[pasmembers] Re: Life Beyond Earth
- From: Robert Ewing <rrewing9@xxxxxxxxx>
- To: pasmembers@xxxxxxxxxxxxx
- Date: Sun, 24 Aug 2014 19:53:47 -0700
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 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
>
Other related posts:
