from an unusually warm cloud, which raises the question as to what might have caused this elevated temperature.” Other possibilities are bandied about. Schroeder puts a happy face on falsification: “We can look forward to the next surprises this comet has in store for us.”

Rosetta Mission: Ptolemy sniffs next piece of the comet puzzle (Science Daily): Ptolemy is one of the instruments on the spacecraft. It detected ice and CO2, but very little CO that was predicted. “Our results, from Comet 67P’s surface, has both surprised us as well as opened up a variety of new questions about how comets form and how they work.”

Rosetta scientists unveil the source of ice and dust jets on comet 67P (Monica Grady in The Conversation): The comet is darker than it’s supposed to be. The expectations were all wrong. “But despite this wealth of visual evidence for researchers there is a lot we still don’t know about the comet – including why it is covered in organic material rather than just ice and what causes its powerful jets of dust and ice.”

Planet Models

Now that we have seen that scientists can be surprised at how wrong their models are, let’s see some new models they’re promoting with hubris.

Growing the terrestrial planets from the gradual accumulation of submeter-sized objects (PNAS): Veteran planet-maker Hal Levison is at it again, cooking up planets out of dust. This paper is filled with assumptions, conveniently-chosen initial conditions, and leaps of faith, such as assuming dust grains will form pebbles without getting swept into the sun or blown out the disk. But it sure got nice coverage in the press.

Why Earth is so much bigger than Mars: Rocky planets formed from ‘pebbles’: New process explains massive differences between Earth and Mars
(Science Daily): Typical uncritical press coverage of the new Levison model. Gives the wizard the last word: “As far as I know, this is the first model to reproduce the structure of the solar system — Earth and Venus, a small Mars, a low-mass asteroid belt, two gas giants, two ice giants (Uranus and Neptune), and a pristine Kuiper Belt,” said Levison.”

Astrophysicists find Jupiter likely bumped giant planet from solar system (PhysOrg): Explaining the position of Uranus and Neptune requires a game of billiards with Jupiter and Saturn. Nobody saw a mythical fifth planet that was conjured up to get a new model to work. Conveniently, Jupiter ejected it without leaving a trace.

Star Models

‘One size fits all’ when it comes to unravelling how stars form (PhysOrg): Positivist coverage of interpretations of blurry images from a Chilean telescope. Article claims big stars form the same way as their models say small stars form.

Whoops, what about these?  Models are only simulations of reality. Reality is often more complex, e.g.: Astronomers find disk of young stars near center of Milky Way (Nature): “The discovery suggests there has been a constant supply of young stars to the galactic center, but where do they come from?” Daniel Clery asks. “The galactic center is thought to have used up its supply of gas from which to make stars long long ago, so astronomers will have to figure out some mechanism by which young stars are moved inward from farther out in the galaxy.” Aren’t there other possibilities? (1) Maybe they’re misclassifying young and old; or, (2) Maybe the galaxy isn’t as old as they think it is.

Astrophysics: Primordial stars brought to light (Nature): This optimistic article claims a possible success in the hunt for Population III stars, theoretical stars made out of pure hydrogen, with traces of helium and maybe lithium. That’s the only kind of star that could have formed after the big bang when those were the only elements.

Twinkle twinkle little star, I know exactly what you are;

For by spectroscopic ken, I know that you are hydrogen.

All the other elements had to form from supernovas, the story goes. Anyway, a certain galaxy seems to have “candidate” Population III stars, but they are mixed in with heavy-metal stars if that’s what they are. The observations appear to be model-dependent. “The authors find that the observations of CR7 are best explained by a hybrid stellar population containing both young, metal-free stars and an older, chemically evolved population, respectively emitting most of the UV and optical light,” reporter Bethan James writes.

Galaxy and Cosmology Models

Missing gravitational waves lead to black hole rethink (PhysOrg): Another upset reported. “Human understanding of galaxies and black holes is being called into question after an 11-year search for mysterious gravitational waves—famously predicted by Albert Einstein 100 years ago—failed to find anything.

New theory of stealth dark matter may explain universe’s missing mass (Science Daily): All of the above is only a model for 5% of reality, astronomers think. They’re still looking for the other 95%. Maybe it’s just “stealthy” like a ghost—a timely idea for Halloween.

Birth of universe modelled in one of largest cosmological simulations ever run (Science Daily): It’s not clear what the guys at Argonne National Labs are doing spending taxpayer dollars to run computer simulations on cosmology for the Department of Energy, but they have a zinger. They got stars and galaxies to form against their will out of a uniform fog after the big bang by mixing in copious amounts of lucky charms called dark matter. For those who would like to see an honest skepticism of these models, see Spike Psarris’s video, What You’re Not Being Told about Astronomy, Part II: Stars and Galaxies. He quotes leading astronomers who reveal that they don’t know what they are talking about. They have to invoke the Tooth Fairy twice (dark matter and dark energy), one embarrassed astronomer confesses. If stars and galaxies didn’t exist, they would be happy to explain why this is exactly what they expect, another says.

Science is the only career where you can be totally wrong and still keep your job and enjoy a great reputation in the media. The way you keep going is to look excited and glad about the fallen expectations, hyping the promise that the puzzle opens up new possibilities for better models. Now that you have seen the difference between hubristic models and reality, try your hand at interpreting these articles:

  • How we plan to bring dark matter to light (PhysOrg)
  • Dark matter universe (PNAS)
  • Have physicists seen the dying flash of dark matter? (Science)
  • X-ray signal from outer space points to dark matter (Science)
  • Our Universe: It’s the ‘Simplest’ Thing We Know (Live Science)
  • Evolution of the universe in unmatched precision (Science Daily): “New most comprehensive hydrodynamical simulation of the universe’s visible structure”
  • New precise particle measurement improves subatomic tool for probing mysteries of universe (PhysOrg)

Recommended reading: “The Scientific Method Is a Myth” by Daniel P. Thurs on Discover Magazine.

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Comments

  • John C says:

    Re: The Model Makers. This quote from the great Yogi Berra should keep them humble. “In theory there’s no difference between theory and practice. In practice there is.”

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