[pasmembers] Re: Life Beyond Earth
- From: "Peter Turner" <peteturner@xxxxxxxxxxx>
- To: <pasmembers@xxxxxxxxxxxxx>
- Date: Mon, 25 Aug 2014 12:10:46 -0700
It appears, based on information obtained by the Herchel Space Observatory in
2011, that some comets do contain similar isotopes of water to Earth’s water.
Also, the Oort Cloud comets may have formed inside the solar system and
gravitated outward. The Jupiter comets may have been created in the Kuiper
Belt and gravitated inward. However a lot of this is still up in the air.
http://sci.esa.int/herschel/49386-herschel-finds-first-evidence-of-earth-like-water-in-a-comet/.
Also, most of the water that outgases from today’s volcanos is determined to
have come from the oceans via plate-tectonics and from ground-water. While
water is the most prevalent of volcanic gases now, it may not have been in the
earth’s beginning.
Peter Turner
MaidPro North-Phoenix
19235 N Cave Creek Rd #106
Phoenix, AZ 85024
602.765.1964
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Sent: Monday, August 25, 2014 9:43 AM
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Subject: [pasmembers] Re: Life Beyond Earth
Had to put my two cents in. Once the sun ignited it has varied little in
output. Inside of Jupiter's orbit we have asteroids and zodiacal light which is
dust not ices because of the stellar wind and light intensities. Even now this
slowly strips rocky planets of their atmospheres and left only the heavier
gases (no H & He). Comets begin to sublimate when they get closer than Jupiter
and quickly lose their mass. Objects like the Earth are a very small target.
The most important point against comets is because they formed outside our
solar system they have isotopic ratios that do not match terrestrial values.
Only Io is too hot to have ice of all the moons of the gas giants. Isotope
ratios of ice on these moons are much closer to terrestrial values. Asteroids
beyond Jupiter are also ice covered but not as thick as these moons. These
satellites had close encounters with other moons that reversed the orbits of
the smaller moon and would eject the more massive moon. I have given lectures
on how the Earth was struck 1.8 billion years ago in the Pacific by a moon of
Neptune that had a thick layer of ice and hydrocarbons that made it as large as
Mars. You can double the amount of water the Earth has because the Moho is a
buried mineralized ocean that is still trying to reach the surface through
volcanics.
Mike Marron
_____
From: "Robert Ewing" <rrewing9@xxxxxxxxx>
To: pasmembers@xxxxxxxxxxxxx
Sent: Sunday, August 24, 2014 8:02:10 PM
Subject: [pasmembers] Re: Life Beyond Earth
Sorry I forgot to mention that as the Earth was forming (early on) comets could
have struck it and incorporated water into the Earth as well...the Earth would
have to have accumulated enough mass however so that the escape velocity for
water molecules would not be exceeded.....because the temperature was not cold
at that point......hence difficult for liquid or ice to accumulate here......
On Aug 24, 2014 7:53 PM, "Robert Ewing" <rrewing9@xxxxxxxxx> wrote:
Hey. Bob Ewing here, from PVCC.....
I have always had a difficult time with the comet theory as well, because, the
Earth has been outgassing for 4 billion years plus; (ie: volcanic activity); so
there had to be primordial water inside the Earth from it's formation from the
solar nebula; although maybe in the form of vapor.
H2O is actually a very common molecule in space. But, the Earth has been struck
by many comets as well, so certainly some of the water has come from them
......hard to say what %
Volcanoes emit steam (water) as the primary gas. CO 2 is usually second.
There are hydrated minerals too and maybe some of these have been recycled
inside the Earth over time, as has sediment containing water (marine). When
this material is melted inside the Earth they would release the water as
steam...
Complicated issue!
:-)
Bob
On Aug 24, 2014 5:26 PM, "Alex Vrenios" <axv@xxxxxxx> wrote:
I just happened to watch the NOVA program, "Finding Life Beyond Earth." The
focus seemed to be on some new thinking about how an exoplanet doesn't have to
be in a "sweet spot," at that not-too-hot and not-too-cold distance from it's
star, to foster life. There are other energy sources, like geothermal, e.g.,
that can suffice, admitting many other, more distant planets and moons to the
potentially inhabited bodies in a solar system. A source of energy, water and
organic compounds were referred to as the "trifecta" of life-forming
ingredients.
Pretty cool, but what caught my interest was the water.
A long time ago, a budding young scientist (in a geology class, I think) asked
one of those questions that stop internationally acclaimed scientists in their
tracks, "Where did all that water come from?" Referring to the fact that about
3/4 of the Earth's surface is covered with water, yet there doesn't seem to be
a reason for that.
The answer for many years has been a bombardment from comets which, as we all
believe, are made mostly of ice: the "dirty snowballs" of stellar objects. I
think that that's a lot of comets! It never seemed to me to be a very
satisfying solution, no pun intended.
This NOVA program referred to an accretion disc as dust, gas and water.
Wikipedia's definition is too vague. Britanica.com <http://britanica.com/>
says "dust, gas and other tangled molecules." I don't remember hearing anyone
state that water was a major component of the material from which planets may
form before now. But then I'm not exactly a main-stream astrophysicist, so
maybe some of you can elaborate...
Alex
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