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Solar Systems Like Ours Are Likely To Be Rare
KentuckyFC writes "Astronomers have discovered some 250 planetary systems beyond our own, many of them with curious properties. In particular, our theories of planet formation are challenged by 'hot Jupiters,' gas giants that orbit close to their parent stars. Current thinking is that gas giants can only form far away from stars because gas and dust simply gets blown away from the inner regions. Now astronomers have used computer simulations of the way planetary systems form to understand what is going on (abstract). It looks as if gas giants often form a long way from stars and then migrate inwards. That has implications for us: a migrating gas giant sweeps away all in its path, including rocky planets in the habitable zone. And that means that solar systems like ours are likely to be rare."
Get Bruce Willis on the phone, time to go "Armageddon" on Jupiter's ass.
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I didn't RTFA, but I will when I get home.
But on the surface it seems more to me that they're just saying that solar systems have a life cycle that is marked by the location of gas giants. I don't really think that means that our setup is rare.
But if I am misinterpreting the blurb and that is what they're proposing I would still say we need to hold our horses on any real judgement. We've found these solar systems because our current method of seeking these solar systems out is going to be more likely to find this kind of activity as opposed to what we have here at home. I think we're jumping the gun a bit on this one. I say let them work it out for a couple of more decades and even then we should be a bit more cautious about such sweeping statements.
Dedicated Cthulhu Cultist since 4523 BC.
when they have capability of detecting Earth > Venus > Mars size planets
they don't have much data do they to base their theory on?
I thought it was commonly understood that for a solar system like ours to exist, that there needs to be a gas giant to act as a "protector" for the habitable planet(s). That is, the larger planet acts as a gravity well to lure some of the larger objects that could collide into the habitable planet. From the summary, it merely seems to be saying that the gas giant forms closer to the star than originally thought, but that it migrates outwards later in its life and helps to clear a zone for the habitable planet to exist.
"... Everything looks like a nail" situation to me. We've only really had the ability to discover LARGE planets around solar systems. Also, the shorter the orbit period, the easier it is to detect.
So logically, the planets we've found to date look NOTHING like those of our solar system. Jupiter's orbital period is 4332.71 days!!! And we are comparing that to the VAST majority of discovered planets(hot Jupiters) with orbital periods of less than 10 days?
Seems like this article belongs in the "Are US Voters Informed Enough About Science?" thread if you ask me.
Prof. Farnsworth - "Oh a lesson in not changing history from Mr I'm-My-Own-Grandpa!"
Even if solar systems configured like ours are rare, it doesn't suggest that is a problem for either the development of life or intelligence as we'd recognize it (and really is no problem for any other forms of "life").
A gas giant in the "habitable" zone may have multiple moons that end up habitable. If Jupiter was in Earth's orbit its entirely possible 2-3 or more of its moons would be habitable in some form.
That both increases the odds by having more places habitable, but increases the possibility of panspermia, so you could actually have greater diversity in that situation.
Nothing says "sanity" like a preemptive defense.
Are you suggesting that Jupiters migrate?
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Incoming!
The interesting data is not how many hot Jupiters are found, but how many stars do not have hot Jupiters.
Here's a list of extrasolar planets (last updated in January); and another list. Note the large number of stars that have planets found with mass less than Mj. The converse of that is that those stars do not have planets of mass greater than Mj. The problem, of course, is that negative results are much less published than positive results. However, here is a list of three published papers that listed stars with no planets found (that is, no planets large enough to detect-- which is to say, no hot Jupiters. This list is somewhat out of date, as of 2006.)
So the story is a little incomplete. Some solar systems have hot Jupiters, which in their migration inward disrupt smaller, earthlink planets... but by no means all.
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Outsider theories always have the burden of proof on their own shoulders. To paraphrase someone famous, "there are many questions fools can ask that wise men struggle to answer." There's no where this applies more than in science. Creation Science can throw out some sticky questions and make some points that are hard to disprove.
But Science is about proving things, not suggesting every possible idea and disproving them one by one. For a well established idea that has made a lot of successful predictions, even a known incomplete idea like the standard cosmological model, to be tossed aside, there needs to be an overwhelming amount of evidence, not just some compelling questions.
If an alternative model of the universe explains the preponderance of evidence we already have (such as the background radiation, the count of galaxies, the scarcity of structures above a certain scale, the calculated mass of galaxies, the total amount of gamma radiation etc.) as well as a current theory, as well as making successful new predictions that existing models failed to make, then over a process of several years, people in the field would become convinced, and as the literature is peer reviewed, the dogma would shift. But established scientific ideas are SUPPOSED to be dogma. It isn't politics. Equal time isn't given to competing ideas, that's not the way it works. There are too many bad scientists and professional crackpots, the system would collapse without a hierarchy of opinion.
And all science works this way and always has. Even the sciences that cure disease and deliver technological miracles. Since those things keep happening, I'm confident as a semi lay person that science, while certainly getting many small details wrong and making mistakes and sometimes taking too long to come to the right conclusions, is still heading in a monotonically positive direction.
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Yes, our theories were WAY off. No one predicted that these hot Jupiters were out there. Now they make up almost all of the planets we've detected to date. The point I was trying to make is that we can't detect solar systems like ours yet. Unless MAYBE it was in the alpha centaurus system and then MAYBE if it's Jupiter equivalent were to pass in front of one of the stars.
Please, tell me how many exosolar planets we've found with orbital periods greater than 365 days? How about 4000+ days like Jupiter?
Talking about how rare we are, without even another example, because we lack the ability, is just another theory that will fall - kinda like the planet formation theories that lacked the ability to predict "hot Jupiters". Now they have gone to the other extreme and theorized that EVERY solar system starts out with hot Jupiters. You know, because that is all we can presently detect.
How is that irrelevant? It's EXACTLY the "To a hammer, all looks like a nail" analogy I started with. Since that is all we have the ability to find at present, now all solar systems must start out that way?!?!?!?
This is the same mistake all the theorists made to start with, since all we had was our own solar system to base this upon. Now they have gone exactly the opposite way in their theories which is repeating the same mistake they initially made.
Yes, you adapt your theories based upon more and more observational data. But when you KNOW your observational data is limited to one subset of possible outcomes(which makes our own solar system damn near impossible to form) and you claim "victory", that's just very illogical to me.
Prof. Farnsworth - "Oh a lesson in not changing history from Mr I'm-My-Own-Grandpa!"
But Science is about proving things, not suggesting every possible idea and disproving them one by one.
Where on Earth did you get that idea? One of the first things you learn about science is that it doesn't prove anything, only disprove. The scientific method is a three step process:
You observe phenomenon, create a theory that explains it and makes some predictions and then test these predictions. If the observations don't match the predictions you either discard or refine the theory. If they do, then you keep it around until you find some new observations that don't match up with the predictions.
The reason creationism is not science is that it makes no testable predictions. Whether it is true or not can not be tested and so is an irrelevant question to science.
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The most important thing that you need to understand is that the large number of "hot jupiters" that have been found have essentially disproven existing theories of solar system formation. This is not a case where a new theory is proposed to replace an existing theory that already explains most of the evidence ala Einsteinian physics replacing Newtonian physics. This is a case where we have essentially no theory at all that explains the observed evidence.
The cake is a pie
Personally I think it's hard to decide if our planetary system is rare or not just by computer simulations. There are too many factors involved to make it easy to calculate how a planetary system evolves.
There have been many guesses over the last century about how the planets did form. But from the data we now have from a few other planetary systems we can at least say that a few of them have large planets (gas or not remains to be seen).
And what would say that a planet has to be the size of earth to provide for life? A gas giant may be good for life too, but maybe not the life we know here.
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You and colmore are both right. Colmore beautifuly summarized how science actually operates. Your observations reflect understandings gleaned from the philosophy of science, in particular Karl Popper's falsifiability criteria. Popper developed this idea to show how one can delineate science from pseudo-science. It is a valuable philosophical insight and is useful as a criteria of demarcation between science and unscientific ideas. But, it is not a good foundation for understanding the actual methodologies used by science. Actual science proceeds based on some assumptions such as the uniformity of natural causes that cannot be proven, but which underlay belief in the validity of probabilistic induction and the idea that science illuminates "truth" in some sense and gives us greater knowledge of reality.
As a working scientist: no he (colmore) didn't. Although his intentions were good.
In science you make some assumptions when creating your theory, but if you find evidence that indicates those assumptions are likely false then it's time to make a new theory. That INCLUDES such assumptions as the universe being consistent.
An excellent example of just that idea is quantum mechanics. The universe, it seems, isn't consistent in quite the way that classical physics thought it was: a cause doesn't always produce the same effect. When we discovered this, we designed quantum mechanics to take this aspect into account.
Both you and colmore use the word "prove." Science is not about proving things, and of course you cannot prove assumptions, or anything else, for that matter. In science there is no proof, because there is always the possibility that you will find a counterexample.