I too have heard about ice on the moon. I read scientists believe it
comes from comets that hit it.
They are plentiful.
From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of terrierkeeper
> I read scientists believe it comes from comets that hit it.
>
> Why not use comets as the source for water?
>
> They are plentiful.
Unfortunately, most comets are on high-eccentricity orbits, which makes
them expensive to rendezvous with and to get material to Earth orbit.
On the other hand, it's speculated that many NEAs may be the burnt-out
cores of former comets. So the distinction between going to a
somewhat-less-active comet and going to a NEA might be a gray area.
Regards,
Mike Combs
NEAs are basically comets, but after millions or billions of years of
being too close to the Sun, most of the Ice has sublimated into vapor
and been blown out by the solar winds (hence the comet's tail).
Sublimation is like evaporation, except the ice goes from solid
straight to gas. NEAs are therefore mostly rock and metal. The more
time an object spends inside Jupiter's orbit, the less water is has.
Visits by Kuiper and Oort Comets are rare and intermittent, and
therefore probably not a reliable source of water. Of course there is
good research being done right now that should further clarify the
water content of specific asteroids and comets. Maybe we'll get
lucky.....
On Oct 27, 2006, at 11:31 AM, Combs, Mike wrote:
I should point out that the reason Earth has so much water despite
being within Jupiter's orbit is due to our huge gravity. Asteroiods
have small gravity, and therefore the solar winds have been powerful
enough to blow their water away. Mars has more gravity than
asteroids, but still not enough to hold on to most of its water. Its
pretty obvious that most of Mar's northern hemisphere was once ocean,
but now its gone. most NEA's lost most of their water and ice about 4
billion years ago.
On Oct 27, 2006, at 11:31 AM, Combs, Mike wrote:
On 10/27/06, Douglas May wrote:
(...)
> I should point out that the reason Earth has so much water despite
> being within Jupiter's orbit is due to our huge gravity. Asteroiods
> have small gravity, and therefore the solar winds have been powerful
> enough to blow their water away. Mars has more gravity than
> asteroids, but still not enough to hold on to most of its water. Its
> pretty obvious that most of Mar's northern hemisphere was once ocean,
> but now its gone. most NEA's lost most of their water and ice about 4
> billion years ago.
(...)
billions of years. (http://www.newscientist.com/article.ns?id=dn4136)
Sadly, though, as the Sun got older and hotter the planet eventually
reached runaway greenhouse conditions, and water converted in vapor
was photodissociated by the sun in the coming aeons.
Of course too much gravity may represent the other extreme of the
"water problem". (Under a human standpoint. For life as a whole liquid
water is always good, I would say.) Before Super-Earths were
discovered, simulations pointed out that planets "weighting" a few
earth masses are possible, but they would likely be covered by global
oceans many kilometers deep.
I took this picture out the back door of my house next to Otis air force
base on cape cod, ma. with a disposable camera. this would be the second one I
have seen. the first one I was with my then 12
(http://aolsvc.pictures.aol.com/NASApp/ygp/Start?event=DirectPictureView&shareInfo=mFQYMXJcDsV6XlrwwjDkVZJiH
xM3JWtimXc1R1EDldh76ebX7zvmrc7pyg28G5lMhjPZqxwshcM0
qQMLGj+nlHpeWvDCMORVEYyPK5XqONI=&pageName=AlbumViewFromEmails) who also saw
what we could not explain.
with your message and the picture i took next to otis air force base on cape
cod, ma. one can only wonder just how old civilization is? i have seen two
of these or one of two different kinds. the first was a ball that glowed
when driving down the canal of cape cod with my then 12 yr. old daughter we both
looked at each other saying at the same time, did you see that? which is
how i knew i was not seeing things.
you be the judge as to what this is. i have researched this type i believe
this has been worked on since the 60's, a proto type of something found per
general who ordered this made.
hcPV
n2hwaF3EIHpeWvDCMORVEEU4IhqdAdQ=&pageName=AlbumViewFromEmails)
and with that said one can only imagine how old humanity is. I having seen
this fly over my house next to Otis air force base and being the second of
such flying objects though hidden from common man I wonder, just how old and far
life has come?
(http://aolsvc.pictures.aol.com/NASApp/ygp/Start?event=DirectPictureView&shareInfo=mFQYMXJcDsV6XlrwwjDkVcHmwsTzQylxTi3b0gVOQNx76ebX7zvmrc7p
yg28G5lMhjPZqxwshcOJ
A+6ka51ffHpeWvDCMORVJO8B4j78Dvs=&pageName=AlbumViewFromEmails)
dismiss the last e mail i see now. so hurried to read all the mail sorry.
sorry i am unable to get to the site you referred me to in your e mail. i
have notified AOL. your e mail did say non text portions have been removed.
why is that? might you know?