I've seen mention of the possibility that J002E3 may impact the Moon at some point; one source quoted the odds of that happening in 2003 as high as 20%. If that occurs (on this encounter or any future one) would the observation of the impact provide any useful scientific information? I know the Apollo lunar seismometers were turned off long ago in a budget-cutting move (that darned human exploration is so expensive!) but would observation of the impact reveal something about the composition of the lunar subsurface, such as the presence of volatiles? I know that was unsuccessfully attempted with Lunar Prospector ...
- John from Cambridge -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Bruce Moomaw Sent: Thursday, September 12, 2002 2:02 PM To: Europa Icepick Subject: Re: New 'moon' found around Earth ----- Original Message ----- From: "adam ." <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, September 12, 2002 9:47 AM Subject: RE: BBC E-mail: New 'moon' found around Earth > > the dictionary also says 'minor planet revolves around sun' and since you > stated that Cruithne appears to cross the orbit of venus and mars too but > did not mention anything about it relvolving around the sun i would thus > assume that it is not a minor planet, and i never said that Cruithne should > be called a moon, but it sure shouldn't be called a minor planet. I like > Moonlet. Actually, Cruithne is by no stretch of the imagination a moon of Earth -- it's just a Sun-orbiting asteroid which has been nudged by repeated gravitational tugs from Earth into a "resonant" orbit; one whose timing is synchronized with that of Earth (although, as mentioned, its perihelion is far closer to the Sun than Earth's and its aphelion is much farther away). You could use the same reasoning to say that Pluto is a "moon" of Neptune -- or that Io is a "moon" of Europa! In short, all those stories about Cruithne as a "moon" of Earth are just further displays of the tendency of newpapers to play tabloid whenever they're dealing with even moderately complex scientific issues that can be misrepresented to the general public in a sensationalistic way. But this latest thingie really is orbiting Earth. I agree that it's probably the S-4B stage from Apollo 12, which had a slight malfunction during the deflection maneuver intended to slingshot it past the Moon and into solar orbit (where the S-4Bs for Apollos 8 through 11 ended up). It's probably too big to be the final stage from any of the Soviet lunar and planetary probe boosters (although some of them were pretty big). It would be worthwhile trying to make more observations of its shape and spectral chracteristics, though, on the off-chance that it really is a temporarily captured natural asteroid. By the way, the problem of officially labeling "moon" is even more maddening -- and ultimately arbitrary -- than the problem of whether Pluto counts as a planet. Does every single ring particle of Saturn deserve to be called a "moon" and given a name? If not, then we're going to have to set some kind of size cutoff for the label (just as we have to do with planets). Karkoschka's abstract at the upcoming DPS meeting extrapolates that there are probably about 100 irregular moons of Jupiter bigger than 1 km diameter -- God knows how many smaller ones there are. And, yes, it is possible for a solar-orbiting object to be temporarily captured into orbit around a planet and then later depart again -- this happens regularly with Jupiter and comets, none of which are ever labeled as its "moons". Shoemaker-Levy 9 was one such comet which suffered the relatively rare fate of eventually crashing into the planet instead. Final note: Michael Swanwick recently wrote an SF story in which it IS decided that every single ring particle of Saturn is a moon and must be named, and so some poor government bureaucrat is assigned to spend his entire life doing only that. Upon discovering from the photos of the particles automatically sent to him from Saturn orbiters that one of the particles is actually an ancient alien spacecraft -- and knowing that no one will ever, ever read through his list after he's finally done -- he names it "Youshouldhavepaidmemore" and then makes no further mention of it to anyone. == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
