neutrino wrote:
as per -http://www.news.com/2300-11397_3-6237061-1.html?tag=newsmap
and
NASA's Mars Reconnaissance Orbiter used its High Resolution Imaging
Science Experiment (HiRISE) camera to take the sharpest images ever of
the Martian moon Phobos, and viewing this image of Phobos.....
wouldnt it be more accurate to classify Phobos as an asteroid that has
been captured ito Mars orbit, rather than a "moon"?  I tend to imagine
a "moon" as a mini planet that formed in much the way the larger
planets formed, Phobos on the other hand with it's irregular shape
makes me think of it more as you might an asteroid - but in this case
it got itself caught up in an orbit around Mars. (or perhaps it's the
remains of a comet?  not moving fast enough to flyby Mars - slow
enough to be captured into orbit?)

A moon is an object that circumnavigates a planetoid with some extended degree
of regularity.

Phobos may have once been an asteroid, but it is now a moon.
--
ah

as per - http://www.news.com/2300-11397_3-6237061-1.html?tag=newsmap
and
NASA's Mars Reconnaissance Orbiter used its High Resolution Imaging
Science Experiment (HiRISE) camera to take the sharpest images ever of
the Martian moon Phobos, and viewing this image of Phobos.....
wouldnt it be more accurate to classify Phobos as an asteroid that has
been captured ito Mars orbit, rather than a "moon"? I tend to imagine
a "moon" as a mini planet that formed in much the way the larger
planets formed, Phobos on the other hand with it's irregular shape
makes me think of it more as you might an asteroid - but in this case
it got itself caught up in an orbit around Mars. (or perhaps it's the
remains of a comet? not moving fast enough to flyby Mars - slow
enough to be captured into orbit?)

as per - http://www.news.com/2300-11397_3-6237061-1.html?tag=newsmap
and
NASA's Mars Reconnaissance Orbiter used its High Resolution Imaging
Science Experiment (HiRISE) camera to take the sharpest images ever of
the Martian moon Phobos, and viewing this image of Phobos.....
wouldnt it be more accurate to classify Phobos as an asteroid that has
been captured ito Mars orbit, rather than a "moon"? I tend to imagine
a "moon" as a mini planet that formed in much the way the larger
planets formed, Phobos on the other hand with it's irregular shape
makes me think of it more as you might an asteroid - but in this case
it got itself caught up in an orbit around Mars. (or perhaps it's the
remains of a comet? not moving fast enough to flyby Mars - slow
enough to be captured into orbit?)

as per - http://www.news.com/2300-11397_3-6237061-1.html?tag=newsmap
and
NASA's Mars Reconnaissance Orbiter used its High Resolution Imaging
Science Experiment (HiRISE) camera to take the sharpest images ever of
the Martian moon Phobos, and viewing this image of Phobos.....
wouldnt it be more accurate to classify Phobos as an asteroid that has
been captured ito Mars orbit, rather than a "moon"? I tend to imagine
a "moon" as a mini planet that formed in much the way the larger
planets formed, Phobos on the other hand with it's irregular shape
makes me think of it more as you might an asteroid - but in this case
it got itself caught up in an orbit around Mars. (or perhaps it's the
remains of a comet? not moving fast enough to flyby Mars - slow
enough to be captured into orbit?)

Painius My thinking is when a moon is first captured its orbit gets
rounder in time. I see no good reason why a moon would break up and
create rings. I can see 3.5 billion years ago a dirty snow ball comet
on the verge of being captured breaking up but having the right angle to
put its rock and ice in orbit. I can relate that to the Shoemaker comet
breaking up before angling in to hit Jupiter (not the right angle)
Bert

"neutrino" <stua...@bluebottle.com> wrote in message

news:81eab342-ae55-4a3d-836d-d673e6d2c731@z24g2000prf.googlegroups.com...

as per -http://www.news.com/2300-11397_3-6237061-1.html?tag=newsmap
and
NASA's Mars Reconnaissance Orbiter used its High Resolution Imaging
Science Experiment (HiRISE) camera to take the sharpest images ever of
the Martian moon Phobos, and viewing this image of Phobos.....
wouldnt it be more accurate to classify Phobos as an asteroid that has
been captured ito Mars orbit, rather than a "moon"? I tend to imagine
a "moon" as a mini planet that formed in much the way the larger
planets formed, Phobos on the other hand with it's irregular shape
makes me think of it more as you might an asteroid - but in this case
it got itself caught up in an orbit around Mars. (or perhaps it's the
remains of a comet? not moving fast enough to flyby Mars - slow
enough to be captured into orbit?)

Seems that the definition of a "moon" should also imply "round", as in
having formed from molten materials and cooled into a sphere.
Phobos (22km long) with a huge crater hole at one end and Deimos (12km) both
look like Idaho spuds, tumbling around Mars in a drunken stupor. In all
likelihood they are Asteroid Belt objects, ejected long ago by a gentle
nudge from another asteroid, which then careened off in Jupiter's direction.
Somewhere I read that their orbit are getting increasingly closer to Mars
and they will eventually impact there, with a loudish kaboomer and
spitzensparken.

"BradGuth" <bradg...@gmail.com> wrote in message...

news:702cd120-815a-4e2c-b733-248aa3d044e7@h1g2000prh.googlegroups.com...



What ever happened to the big old moon of Venus?

I think it was the exact same size and mass as our moon.
. - Brad Guth

It would have been truly great if Venus had had such
a moon all along. Because if Venus had had a moon
like ours, the ancients would have been able to see
it with their naked eyes. And geocentrism would have
been dashed to pieces before it could have gotten a
foothold in the minds of astronomers.

happy days and...
starry starry nights!

--
Indelibly yours,
Paine

P.S. Thank YOU for reading!

P.P.S. (shh) Some secret sites...
http://painellsworth.net
http://savethechildren.org
http://eBook-eDen.secretsgolden.com

"G=EMC^2 Glazier" <herbertglaz...@webtv.net> wrote...

in messagenews:11826-47FF779E-284@storefull-3333.bay.webtv.net...



Painius My thinking is when a moon is first captured its orbit gets
rounder in time. I see no good reason why a moon would break up and
create rings. I can see 3.5 billion years ago a dirty snow ball comet
on the verge of being captured breaking up but having the right angle to
put its rock and ice in orbit. I can relate that to the Shoemaker comet
breaking up before angling in to hit Jupiter (not the right angle)
Bert

Well Bert, i'd like to know why you think that any
orbit would get more circular over time. I'm not
saying that you're wrong, because there might
very well be some natural kind of synchronization
at work that does this. My gut feeling is that the
different types of orbits, from almost circular to
very eccentric, are all pretty stable over long
periods of time (unless some cataclysm takes
place).

Hopefully, you can see that even if we put aside
the fact that both Phobos and Deimos orbit Mars
in almost perfect circles, they both also orbit only
about 1 degree off of Mars' equator. This is a
definite clue that both satellites formed at the
same time and in the same whorl that planet Mars
formed in.

A captured asteroid would most likely be coming
from the asteroid belt and would probably be very
near the plane of the ecliptic. Both Phobos and
Deimos orbit Mars fully 26 to 28 degrees *off* the
plane of the ecliptic.

So until we know more, i have to accept that both
Phobos and Deimos are natural satellites of Mars,
and not captured asteroids.

Okay, you say that you see no good reason why a
satellite would break up and form rings. Well, in a
bit over 100 million years, the satellite nearest to
Mars, Phobos, is expected to come close enough
to Mars to do just that! Phobos' orbit is decreasing
due to tidal forces. Now, i know you know about
the "Roche limit". Phobos' degrading orbit will take
the satellite within the Roche limit of Mars in just
over 100 million years. At that time Phobos is
expected to be broken into rubble by tidal forces
and form short-lived rings around Mars. The dust
and debris that make up the rings will eventually
fall to the surface of the planet.

Some scientists say that because Phobos quickly
zips aroung Mars, it just might stay together all
the way down until it hits the surface of Mars. But
most people think this is unlikely. It's more likely
that Phobos will fall prey to the Roche limit and
break apart to form rings around Mars.

And you might make note that all the rings of the
planet Saturn are within the Roche limit of that
planet!

Deimos is far enough from Mars that the tidal
forces work the same way Earth and Selene work
on each other. So Deimos is slowly "leaving" the
planet Mars...

as per - http://www.news.com/2300-11397_3-6237061-1.html?tag=newsmap
and
NASA's Mars Reconnaissance Orbiter used its High Resolution Imaging
Science Experiment (HiRISE) camera to take the sharpest images ever of
the Martian moon Phobos, and viewing this image of Phobos.....
wouldnt it be more accurate to classify Phobos as an asteroid that has
been captured ito Mars orbit, rather than a "moon"? I tend to imagine
a "moon" as a mini planet that formed in much the way the larger
planets formed, Phobos on the other hand with it's irregular shape
makes me think of it more as you might an asteroid - but in this case
it got itself caught up in an orbit around Mars. (or perhaps it's the
remains of a comet? not moving fast enough to flyby Mars - slow
enough to be captured into orbit?)

Painius My thinking is when a moon is first captured its orbit gets
rounder in time. I see no good reason why a moon would break up and
create rings. I can see 3.5 billion years ago a dirty snow ball comet
on the verge of being captured breaking up but having the right angle to
put its rock and ice in orbit. I can relate that to the Shoemaker comet
breaking up before angling in to hit Jupiter (not the right angle)
Bert

What ever happened to the big old moon of Venus?

I think it was the exact same size and mass as our moon.
. - Brad Guth