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Planet-Formation Model Indicates Earthlike Planets Might Be Common
On 10 Dec 2003 17:37:01 GMT, (Ron Baalke)
wrote: "Our simulations show a tremendous variety of planets. You can have planets that are half the size of Earth and are very dry, like Mars, or you can have planets like Earth, or you can have planets three times bigger than Earth, with perhaps 10 times more water," said Sean Raymond, a University of Washington doctoral student in astronomy. Solid planets three times Earth's diameter? i.e. with more than 27 times the mass? (Presumably considerably more than 27 times, since the core would be pretty compressed at that stage.) Is that really possible? -- "Sore wa himitsu desu." To reply by email, remove the small snack from address. http://www.esatclear.ie/~rwallace |
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Planet-Formation Model Indicates Earthlike Planets Might Be Common
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Planet-Formation Model Indicates Earthlike Planets Might Be Common
In article ,
Russell Wallace wrote: On 10 Dec 2003 17:37:01 GMT, (Ron Baalke) wrote: "Our simulations show a tremendous variety of planets. You can have planets that are half the size of Earth and are very dry, like Mars, or you can have planets like Earth, or you can have planets three times bigger than Earth, with perhaps 10 times more water," said Sean Raymond, a University of Washington doctoral student in astronomy. Solid planets three times Earth's diameter? i.e. with more than 27 times the mass? (Presumably considerably more than 27 times, since the core would be pretty compressed at that stage.) Is that really possible? If the density is the same, gravity, which is proportional to radius times density, would be three times as great. On the other hand, if it is three times as massive with the same density, the gravity would be less than 1.45 as great. -- This address is for information only. I do not claim that these views are those of the Statistics Department or of Purdue University. Herman Rubin, Department of Statistics, Purdue University Phone: (765)494-6054 FAX: (765)494-0558 |
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Planet-Formation Model Indicates Earthlike Planets Might Be Common
"Russell Wallace" wrote in message ... On 10 Dec 2003 17:37:01 GMT, (Ron Baalke) wrote: "Our simulations show a tremendous variety of planets. You can have planets that are half the size of Earth and are very dry, like Mars, or you can have planets like Earth, or you can have planets three times bigger than Earth, with perhaps 10 times more water," said Sean Raymond, a University of Washington doctoral student in astronomy. Solid planets three times Earth's diameter? i.e. with more than 27 times the mass? (Presumably considerably more than 27 times, since the core would be pretty compressed at that stage.) Is that really possible? Where did you see the word diameter in the above quote. Perhaps bigger in this context referred to volume or mass. |
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Planet-Formation Model Indicates Earthlike Planets Might BeCommon
On Fri, 12 Dec 2003, Russell Wallace wrote:
|Solid planets three times Earth's diameter? i.e. with more than 27 |times the mass? (Presumably considerably more than 27 times, since the |core would be pretty compressed at that stage.) Is that really |possible? They probably wouldn't rotate as fast, would they? |
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Planet-Formation Model Indicates Earthlike Planets Might Be Common
On 13 Dec 2003 11:37:07 -0500, (Herman Rubin)
wrote: In article , Russell Wallace wrote: On 10 Dec 2003 17:37:01 GMT, (Ron Baalke) wrote: Solid planets three times Earth's diameter? i.e. with more than 27 times the mass? (Presumably considerably more than 27 times, since the core would be pretty compressed at that stage.) Is that really possible? If the density is the same, gravity, which is proportional to radius times density, would be three times as great. *nods* 3G would be survivable to life forms adapted for it, of course - but the problem I'm thinking of isn't the surface gravity, it's the availability of 27 Earth masses of solid material? -- "Sore wa himitsu desu." To reply by email, remove the small snack from address. http://www.esatclear.ie/~rwallace |
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Planet-Formation Model Indicates Earthlike Planets Might Be Common
On 13 Dec 2003 05:20:15 -0800, (Mike Miller) wrote:
(Russell Wallace) wrote in message ... Solid planets three times Earth's diameter? i.e. with more than 27 times the mass? (Presumably considerably more than 27 times, since the core would be pretty compressed at that stage.) Not all solid planets are as dense as Earth. Luna and Mars are about 60-70% Earth's density. You'd still be talking ~20 Earth masses, before taking compression into account... And those solids - silicates and metals - do not compress much (unlike hydrogen in its many forms), so the diameter will be about 3x higher. And silicates and metals do compress significantly at the pressure encountered in Earth's core; that's why Earth is denser than Mercury, despite having a lower percentage of metals. -- "Sore wa himitsu desu." To reply by email, remove the small snack from address. http://www.esatclear.ie/~rwallace |
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Planet-Formation Model Indicates Earthlike Planets Might Be Common
On Sat, 13 Dec 2003 09:22:37 -0800, "Chosp" wrote:
Where did you see the word diameter in the above quote. "Half the size of Earth... like Mars" seemed to me to imply he meant diameter... Perhaps bigger in this context referred to volume or mass. But perhaps it did, that's why I'm asking. If it did, that would make more sense - I could see how you might find 3 Earth masses of silicates and metals, I have a lot more trouble seeing how you might find 27. -- "Sore wa himitsu desu." To reply by email, remove the small snack from address. http://www.esatclear.ie/~rwallace |
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Planet-Formation Model Indicates Earthlike Planets Might Be Common
In order for life to evolve it needs billions of years of relative
stability. Just being the right distance from the sun doesn't provide that. Earth has stability because it has: 1. a very large moon acting as a stabaliser to the planetary wobble. 2. a very large object (Juptier) that acts as a vacuum cleaner to suck up the majority of in-coming asteroids and comets. What percentage of their simulations have that? Also, since these simulations are based on data from our solar system, and almost exclusively our solar system (since we know almost nothing about other systems), OF COURSE it is going to predict systems similar to ours. Regards, Philip |
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