?Climate on earth-type moon of extrasolar jovian?

Andrew Yee's Oct. 9th post on the Eddington Probe (could detect moons
of extrasolar planets) got me wondering...

What would be the chances of a rich earthlike biosphere evolving on an
earth-mass moon of an extrasolar jovian planet in orbit -within- the so-
called "habitable zone" of its star? This is obviously a difficult question
involving huge numbers of factors, but the first factor occurring to me as
I read that post was...what would the climate or seasons be like, since
that 'earth'-moon would have not only seasonal variations through the
year (depending on orbital eccentricity etc., axial tilt etc.), but some
variations due to its monthly changes in distance from its home star
due to its lunar orbit about the jovian.

Hmm..now that I think about it, such changes might not add up to much
since they would generally only be a tiny fraction of the planet's average
distance from its star.

Gene

"Gene Partlow" wrote in message
om...
Andrew Yee's Oct. 9th post on the Eddington Probe (could detect moons
of extrasolar planets) got me wondering...

What would be the chances of a rich earthlike biosphere evolving on an
earth-mass moon of an extrasolar jovian planet in orbit -within- the so-
called "habitable zone" of its star? This is obviously a difficult
question
involving huge numbers of factors, but the first factor occurring to me as
I read that post was...what would the climate or seasons be like, since
that 'earth'-moon would have not only seasonal variations through the
year (depending on orbital eccentricity etc., axial tilt etc.), but some
variations due to its monthly changes in distance from its home star
due to its lunar orbit about the jovian.

Hmm..now that I think about it, such changes might not add up to much
since they would generally only be a tiny fraction of the planet's average
distance from its star.


You are right, the latter would be an insignificant effect for a habitable
jovian moon orbiting a planet in the habitable zone.

The moon would also have to be (a) large enough to retain a significant
atmosphere (i.e., a lot larger than Mars but maybe not requiring to be as
large as Earth), (b) far enough from the primary not to be badly affected by
magnetic fields of the primary (in the case of Jupiter this could be a
problem unless the atmosphere is protective), (c) not affected by internal
tidal heating effects such as those that cause Io to be volcanic. The last
of these could be avoided if the large moon is the only large natural
satellite and has a circular orbit, or is orbiting a long way out, like
Callisto. Maybe one would want just enough internal tidal heating to
generate volcanic activity leading to outgassing of CO2, SO2, S2, NO2, NO,
and H2O, so that a breathable atmosphere could eventually evolve.

--
Mike Dworetsky

(Remove "pants" spamblock to send e-mail)

"Mike Dworetsky" wrote in message news:
Hmm..now that I think about it, such changes might not add up to much
since they would generally only be a tiny fraction of the planet's average
distance from its star.

You are right, the latter would be an insignificant effect for a habitable
jovian moon orbiting a planet in the habitable zone.

The moon would also have to be (a) large enough to retain a significant
atmosphere (i.e., a lot larger than Mars but maybe not requiring to be as
large as Earth), (b) far enough from the primary not to be badly affected by
magnetic fields of the primary (in the case of Jupiter this could be a
problem unless the atmosphere is protective),
Yes...the Van Allen Belt problem. I was ignoring this just to focus on the
possible monthly climate changes. While I know about as much about
chaos theory as Curly, I yet wonder if something like the much abused
butterfly effect might still apply due to the 'cumulative' effects of countless
small lunar-cycle related weather perturbations...generating something
out of proportion to the tiny individual excursions away from 'perfect'
ellipticity. ?? Very hard to say.

(c) not affected by internal
tidal heating effects such as those that cause Io to be volcanic. The last
of these could be avoided if the large moon is the only large natural
satellite and has a circular orbit, or is orbiting a long way out, like
Callisto. Maybe one would want just enough internal tidal heating to
generate volcanic activity leading to outgassing of CO2, SO2, S2, NO2, NO,
and H2O, so that a breathable atmosphere could eventually evolve.

Yes, these are good points and would seem to be necessary. A further
qualm is the Jovian itself. Jovians seem to act as system-clearers acting
on the inevitable comets and occasional asteroids. This role, due to their
huge g-fields, might put the kibosh on stable biosphere evolution since
our earth-size-moon might experience many more catastrophic collisions
than did the earth itself as these objects are deflected briefly toward the
Jovian primary.

regards, Gene

"Gene Partlow" wrote in message
om...
"Mike Dworetsky" wrote in message
news:
Hmm..now that I think about it, such changes might not add up to much
since they would generally only be a tiny fraction of the planet's
average
distance from its star.

You are right, the latter would be an insignificant effect for a
habitable
jovian moon orbiting a planet in the habitable zone.

The moon would also have to be (a) large enough to retain a significant
atmosphere (i.e., a lot larger than Mars but maybe not requiring to be
as
large as Earth), (b) far enough from the primary not to be badly
affected by
magnetic fields of the primary (in the case of Jupiter this could be a
problem unless the atmosphere is protective),
Yes...the Van Allen Belt problem. I was ignoring this just to focus on
the
possible monthly climate changes. While I know about as much about
chaos theory as Curly, I yet wonder if something like the much abused
butterfly effect might still apply due to the 'cumulative' effects of
countless
small lunar-cycle related weather perturbations...generating something
out of proportion to the tiny individual excursions away from 'perfect'
ellipticity. ?? Very hard to say.

(c) not affected by internal
tidal heating effects such as those that cause Io to be volcanic. The
last
of these could be avoided if the large moon is the only large natural
satellite and has a circular orbit, or is orbiting a long way out, like
Callisto. Maybe one would want just enough internal tidal heating to
generate volcanic activity leading to outgassing of CO2, SO2, S2, NO2,
NO,
and H2O, so that a breathable atmosphere could eventually evolve.

Yes, these are good points and would seem to be necessary. A further
qualm is the Jovian itself. Jovians seem to act as system-clearers acting

on the inevitable comets and occasional asteroids. This role, due to
their
huge g-fields, might put the kibosh on stable biosphere evolution since
our earth-size-moon might experience many more catastrophic collisions
than did the earth itself as these objects are deflected briefly toward
the
Jovian primary.


The existence of asteroid belts, Kuiper Belts and Oort clouds is not
inevitable in all systems, though probably likely. The craters on Callisto
are mostly very ancient, so maybe a biosphere can exist after a few billion
years. Every once in a while there may be an "evolution's helper" event.

--
Mike Dworetsky
(remove "pants" spamblock to send email)

"Mike Dworetsky" wrote in message ...
(b) far enough from the primary not to be badly affected by
magnetic fields of the primary (in the case of Jupiter this could be a
problem unless the atmosphere is protective),

Or its own magnetic field, one of the Jupiter moons has its own.

Would Earth's present magnetic field protect us if Earth was to
replace Ganymede or Callisto, or Europa for that matter ?


(c) not affected by internal
tidal heating effects such as those that cause Io to be volcanic. The last
of these could be avoided if the large moon is the only large natural
satellite and has a circular orbit, or is orbiting a long way out, like
Callisto. Maybe one would want just enough internal tidal heating to
generate volcanic activity leading to outgassing of CO2, SO2, S2, NO2, NO,
and H2O, so that a breathable atmosphere could eventually evolve.

So, perhaps better be in Europa's orbit than Callisto's ?

Regards

Carsten Nielsen
Denmark

"Mike Dworetsky" :

The existence of asteroid belts, Kuiper Belts and Oort clouds is not
inevitable in all systems, though probably likely. The craters on Callisto
are mostly very ancient, so maybe a biosphere can exist after a few billion
years. Every once in a while there may be an "evolution's helper" event.

On the otherhand having ringside seats to watch a ShoeMaker event would do
wonder to get people to keep a eye on the skies.

Earl Colby Pottinger

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

"Mike Dworetsky" wrote in message ...
"Gene Partlow" wrote in message
om...
Andrew Yee's Oct. 9th post on the Eddington Probe (could detect moons
of extrasolar planets) got me wondering...

What would be the chances of a rich earthlike biosphere evolving on an
earth-mass moon of an extrasolar jovian planet in orbit -within- the so-
called "habitable zone" of its star? This is obviously a difficult
question
involving huge numbers of factors, but the first factor occurring to me as
I read that post was...what would the climate or seasons be like, since
that 'earth'-moon would have not only seasonal variations through the
year (depending on orbital eccentricity etc., axial tilt etc.), but some
variations due to its monthly changes in distance from its home star
due to its lunar orbit about the jovian.

Hmm..now that I think about it, such changes might not add up to much
since they would generally only be a tiny fraction of the planet's average
distance from its star.


You are right, the latter would be an insignificant effect for a habitable
jovian moon orbiting a planet in the habitable zone.

The moon would also have to be (a) large enough to retain a significant
atmosphere (i.e., a lot larger than Mars but maybe not requiring to be as
large as Earth), (b) far enough from the primary not to be badly affected by
magnetic fields of the primary (in the case of Jupiter this could be a
problem unless the atmosphere is protective), (c) not affected by internal
tidal heating effects such as those that cause Io to be volcanic. The last
of these could be avoided if the large moon is the only large natural
satellite and has a circular orbit, or is orbiting a long way out, like
Callisto. Maybe one would want just enough internal tidal heating to
generate volcanic activity leading to outgassing of CO2, SO2, S2, NO2, NO,
and H2O, so that a breathable atmosphere could eventually evolve.


Deep-sea volcanos emit different substances:
http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif
Perhaps, the medium, into which a volcano erupts, shapes
the biosphere. For example, methane is a large component of
both the "black smokers" and Titan. John Curtis

"Carsten Nielsen" wrote in message
om...
"Mike Dworetsky" wrote in message
...
(b) far enough from the primary not to be badly affected by
magnetic fields of the primary (in the case of Jupiter this could be a
problem unless the atmosphere is protective),

Or its own magnetic field, one of the Jupiter moons has its own.

Would Earth's present magnetic field protect us if Earth was to
replace Ganymede or Callisto, or Europa for that matter ?


Earth's magnetic field undergoes reversals, and during these the
"protective" effect is much reduced. Jupiter's magnetic field is much
stronger than Earth's, even at large distances from the planet. The main
thing that has to be protected against is charged particles and solar wind.
Jupiter has a lot of charged particles in its field.


(c) not affected by internal
tidal heating effects such as those that cause Io to be volcanic. The
last
of these could be avoided if the large moon is the only large natural
satellite and has a circular orbit, or is orbiting a long way out, like
Callisto. Maybe one would want just enough internal tidal heating to
generate volcanic activity leading to outgassing of CO2, SO2, S2, NO2,
NO,
and H2O, so that a breathable atmosphere could eventually evolve.

So, perhaps better be in Europa's orbit than Callisto's ?


Possibly. If the body is large enough and made of the right materials, like
Earth, it will have volcanism all by itself, so it could be at a much larger
distance.

--
Mike Dworetsky

(Remove "pants" spamblock to send e-mail)