The Millennium Group and other woowoo outfits (including some of Nancy Lieder's followers) have been clamoring that Phobos has disappeared. The Mars Global Surveyor, however, just got these shots showing Phobos right where it should be. That is, of course, if you trust NASA. :roll:

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Phil Plait
The Bad Astronomer
http://www.badastronomy.com
badastro@badastronomy.com

You mean Phobos is actually there! Are you implying that the Millenium Group might not know what they're talking about? :wink:

I seem to recall there was a thread about this back during that Comet Neat thing. I'll have to find it later and see what Comet Neat doomsayers had to say - and what their 'evidence' was that Mars' Moons were gone.

I think it would be cool if Earth had a little spud moon like Phobos, in a relatively low orbit so it would rise and set several times a day. I doubt such an object would remain in a stable orbit for long, though, what with Lunar tides and all. Maybe you get to pick one of (a) one large moon, or (b) several small moons.

Unless you're a gas giant, that is... 8)

I hope a foolish question will be excused but what is the current theory on the origin of Phobos (and Deimos come to that)? Are they captured asteroids ?

That's my understanding. IIRC, they're considered to be "temporary" moons -- eventually they'll decay, break up, and impact.

Here's the thread I was referring to: The Moons of Mars are Missing? It looks like it was a discussion of the Millenium Group's claims - starring chaiyah (remember her?)

that's right...Phobos is gone and I'm taking its place!

She's a regular over at Godlike - and even some of the folks over there think she's lost it.

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Everything I need to know I learned through Googling.

Actually, they were missing. Ba took them in for cleaning. Deimos especially was filthy. But Ba had them nicely cleaned and polished, and put them right back where they were. He's sorry if anyone was worried during their absence. Please forgive the inconvenience.

At least this new Phobos has the sense to get online and come to the BABB

If I hear any reports from TMG that you've gone missing I'll let you know.

That would be much appreciated.

actually, my press agent sends these scares now and then to the millenium groups just to keep my name in the papers

Didn't someone crunch the numbers a while back and work out that Phobos has about 37000 years before it takes the plunge?

Thanks for the link, BA, I was actually just discussing this last week with somebody over on the Other Forum. However, I doubt whether a picture of a tiny white speck is going to convince him--I can hear him now, "But it doesn't LOOK like a moon!"

Oh well.

The same link has a closeup picture taken with the hi-res camera at the same time.

Is Phobos where you store the fruit pies?

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If you can't dazzle 'em with dexterity, baffle 'em with BS.

From the Spaceref.com webpage: "To a person standing on Phobos, the red planet would fill most of the sky." That would be a marvelous view! Here's a painting done in 1930 by Russell Butler:


I think Dixon and Bonestell also imagined this view. (Dixon without the canals. :wink: ) Someday, we'll get an image from a lander, and maybe someday, someone will actually stand there.

I was wondering: if an astronaut plus their spacesuit weighed 250 pounds on Earth, how much would they weigh on Phobos? They would probably have to "walk" with care.

Bonestell definitely did, as I have the picture in front of me right now. I don't see any canals, but there seem to be lakes. He also have astronauts floating around on Phobos' surface.

The latest issue (August) of Sky & Telescope has a good article on looking for Mars' moons during the upcoming opposition. Assuming, of course, that they're there. :wink:

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I like crinoids.

Bonestell's version:

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Everything I need to know I learned through Googling.

Cool! Bonestell has always been one of my favorites.

The Phobos art gallery continues with this fine one by Bergeron too! :wink:

Thanks, ToSeek. I was looking at another one he did of Mars seen from Phobos (that's the title of the work, incidentally).

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I like crinoids.

Beat me to it, just read the article this evening. It looks like those of you with 10 inch and larger scopes stand a better chance of seeing them than me, though they have apparently been sighted with scopes smaller than 8 inches.

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If you can't dazzle 'em with dexterity, baffle 'em with BS.

But be careful what you wish for! I thought it might be good to have two of them in orbit to serve as "shepherds" for our space junk, but realized it would be irresponsible to put large objects that close to Earth when there is no guarantee that we will be around long enough to keep them from falling and creating another catastrophe like the Cretaceous-Tertiary one.

A few hundred years from now an asteroid that is co-orbiting with us (can't remember the name, sorry ) will appear to orbit Earth for a few revolutions, though at some distance.

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Microsoft is over if you want it.

The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.

Is that the one in the horse-shoe orbit?

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Quaeso quousque humi defixa tua mens erit? Nonne aspicis, quae in templa veneris?

Yes, that's what I was trying to imply with my comment about the stability of the spuds.

But let's consider the idea of putting up some shepherds. Very low orbit is out of the question, for the reason you gave. While we might argue that we'll go up and give it a boost if it threatens to fall, we can't be sure the capability will always be there (think Challenger and Columbia).

How about a high one, in a three-orbits-a-day position? That would be a lot stabler, and if we lost the ability to get to it we'd have a lot of time to recover. If we didn't, we probably wouldn't be around to worry about the consequences of the impact. OTOH, it wouldn't do much good for the space junk problem way up there.

Who's theory was it that Phobos was hollow (as in "artificial") ?? Mariner 9 was the 1st probe to image the spud for our conspirators eyes and if my memory is faithful despite my advanced fossillating brain, the ppl at JPL including Carl Sagan first thought there was a hole right through Phobos after seeing the unprocessed image that showed a star-like dot right in the middle of a crater (Stinkney ? )
I was observing the approaching Mars earlier this morning and couldn't help wondering what johnatan Swift(gulliver's travels) or Lowell would think of the swarm of probes heading there right now.
6 months to wait still so lots of time for wandering thoughts

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The Great French-Canadian Escaped Mental Patient

The artificial Phobos theory didn't start life as a crank idea. It was first proposed in 1959 by I S Shklovskii, a well-respected Russian astrophysicist. Shklovskii went on to co-write Intelligent Life in the Universe (1966) with none other than Carl Sagan (interesting how he pops up in this context - the book is a classic, by the way, and still repays reading).

Shklovskii sought to explain an apparent steady increase in the orbital velocity of Phobos - detected by US astronomer B P Sharpless in 1945 - as evidence that is was of very low mass, therefore probably hollow, therefore probably artificial. Sharpless' figures have since been found to be in error, and there is no further need of such a theory (although Phobos' orbit is dwindling, it will take tens of millions of years to impact the surface).

None of which stops the twinkies trotting this obsolete theory out as though it were fact.

As a further note, I've just checked the book, and Shklovskii also cites a Russian writer of the time, F Zigel, to the effect that, since the Martian moons were not found by Herschel at the favourable opposition of 1862, but were found by Asaph Hall with a smaller telescope in 1877, they must have been placed in orbit during that period. But note that Shklovskii does not give this any real credence and refers to it as a 'bizarre' suggestion.

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Fin
Skep-ti-cult® member #488-28303-790

and they have been in orbit { about as is }
for less than 200 Million years
probably less than 100 mya
-----------------------------------
so any new Mac's
as i understand it
RELEASE DATE
===============
"FALL"
should be able to
do the reverse anamin
????????????????????????
aMen and all that
and you might find a
THIRD BODY

I can't find anyone citing any evidence for that. Have you any citations? I know that the captured asteroid theory has some dynamical problems. One idea that solves this is that Phobos and Deimos are residual fragments of a larger body that, in turn was fragmented by an impact.

And since Phobos has a remaining lifetime of ~50 million years, we might suppose that there were more small moons that passed inside the Roche Limit to be broken up into small fragments forming rings (otherwise it seems that we're rather lucky turning up just in the last few % of Phobos' lifetime). The fragments would over the years then decay into the atmosphere. Much like space debris from our satellites, they wouldn't, I imagine, leave much in the way of impact evidence (many of them may not even have reached the surface).

But it's kind of conjectural - the impact/capture could have happened 100m years ago or 2 billion or whatever, I'd have thought - depends on the size of the initial bodies and a lot of trajectory stuff.

Sorry, Hub - I don't quite get this bit.

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Fin
Skep-ti-cult® member #488-28303-790

Well, coincidence does happen... consider the angular size of the Earth's moon and the Sun (as seen from terra firma, that is). Not only is that unusual in the solar system, it's unusual in time: in an earier epoch the Moon was closer and therefore appeared larger; in the future it will be smaller and there will be no total solar eclipses (unless you count annular ones).

Stickney almost split Phobos apart. Although it's not clear when that happened, perhaps before Phobos was captured by Mars.

Actually, when Phobos hits Mars, it will make a huge crater. Not as big as Hellas, but very large (over 600 miles across, according to Boyce in "The Smithsonian Book of Mars").

I wonder how old the major impact basins on Mars are?