Start Over: The Evolution of Planets Is All Wrong
Ideas about planetary evolution are so far off base with observations of exoplanets, it’s time to wipe the slate clean.
“Planets in Chaos,” Ann Finkbeiner titles an article in Nature. Actually, the planets are doing just fine, but the theories to explain their origins are so far off, they are not salvageable. The subtitle reads,
The discovery of thousands of star systems wildly different from our own has demolished ideas about how planets form. Astronomers are searching for a whole new theory.
Her review brings to mind Huxley’s quip that many a beautiful theory was destroyed by an ugly fact. “Not so long ago — as recently as the mid-1990s, in fact — there was a theory so beautiful that astronomers thought it simply had to be true.” It was the core accretion theory (the updated Laplace Nebular Hypothesis). It was beautiful because it fit well with Darwinism’s slow, gradual accumulation of infinitesimal changes. It was beautiful, too, because it explained our solar system’s arrangement: rocky planets near the sun, icy bodies farther out. “And because the same principles of physics and astronomy must apply throughout the Universe, it predicted that any system of ‘exoplanets’ around another star would look pretty much the same.” See? It even made predictions. Good theory.
Reality had a way of punishing scientists for extrapolating from a sample of one.
But in the mid-1990s, astronomers actually started finding those exoplanets — and they looked nothing like those in our Solar System. Gas giants the size of Jupiter whipped around their stars in tiny orbits, where core accretion said gas giants were impossible. Other exoplanets traced out wildly elliptical orbits. Some looped around their stars’ poles. Planetary systems, it seemed, could take any shape that did not violate the laws of physics.
The sad conflagration of the beautiful theory has been told and retold before (3/21/06, 5/21/09, 8/31/10), especially since the Kepler spacecraft turned up the heat. What’s new for July 2014 is that astronomers have still made no progress with alternative theories.
The findings have triggered controversy and confusion, as astronomers struggle to work out what the old theory was missing. They are trying ideas, but are still far from sure how the pieces fit together. The field in its current state “doesn’t make much sense”, says Norm Murray of the Canadian Institute for Theoretical Astrophysics in Toronto. “It’s impossible right now to account for everything,” agrees Kevin Schlaufman, an astrophysicist at the Massachusetts Institute of Technology (MIT) in Cambridge. Until researchers reach a new consensus, they will not be able to understand how our own Solar System fits into the grand scheme of things, let alone predict what else might exist.
It’s not like Nature to leave a tragedy hopeless, so Finkbeiner does offer some glimmers of hope. New concepts of interaction and migration are helping to explain how some planets went wildly eccentric, or how hot Jupiters got so close to their stars, for instance. Many astronomers still believe “core accretion has some things right,” such as the idea that planets are leftover products of the origin of stars. Strangely, she tells the old theory as if it is still true, after having falsified it in the introduction.
But then she gets into the era of 2001, the Space Oddities. “It was like, ‘What! We weren’t even looking for that” one astronomer said at the 1995 announcement of the first hot Jupiter. The catalog of unpredicted anomalies has left astronomers scratching their heads. In accordance with Bloch’s Law, “Every solution breeds new problems,” the proferred solutions did just that:
To explain hot Jupiters, for example, they suggest that the planets did not stick around at their birth place in the cold outer reaches of stellar disks. Instead, the infant giants spiralled inwards as viscous gas in the disk slowed their orbits. At some point, for reasons unknown, they stopped their death spirals and settled into stable orbits close to their stars. Despite the extreme temperatures, the giant planets had strong-enough gravity to keep hold of their gas.
Super-Earths also don’t fit the old “beautiful” theory, she adds; they are even “harder to account for.” But does a pithy analogy help? “Super-Earths are probably not nice, stereotypical birds,” says Eric Ford, an astrophysicist at the Pennsylvania State University in University Park. “Maybe some are more like penguins.” Humor can be a distraction on work time. “The sheer size of the super-Earth flock requires explanation,” she reminds the workers, like a stern boss. “The standard theory cannot do that because in existing models, the central regions of stellar disks contain much too little material to create several close-in super-Earths.”
The workers went to work, adding heavier disks, and “migration, migration, migration.” That process seems to be the new dark matter to explain planet-makers’ anomalies. Unfortunately, migration models have their own problems that challenge migration as a scientific theory:
Such models are appealing, but the concept of migration, especially of the smaller planets, gives some researchers pause — if only because no one has ever seen it happening. The necessary observations may not be possible: stars young enough to have planets migrating through protoplanetary disks are still surrounded by dust, and their light flickers, making it extremely unlikely that current methods will be able to pick out the dimming caused by a transiting planet. The theory is not settled, either. Modellers have found it hard to explain why migrating planets, big or small, would stop in the orbits that astronomers have observed. In simulations, says Winn, they don’t: “the planets plop right down on the star”.
If planets migrate as quickly as models predict, moreover, they should mostly be gone by now, melted to oblivion inside their parent stars. Astronomers should not be oblivious to oblivion. The “biggest question” still hounds them: “why our Solar System is so different.” Our neat arrangement of planets in stable orbits, with a lively planet safe in its habitable zone, doesn’t look anything like the majority of extrasolar planetary systems. Breaking News: One of the most Earthlike planets ever found turns out to be an illusion, New Scientist and National Geographic reported. The “planets” were probably just starspots due to the star’s magnetic field. Farewell, Gliese 581 d. Jacob Aron quipped on New Scientist:
Type the name “Gliese 581 d” into a search engine, and you’ll find hundreds of tantalising images of an Earth-like world. The exoplanet has been a top contender for the most life-friendly world beyond our solar system since it was discovered in 2007. There’s just one problem – it probably doesn’t exist.
Current status for planet formation theories: bad news.
Meanwhile, researchers continue to nurture their mess of models, which have grown almost as exotic and plentiful as the planets they seek to explain. And if the current theories are disjointed, ad hoc and no longer beautiful, that is often how science proceeds, notes Murray. “Life,” he says, “is like that.”
Finkbeiner’s happy ending to the story lies in the future. “Future observations may give some answers,” she dreams.
Try that excuse at home or at work. Susie, you’re room is a mess. I’m nurturing the mess; life is like that. John, your report did not follow my instructions. It’s exotic; life is like that. Mechanic, you put the parts in the wrong places. It’s disjointed, but life is like that. Lawyer, you’re just making stuff up. It’s ad hoc, but life is like that. Home decorator, you ruined my living room. It’s no longer beautiful, but life is like that. Son, why did you get an “F” on your paper? I got some things right. Bookkeeper, what are these strange entries you put in the ledger? This requires explanation! They’re not your stereotypical birds; maybe some are like penguins. Scientist, everything you said is wrong. Future observations may give some answers.
Neil Tyson, what are you going to say about this article? Where is your positivism now?
This article is all the more aggravating when you remember that secular cosmogonists have sold a false scenario for centuries since Laplace, propounded non-stop for decades by artwork, textbooks and TV documentaries that have used this debunked theory to prop up a molecules-to-man scenario, supposedly illustrating why science is superior to religion. We’ll take Genesis 1:1 any day over this falsified Nebulous Hypothesis.
They’ve had their chance. Give the materialistic storytellers the boot. Earth is a privileged planet (5/24/11) in a designed solar system; that is where the evidence leads. Extrasolar planets can be explained as the end products of destructive processes, not creative processes. Design is evident everywhere; like our own creation, we hold these truths to be self-evident among rational beings on God’s green Earth.