Re: Life Atmosphere Basically the same everywhere? (resend)
- From: Lorentz <drosen0000@xxxxxxxxx>
- Date: Mon, 29 Dec 2008 13:48:37 -0500 (EST)
On Dec 8, 12:17=A0pm, Tom Hendricks <tom-hendri...@xxxxxxx> wrote:
On Dec 5, 12:47=3DA0pm,Lorentz<drosen0...@xxxxxxxxx> wrote:> On Dec 4, 1:=24=3D3DA0pm, Tom Hendricks <tom-hendri...@xxxxxxx> wrote:> Ther=3D
D
e seems to be a major restriction on all life that many don't conside=3D3=
t =3D
r. Only a planet about the size of Earth will hold in an atmosphere tha=
wo=3D3DJu=3D
uld lead to the origin of life. A planet with a larger atmosphere like =
pi=3D3Daving =3D
ter retains too much of the wrong gasses.
=3DA0 =3DA0 Are you sure about that? Maybe Jupiter has the exact right
atmosphere.
=3DA0 =3DA0 Also, I think you are wrong about the gravity of a planet h=
aperature
great affect on the composition of its atmosphere. All atmospheres are
unstable in an inverse square gravitational field. Eventually, all
atmospheres evaporate. The atmospheres with high molecular weight will
last longer than the ones with low molecular weight, to be sure.
=3DA0 =3DA0 =3DA0The composition would have more to do with age and tem=
Aren't the upper layers of atmosphere cold? I thought there wasthan gravity. and maybe photochemistry. Then there is volcanic
activity... The gravity is only one factor.
Temperature is important but that just adds to the argument for Earth
size.
Jupiter is too hot and wrong atmosphere.
a temperature gradient from very hot near the center to very cold in
the outer atmosphere. I think there may be a region of atmosphere
where the conditions are right for liquid water. I never heard any
astronomer talk about it, though.
I think the same may be said for Saturn and some of the other gas
giants. There may be regions where liquid water exists. Life may be
able to evolve in some region of a gas giant.
Of course, the temperature gradient increases the chance of life
developing. Complicated chemical reactions tend to occur where the
system is out of equilibrium, like in regions with strong temperature
gradients. The sulfuric acid that maintains life in the deep vents
comes from big temperature gradients in the earths mantle. You have
your obsession with UV, I have my obsession with temperature
gradients:-)
Moon is too cold and no atmosphere.I agree. Mercury is too hot and has no atmosphere...
And we need water which equals 0-100C.. Yes we need planet in the HZI think there may be such places among the moons of the gas
habitable zone, but it seems to me to be pretty much earth size too.
giants. Of course, many of these moons are approximately earth size. I
can't guarantee that the size of the planet is in any way correlated
with liquid water.
Back to a planet reasonably close to the size of earth.
.
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