Mars once had atmosphere ... why not now?

OK. So NASA has evidence that Mars once had lakes/seas of water. This
means it was warmer and had more of an atmosphere at some point in the
past. Why then and not now? What changed? Can it happen to earth?

Your thoughts are appreciated.

MarsMud wrote:

OK. So NASA has evidence that Mars once had lakes/seas of water. This
means it was warmer and had more of an atmosphere at some point in the
past. Why then and not now? What changed? Can it happen to earth?

Your thoughts are appreciated.


i read last year what i thought to be well considered conjecture that
the lack of a protective magnetic field allows the solar wind to strip
the atmosphere over time.
i no longer remember the source though wish i did. it's a thought anyway.

g

--
In Italy for thirty years under the Borgias they had warfare,
terror, murder and bloodshed but they produced Michelangelo,
Leonardo da Vinci and the Renaissance. In Switzerland, they
had brotherly love; they had five hundred years of democracy
and peace and what did that produce? The cuckoo clock.
-- Orson Welles (1915 - 1985), The Third Man, 1949

MarsMud wrote:

OK. So NASA has evidence that Mars once had lakes/seas of water. This
means it was warmer and had more of an atmosphere at some point in the
past. Why then and not now? What changed?

Mars atmosphere is mostly CO2 and CO2 can be bound at low temperatures
near the poles in the soil and in the polar ice cap.
When the obliquity of the mars axis increases the poles get warmer and
the atmosphere gets thicker and the whole Mars gets warmer which releases
more CO2 and Mars gets into an other warmer stable state with thicker atmosphere.


Can it happen to earth?
Earth Atmosphere ist Nitrogen , so the density is not much influenced,
but the ice ages are caused by similar effects.

--
http://www.geocities.com/carla_sch/index.html

So Mars once had a stronger magnetic field?

glowell wrote:

MarsMud wrote:

OK. So NASA has evidence that Mars once had lakes/seas of water. This
means it was warmer and had more of an atmosphere at some point in the
past. Why then and not now? What changed? Can it happen to earth?

Your thoughts are appreciated.


i read last year what i thought to be well considered conjecture
that the lack of a protective magnetic field allows the solar wind to
strip the atmosphere over time.
i no longer remember the source though wish i did. it's a thought
anyway.

g

MarsMud wrote in news:AZn1c.55925$A12.11752
@edtnps84:

OK. So NASA has evidence that Mars once had lakes/seas of water. This
means it was warmer and had more of an atmosphere at some point in the
past. Why then and not now? What changed? Can it happen to earth?

Your thoughts are appreciated.


Much of the atmosphere of Mars probably slowly leaked away into space.
The Earth isn't as prone to this sort of leakage, as it has a
considerably higher escape velocity. The Earth will probably end up a bit
like Venus in a billion years or so, because the sun is gradually getting
hotter as it progesses along its' main sequence evolution. About four
billion years after that, the sun will puff up into the red giant stage
as it commences helium burning. The earth's orbit will probably move
outward somewhat to compensate for the solar mass loss as it evolves into
a red giant, assuming it doesn't get absorbed by the sun's atmosphere
first.

Llanzlan.

Hej Llanz,

Why is Earth's magnetic field pole shift 200K years delayed? Maybe OUR
magnetic field is weakening quickly and our atmosphere is about to be
blown off, and we'll have to migrate (maybe for the third time) to
another planet that "looks too hot" and "couldn't possibly harbor life".
I guess we just have to redirect as many incoming comets onto Venus'
surface and wait a few hundred k years, and create a Noah's Ark, and
hunker down in the meantime.

JS



Llanzlan Klazmon The 15th wrote:

Much of the atmosphere of Mars probably slowly leaked away into space.
The Earth isn't as prone to this sort of leakage, as it has a
considerably higher escape velocity. The Earth will probably end up a bit
like Venus in a billion years or so, because the sun is gradually getting
hotter as it progesses along its' main sequence evolution. About four
billion years after that, the sun will puff up into the red giant stage
as it commences helium burning. The earth's orbit will probably move
outward somewhat to compensate for the solar mass loss as it evolves into
a red giant, assuming it doesn't get absorbed by the sun's atmosphere
first.

Llanzlan.

Joe Schmoe wrote in
:

Hej Llanz,

Why is Earth's magnetic field pole shift 200K years delayed? Maybe
OUR magnetic field is weakening quickly and our atmosphere is about to
be blown off, and we'll have to migrate (maybe for the third time) to
another planet that "looks too hot" and "couldn't possibly harbor
life".
I guess we just have to redirect as many incoming comets onto Venus'
surface and wait a few hundred k years, and create a Noah's Ark, and
hunker down in the meantime.

JS


Venus shows no sign of losing its' atmosphere even though it has
practically no intrinsic magnetic field. Observations direct from mother
nature always trump speculation.

Llanzlan.







Llanzlan Klazmon The 15th wrote:

Much of the atmosphere of Mars probably slowly leaked away into
space. The Earth isn't as prone to this sort of leakage, as it has a
considerably higher escape velocity. The Earth will probably end up a
bit like Venus in a billion years or so, because the sun is gradually
getting hotter as it progesses along its' main sequence evolution.
About four billion years after that, the sun will puff up into the
red giant stage as it commences helium burning. The earth's orbit
will probably move outward somewhat to compensate for the solar mass
loss as it evolves into a red giant, assuming it doesn't get absorbed
by the sun's atmosphere first.

Llanzlan.

You completely missed what I was saying, dumbass. Ask anyone here.

JS

Llanzlan Klazmon The 15th wrote:

Joe Schmoe wrote in
:


Hej Llanz,

Joe Schmoe wrote:
You completely missed what I was saying, dumbass. Ask anyone here.

Maybe, but what he said was more a more interesting observation than any
of the sci-fi crap you gave us and he *definitely* didn't call anyone a
dumbass with little reason.


--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)

SkyTools Software for the Observer:
http://www.skyhound.com/cs.html

Skyhound Observing Pages:
http://www.skyhound.com/sh/skyhound.html

To reply remove spleen

"Joe Schmoe" wrote in message
...
Hej Llanz,

Why is Earth's magnetic field pole shift 200K years delayed? Maybe OUR
magnetic field is weakening quickly and our atmosphere is about to be
blown off, and we'll have to migrate (maybe for the third time) to
another planet that "looks too hot" and "couldn't possibly harbor life".
I guess we just have to redirect as many incoming comets onto Venus'
surface and wait a few hundred k years, and create a Noah's Ark, and
hunker down in the meantime.


Paleomagnetic evidence tells us that the magnetic reversals do not occur at
strictly regular intervals, and that when they do, the duration of "zero
field" is short compared to the duration of "strong field". Even when the
field reverses, there is a net local field here and there due to the
self-excited dynamo in the Earth's iron core; its average value is
approximately zero for a while (+ in some locations; - in others), but
locally it may not be zero.

It would take a very long time for the relatively weak solar wind to strip
off the entire atmosphere (many millions of years). When the solar system
was very young, the wind was probably a lot stronger and had a significant
effect.

The fact that there is no evidence that the Earth has ever lost its
atmosphere in the past 3-4 billion years may be some comfort to you. :-)

--
Mike Dworetsky

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