Planets May Form in Hundreds, Not Millions, of Years

Seanasy writes "Recent simulations on the Pittsburgh Supercomputing Center's Terascale Computing System suggest that planet formation may take a lot less time than previously thought. The results were published in SCIENCE."

Comments

Correction: gas giants & abstract

[MacAndrew]

The study actually looked at gas giants like Jupiter and Saturn. My understanding is that these planets formed by scooping up gas as they orbited the sun. The interior rocky planets of the inner disk probably took longer to achieve final shape, though their materials would have been the first to cool into solid form.

Neat stuff.

Here's the Science abstract:

A Quickie Birth for Jupiters and Saturns
Richard A. Kerr

On page 1756, a group of astrophysicists presents computer simulations of the nascent solar system that suggest a possible mechanism for the formation of the gas giant planets: runaway fluctuations in the density of the protoplanetary disk. In their model, gas giants of about the right size, number, and orbit condense from a disk of gas to look like very young Jupiters. The trick was to simulate the process in fine detail so that the gas's own gravity could take over.

Full Text

More abstract

[MacAndrew]

Odd, they have a different abstract from the summary. Sorry, I don't have a full subscription to Science.... not that I would blow their copyright and post it here. :)

To wit:

Formation of Giant Planets by Fragmentation of Protoplanetary Disks

Lucio Mayer,1*dagger Thomas Quinn,1* James Wadsley,2 Joachim Stadel3dagger

The evolution of gravitationally unstable protoplanetary gaseous disks has been studied with the use of three-dimensional smoothed particle hydrodynamics simulations with unprecedented resolution. We have considered disks with initial masses and temperature profiles consistent with those inferred for the protosolar nebula and for other protoplanetary disks. We show that long-lasting, self-gravitating protoplanets arise after a few disk orbital periods if cooling is efficient enough to maintain the temperature close to 50 K. The resulting bodies have masses and orbital eccentricities similar to those of detected extrasolar planets.

1 Department of Astronomy, University of Washington, Seattle, WA 98195, USA.
2 Department of Physics & Astronomy, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4M1, Canada.
3 University of Victoria, Department of Physics and Astronomy, 3800 Finnerty Road, Elliot Building, Victoria, BC V8W 3PG, Canada.
* To whom correspondence should be addressed. E-mail: lucio@physik.unizh.ch, trq@astro.washington.edu

dagger Present address: Institute of Theoretical Physics, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.

PSC

[Hadean]

Here's a direct link to PSC's article, which does -not- require registration (bah).

As mentioned by another post, we're talking about "Jupiter-like" gas giants, not Earths. The reason it can't take millions of years: "The problem with [the current model], however, is that if the formation process takes too long, nearby stars will, in effect, boil off the gas envelope."

Re:PSC

[Hadean]

Oops, for some reason I didn't realize there already was a direct link... Ah well, here's a copy of it in case it gets Slashdotted (gotta have a real reason to reply, right?):

"Planets May Form Faster than Scientists Thought"

Simulations at Pittsburgh Supercomputing Center show that planets can form in hundreds of years.

PITTSBURGH, December 11, 2002 -- Taking advantage of the computing capability of LeMieux, the Pittsburgh Supercomputing Center's terascale system, scientists have determined that large, Jupiter-like planets -- similar to those observed outside Earth's solar system -- can form in dramatically shorter periods of time than previously thought.

The findings, published in SCIENCE (Nov. 29), challenge accepted thinking that it takes millions of years for such planets to form from the pancake-shaped nebula of gas and dust swirling around young stars.

"We used a new model of planet formation," said University of Washington astrophysicist Thomas Quinn, who led the research team, "that couldn't adequately be tested without this kind of computing power, and we found that these giant planets can form in hundreds of years, rather than the millions that the standard model predicts."

Using LeMieux, the most powerful system in the United States committed to public research, the researchers carried out a series of planet formation simulations. Because of LeMieux, the researchers were able to include roughly ten times more detail than previous similar work, and this increased resolution led directly to the new findings.

Nearly 100 extrasolar planets have been detected within the past decade, with masses that range from roughly the size of Jupiter to ten times larger. These discoveries prompted thinking about how large planets, similar to Jupiter and Saturn, form. Called gas giant planets, these planets have most of their mass in a gaseous envelope that surrounds the solid core.

The standard model holds that a core of solid matter congeals from the swirling disk -- called a protoplanetary disk -- around young stars, a process thought to take a million years or so, with another million to ten million years to accumulate the gaseous envelope. The problem with this model, however, is that if the formation process takes too long, nearby stars will, in effect, boil off the gas envelope. "If a gas giant planet can't form quickly," said Quinn, "it probably won't form at all."

An alternative model holds that giant planets form directly from instabilities in the protoplanetary gas, without the need for a solid-matter core. Until the recent simulations, this model hadn't produced convincing results. "The main criticism," said Quinn, "was that this model wasn't ready. Nobody was making predictions with it. But that's because they didn't have enough computational horsepower."

The recent simulations -- using 30,000 processor hours on LeMieux -- produced a distribution of masses and orbits comparable to observed extrasolar planets. According to the astronomical findings since the mid-1990s, these gas giant planets appear to be fairly common. "If these planets can't form quickly," says Quinn, "they should be a relatively rare phenomenon, and if they form according to this mechanism they should be relatively common."

Authors of the research, besides Quinn, are Lucio Mayer, a former University of Washington post-doctoral researcher who recently joined the University of Zurich, James Wadsley of McMaster University, Ontario, Canada and Joachim Stadel at the University of Victoria, British Columbia, Canada.

Established with an August 2000 grant from the National Science Foundation, LeMieux comprises over 3,000 Compaq Alpha EV68 processors, providing over six teraflops (six trillion calculations a second) of computational capability to U.S. engineers and scientists.

The Pittsburgh Supercomputing Center is a joint effort of Carnegie Mellon University and the University of Pittsburgh together with the Westinghouse Electric Company. It was established in 1986 and is supported by several federal agencies, the Commonwealth of Pennsylvania and private industry.

Re:This isn't at all surprising

[MacAndrew]

This is a troll, right?

God made the Earth about 6000 years ago so it couldn't have formed in millions of years.

Interesting logic. In other words, "Because CONCLUSION, then QUESTION must lead to CONCLUSION." I believe this is called a syllogism.

I don't care if oil forms in ten minutes, the Earth is not 6,000 years old to a 99.9% level of certainty unless God has a very odd sense of humor (possible). Personally I'm leaning towards 4.5 billion years.

Seriously, in defense of Christianity, and I am agnostic, scant few Christians subscribe to creationism or intelligent design, so whatever you may believe be careful not to stereotype Christians based on it.

Re:30,000 processor hours

[Seanasy]

Seti@Home couldn't handle this type of problem. This is parallel processing -- where nodes work on different parts of the problem at the same time. The catch is that the work done by each node affects other nodes so that super-fast connections between nodes is a must. Otherwise, nodes sit idle waiting for data. Doing this in a disributed manner on the Internet isn't even feasible.

Re:Geez!

[Teancom]

And in a desperate attempt to correllate this poster's comment with the story that it is attached to:

"I have not checked out those reviews, but they must have been written very quickly!"

Crap, that's not funny to me either :-(

Oh, well, I guess there is no way to make the previous poster's comment make sense in this context. Say lah vee!

Velikovsky (and James P. Hogan) would be pleased!

[TrebleJunkie]

Wow. And to think that Velikovsky was just about run out of the scientific community 50 years ago for putting forth a similar idea, among others -- that planets could form rather quickly, in years or hundreds of years, rather than the millions of years previously thought.

This is also sort of the subject of James P. Hogan's novel, Cradle of Saturn. If you've never read James P. Hogan, you should. Good, good stuff.

Re:This isn't at all surprising

[MacAndrew]

Unremarkably, you miss that the study suggests the gas giants formed quickly not recently.

6,000 years is a lot more reasonable-sounding ... why? A staggering amount of evidence point towards a time period much, much longer. "Reasonable" is believing things in reasonable accord with the evidence, and the estimate need never be completely proved to be accepted as fact. That's just not how people do things in real life.

Evolution, for that matter, is a fact under the same principle of overwhelming evidence. The debate or theory now centers on how it happened, which might be Darwin's theory or something else; if Darwin is disproved the fact of evolution will remain. You are free to believe otherwise, but won't change the real world any more than your refusal to believe in the fact of gravity will enable you to fly.

Is this disrespectful? Yes. I think it would be untenable to grant any belief a held by any person person with equal weight. I thought creationism, with its tenuous basis in the Bible, had been left by the wayside long ago, though I realize there will always be a core that will believe anything.

Re:This isn't at all surprising

[MacAndrew]

I wouldn't presume anything; as a scientific type I am obsessed with fact.

I'm not sure whether you think the % of creationists is high or low, and I don't have time to research the web. There are however various surveys out there; the question has been studied extensively because of the evolution v. creationism debate for public school classrooms.

I should add that by Creationist I intend the fundamentalists who insist on a literal interpretation of Bible (if such a thing is possible given its complexities, various translations, and internal contradictions -- this is not a criticism but an acknowledgement I hope most of us can make) that leads to the 6,000-year figure and so on. These are the most conservatives.

As with most things, Americans cover the spectrum from Creationist to evolutionary-ist (?) with most kind trying to be accommodating. I don't count these accommodating Christians among the ones who claim their reading of the Bible is the end of all debate, and so the % who think maybe creationism should be discussed in school are not the hard-liners most folks think of when they hear "creationist." I personally think many of those who vote for creationism never had evolution properly explained to them -- note the correlation with less education. A poll may thus unfairly suggest their minds are closed to alternatives, as with the creationists. Better PR for evolution is part of why we've seen an upsurge of "intelligent design," a kind of soft-sell creationism.

Sure, but...

[Myco]

It takes much longer to get the fjords just right.

but...

[Transcendent]

Where do you draw the line as when the process begins/ends?

You have a large number of events that need to be carried out before the actuall planet sphere begins to form...

1) Matter needs to be created

2) A vast ammount of gas needs to slowly collect together.

3) A stable center of gravity needs to be distinguished

4) That gravity needs to slowly (and exponentially) gather more mass around it to finally form the planet.

But when do you start the stop-watch? Step 1... or 4?

It's like saying "I can put together a ham sandwich in 30 seconds!" ...but how long did it take for all the parts to form like raising the pig or growing the wheat?

If you go back far enough, it took billions of years for that sandwich to be created... since the beginning of time...

Understanding the "hot Jupiters"

[Drog]

For anyone interested in more details, this story appeared here a week ago. An interesting comment pointed out that this theory has major implications in understanding the hundred or so "hot Jupiters" that have been found around other stars. Most have orbital periods of only a few days and orbit their star at a distance less than Mercury's. This new theory may suggest that hot Jupiters are actually newly-formed gas planets and perhaps even a transient phenomena.

Re:This isn't at all surprising

[dvdeug]

The earth couldn't be millions of years old because God created it about 6000 years ago. If the creation of the earth about 6000 years ago is accepted as truth, then we use this to eliminate the question of the age of the earth being 4.5 billion of year old.

If we start with the assumption that the world is 6000 years old, then given that assumption, it's 6000 years old. If you start without any assumption of Christianity's truth, it looks like the world is roughly 5 billion years old. If you start by assuming the Bible is true, and the information of our senses is true, then you have a fairly complex question, with different answers depending on the believer.

it is impossible to be a true Christian and not believe that God created the world.

No where in the Bible does it say the world was created 6000 years ago. I think the Bible has pretty good evidence that the Hebrews didn't view large numbers with the precision we did - notice the symbolic use of 70, 70 times 70, and 144,000 at various places in the bible. It would have been very hard to explain to them that the world was five billion years old. Christians* believe God created the world; but they don't necessarily believe that he felt compelled to give the exact blow by blow to the Hebrews, instead of giving them some version they could understand.

* Well, most Christians, at least.

About that syllogism...

[MacAndrew]

I'll try to wrap up one tiny detail....

The syllogism and its little brother the enthymeme date back to ancient Greece and are styles of argument. The reason the syllogism gets criticized to the point of being deprecatory is that it is easily abused.

Here:

Major premise: The universe is older than 6,000 years if some of its components took longer than 6,000 years to form.

Minor premise: The gas giants took less than 6,000 years to form.

Conclusion: The universe probably (more so than yesterday) took less than 6,000 years to form.

To me, there are several logical flaws there, and this has not a thing to do with religion. The main one is that the major premise is false; the theories concerning the age of the universe are not based on the sum of series of events. You may be making this false assumption because (to my understanding) the 6,000-year version of creationism is derived from how long various individuals lived, added to their descendants, and so on.

So the gas giants might never have formed, the estimates for the age of the universe would not change because they are indifferent to gas giants. Really, the formation of the planets is a bit trivia in the view of the universe, and the difference in formation time proposed here, mere millions of years, are the 0.01% insignificant blink of an eye to a universe thought to be over 10 thousand million (billion) years of age, and a solar system of a sprightly 4.5 billion (again with a "b").

Another trivial bit of semantics is that you misuse the word "hypothesis." Science really doesn't use hypothesis in this way, and when scientists speak of theories they don't mean educated guess, but a framework to explain a fact. So the age of the universe is a fact to a very high degree of certainty; it is older than 6,000 years by billions; and various theories strive to explain the nature of or refine the fact. But whether a theory of good or bad does not alter the fact, and the age of the universe is something so well established that it is inconceivable it will someday turn out to be 6,000 years. Besides the huge difference between the estimates, there's enough evidence on earth -- even the weathering of a mountain takes millions of years -- the pyramids haven't weathered much in that time -- and I won't even bring up the fossil record.

But again, even if these events happened faster than we can imagine, the age of the universe is judged by independent data.

The only remaining hope for a doctrinaire 6,000-year view would be that the universe and earth were created pre-aged, but I doubt the Bible supports that view. I don't care how many people believe it, the majority has erred often enough before, is the name of many causes. You acknowledge that truth isn't determined democratically anyway -- then turn around and say "I am being persecuted for what are mainstream beliefs in much of the US." No, you are being criticized (persecuted? that's a little much) not for relating "popular" beliefs but for your faulty logic concerning astrophysics, and science generally. Don't take refuge in "mainstream." And I am not claiming that God lies, just that falliable humans don't get the message right sometimes.

I would think it obvious that the Bible makes heavy use of metaphor, and that things like the 6 days of creation may not be at all literal. Of course I'm not the first to wonder about this. But I think more and more people will eventually accept that the Earth is old and move on to that evolution debate, or something else. The truth of the Bible is hardly imperiled.

Re:About that syllogism...

[young-earth]

Your post is wonderful at describing and detailing the logic and flow of argument. Thanks for providing that clear explanation for those who are challenged in that arena.

None of us were around when the earth was formed, whether it be supernaturally or by an accretion disk or some other method. Therefore we must either infer or deduce to arrive at a belief of what happened. Since no reproducible experiment can absolutely tell us what happened in the past, there is no hard empirical proof. So we must make assumptions in order to arrive at a belief system, whether it be Biblical or the current scientific beliefs (and there are more than one of those).

One of the key assumptions for me as a creationist is that God does not lie, and if He says He made the universe in six days, then we (at least I) take Him at His word. A key assumption for most astrophysicists and astronomers is that the rate of radioactive decay is constant, that the earth was never inside the event horizon of a white hole, and that things are now as they have always been. In other words, that conditions are constant and that therefore tests made today will work the same tomorrow.

Did you notice that bit I threw in there about inside the event horizon of a white hole? If that did occur, it is absolutely possible for the earth to be formed in days while billions of years passed in the stars, due to time effects at the event horizon. This allows starlight to travel at current light speed to the earth and be visible even though the earth is relatively young. This "white hole cosmology" is a brilliant work by Dr. Russ Humphreys, a Ph.D. physicist at Sandia National labs. If you're interested shoot me an email and I'll send you more info.

Re:About that syllogism...

[MacAndrew]

I appreciate the sincerity of your views. You may also be right.

What I have disliked about creationism is its claim to being scientific when it has but one view of the possible truth, and only looks for evidence to support that presupposed truth. Unlike proposing a theory, the investigator asserts that if experimentation does not prove the assumption, then the experiment is flawed. This is closed-mindedness incompatible with science.

By contrast, "white holes" and whatever else might support creationism, would be part of the scientific discourse. This is far better than the argument that the mere possibility of a flaw in a theory means that all views are of equal value. It is really a question of probabilities, and the current estimates of the age of the earth, using different approaches, and considered to be very, very probable.

The strictly hypothetical white holes -- proposed but unproven to even the satisfaction of their proponents -- will of course require theory or evidence. Most all of the arguments I have heard for 6,000-year creationism (the "young earth" subset) amount to negative "You don't know for sure" or "There seems to be an inconsistency here" rather than positive proof of a mechanism for such a radical alternative model. I'm not saying it can't be done, I'm saying it hasn't been done, and the faith of its proponents, however sincere, can not carry weight with the rest of us.

As someone who has spent much of his life reading, I also find untenable the view that there is one literal view of the Bible. I don't see, for example, any way of proving that the "six days" was six literal days (notice "literal day" means something quite different from "literal reading" -- does this mean there is no literal meaning of literal?) as we know them, and not a part of the metaphors and poetry so prevalent in the Bible. Indeed, I challenge anyone to prove that only one interpretation of any text is possible (if I tell you to "stop," do I mean stop what you are doing? to stop talking? to stop what someone else is doing? to hand me something to hold the door open? or hand me a part for my flute?). Maybe some readings are more faithful than others, but one sole literal one? There is a big gap between stating such an interpretation and proving it. The label "literal" is to me an attempt to squelch debate, like claiming to be a patriot in a political debate.

Dr. Humphreys presents an example of the indeterminacy of literalism. If you look closely at what he's saying, he is trying very hard to extract the "right" interpretation of individual words in the rather terse Genesis story that might comport with theories or future theories of physics. This is all the more tricky because the original words were not in English, are quite ancient, and lack precise translation. So he is interpreting, as he must -- but game over for literalism. Maybe he has it backwards and should determine what the words mean by looking to the natural phenomena that the words describe rather than insisting the "six days" is precise and the rest merely needs to be interpreted to suit it. Why are some words literal and others not?

If Dr. Humphreys can pull it off and dethrone the most brilliant physicists of the last hundred years, more power to him. It will be an enormous contribution to mankind, and a boon to "young earth" creationists. But it is much much much too soon to declare such a revolution.

I am not trying to answer any of these questions, and I am not addressing the infalliability or existence of God; rather harping on the oft-proven falliability of humans to get the message right. I'll bet even creationists misunderstand or disagree with one another from time to time, or there wouldn't be so much discussion among them of what Genesis means. And how has the understanding of Bible changed in the past, and how will it change in the future? If falliability infects science, why does it not infect the "literal" reading of the Bible? Humans are flawed and have imperfect knowledge, so any scientist who tells you science can not be wrong -- not ever -- is lying or deluded. Any creationist who says the same...?

But in any event -- I do appreciate your effort to approach the question thoughtfully. Keep an open mind, I'll do the same.