Phobos over Mars

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Nereid
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Not the PF Mentor!

Very cool pic, from the Viking 2 spacecraft, of the Martian moon Phobos over the volcano, Ascraeus Mons.
http://antwrp.gsfc.nasa.gov/apod/ap031129.html

Nice visual perspective on how big this moon is, how large the shield volcano is. For comparison, many a comet is about the same size as Phobos, and the smallest moons of Uranus discovered so far are about this size too.
 

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Originally posted by Nereid
Not the PF Mentor!

Very cool pic, from the Viking 2 spacecraft, of the Martian moon Phobos over the volcano, Ascraeus Mons.
http://antwrp.gsfc.nasa.gov/apod/ap031129.html

Nice visual perspective on how big this moon is, how large the shield volcano is. For comparison, many a comet is about the same size as Phobos, and the smallest moons of Uranus discovered so far are about this size too.
That is a cool picture.

Phobos is one of the smallest moons in the solar system only larger than: Deimos, Leda, Adrastea, and Pan.

orbit: 9378 km from the center of Mars
diameter: 22.2 km (27 x 21.6 x 18.8)
mass: 1.08e16 kg

And Phobos is doomed: because its orbit is below synchronous altitude tidal forces are lowering its orbit, right?

Nereid, do you believe that Phobos came from the outer solar system rather than in the main asteroid belt? Because I heard there is speculation among scientists on that issue and I would just like to hear your perspective.
 
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Nereid
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hard to keep up!

Hi Jeebus.

I read the reports with great interest, many years ago now it seems. Sorry to say I've not kept up with developments here, so I don't really have an opinion.

However, I expect there are many nice surprises in store for us as we tease out the 'dynamic' nature of the solar system - the origin of Saturn's, Uranus', Neptune's rings; of short period comets; the collisional frequency (and history?) of objects in the main asteroid belt, of those in chaotic orbits; the nature of the Oort cloud; ...

I'm not sure how often they keep it updated, but this Sky&Telescope website is the best I've found on planetary satellites:
http://skyandtelescope.com/observing/objects/planets/article_827_1.asp

For minor planets, comets, etc, nothing beats the Minor Planet Center, though the information is very dense.
http://cfa-www.harvard.edu/cfa/ps/mpc.html [Broken]
 
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Phobos
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What?!? There's a moon named after me?
Cool!

yes, I'm kidding
 

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