Solar Wind and Venus' Atmosphere
hemo_jr
have stated that the Earth's atmosphere would be eroded -- to the
extent seen on Mars -- if the Earth did not have a strong
magnetosphere.
This leaves me with the question -- conveniently ignored by those same
programs -- Venus has no magnetosphere, so why has its atmosphere not
even more sparse than Mars? After all the solar wind on Venus should
be (hundreds?) of times stronger on Venus than Mars. So it seems
somewhat disingenuous of the writers and producers not explain Venus
when they are comparing Mars to Earth.
Perhaps the only thing that the solar wind has been able to erode from
Venus' atmosphere is its hydrogen and oxygen.
--
Matt Hickman
windbag
due to constant gravitational pressure -- as opposed to Earth, which
had its early, cataclysmic lunar-formational event) it may be
replenishing its carbon dioxide, etc., at a rate much higher than its
solar erosion quotient.
If we knew how much atmosphere Mercury started with, at the time of
solar ignition, then rates of atmospheric erosion might be pinned down
more precisely. However, as it is, Earth seems to be a special case
with its plasma tail getting hooked around by the moon and its vast
open seas.
As for Mars, the mysteries still appear open-ended. If there actually
was a thicker atmosphere at some point, something must have happened
to it. From looking at features like the Tharsis vents, and the Hellas
impact, more possibly was involved than mere sublimation and solar
winds...
hemo_jr
> Since Venus appears to have a more molten interior than Earth (perhaps
> due to constant gravitational pressure -- as opposed to Earth, which
> had its early, cataclysmic lunar-formational event) it may be
> replenishing its carbon dioxide, etc., at a rate much higher than its
> solar erosion quotient.
Thanks. With a more molten interior than Earth, one would expect that
Venus would also have experienced an iron catastrophe like Earth
apparently did and therefore have an iron core. The nearly non-
existent magnetosphere can be blamed on the slowness of the
planetary rotation? Or is current thinking that Venus does not have
an iron core?
BradGuth
Venus is not as old as Earth, and as such it's still extremely
geothermal and unavoidably venting S8 and Co2 like crazy, and
obviously spewing muds and lava along with releasing some of its h2o.
Perhaps Venus once had a moon of roughly 7.35e22 kg.
~ Brad Guth Brad_Guth Brad.Guth BradGuth
BradGuth
There's most likely a core of iron, or perhaps even along with its
fair share of thorium.