[meteorite-list] Catch A Comet?

From: Richard Kowalski <*damoclid_at_meteoritecentral.com*> Date: Mon, 14 Sep 2009 12:47:53 -0700 (PDT) Message-ID: <691819.4550.qm_at_web33902.mail.mud.yahoo.com> · damoclid_at_meteoritecentral.com

--
Richard Kowalski
http://fullmoonphotography.net
IMCA #1081
--- On Mon, 9/14/09, Mexicodoug <mexicodoug at aim.com> wrote:
> From: Mexicodoug <mexicodoug at aim.com>
> Subject: Re: [meteorite-list] Catch A Comet?
> To: damoclid at yahoo.com, meteorite-list at meteoritecentral.com, sterling_k_webb at sbcglobal.net
> Date: Monday, September 14, 2009, 12:33 PM
> Cheers Richard, Sterling, List,
> 
> "Impossible" and its near variants seem less and less
> meaningful these days... IMO Sterling's original question is
> a good one better understood by the relative probabilities
> of a comet impact on Earth vs. the comet going into orbit,
> rather than just considering the difficult physics. Is it
> likely to have happened at least once in Earth's billions of
> years of history? Anyway, when Sterling asked "what it would
> take", I think he was already considering the improbability
> of such an event during the fleeting human experience, and
> such a possibility would be nice to contemplate. While it
> may not have much scientific interest in some circles, I am
> just imagining the celestial show Earth would be treated to
> every night for some time as beautiful meteors poured upon
> Earth without mercy in such a hypothetical event, and what
> breathtaking interactions the Earths Van Allen Belt would
> create ... making tea time under the stars a picturesque
> fantasy painting ...
> 
> What of he case of a small comet had an opposition near
> earth during a perihelion, what kind of minimum energy are
> we talking about to playing mad scientist and nudge it in
> orbit (not impacting). That's a question several list
> members could eat for breakfast.
> 
> Then there is the other mostly unrelated greatly
> hypothetical question about probabilities for some reason
> this reminded me of. What sort of ratio of Lunar glass
> meteorites (vs. stones, melts and the rest of the geological
> zoo) is reasonable to expect to arrive at Earth from what we
> know of Lunar impacts? Would a glass meteorite devoid of
> volatiles shatter into little bits upon Earth entry - better
> stated, what is the probability of a Lunar tektite's
> meteoric passage to Terra Firma?
> 
> Best wishes,
> Doug
> 
> 
> 
> 
> 
> 
> 
> -----Original Message-----
> From: Richard Kowalski <damoclid at yahoo.com>
> To: Meteorite List <meteorite-list at meteoritecentral.com>;
> Sterling K. Webb <sterling_k_webb at sbcglobal.net>
> Sent: Mon, Sep 14, 2009 12:59 pm
> Subject: Re: [meteorite-list] Catch A Comet?
> 
> 
> 
> Sterling,
> it is all but impossible for the earth to acquire a "comet
> moon" due to the
> orbital energies involved. Earth's gravity is much too
> small for this to occur.
> An asteroidal moon is much more probable and has actually
> happened. You may
> remember a few years ago when my colleague, Eric
> Christensen discovered 6R10DB9,
> which was Earth's first know "Second Moon". albeit a
> temporary one.
> 
> A good article and orbital diagram can be found on the Sky
> & Telescope site
> here:
> 
> http://www.skyandtelescope.com/news/home/7067527.html
> 
> Note Al Harris' comment about it being called a true
> "satellite".
> 
> 
> --
> Richard Kowalski
> http://fullmoonphotography.net
> IMCA #1081
> 
> 
> --- On Mon, 9/14/09, Sterling K. Webb <sterling_k_webb at sbcglobal.net>
> wrote:
> 
> > From: Sterling K. Webb <sterling_k_webb at sbcglobal.net>
> > Subject: [meteorite-list] Catch A Comet?
> > To: "Meteorite List" <meteorite-list at meteoritecentral.com>
> > Date: Monday, September 14, 2009, 10:00 AM
> > It seems that not only do comets
> > impact Jupiter,
> > they may also become moons, temporary or
> > permanent, of the planet.
> > 
> > Wonder what it would take to get a "comet moon"
> > for the Earth?
> > 
> > Sterling K. Webb
> >
> -------------------------------------------------------------------
> > 
> > http://www.space.com/scienceastronomy/090914-jupiter-comet.html
> > Gotcha! Jupiter Turned Comet into a Moon By SPACE.com
> > Staff
> > 
> > Jupiter already has an abundance of moons, but from
> 1949 to
> > 1961 it had another, temporary satellite in the form
> of a
> > comet trapped in the gas giant's gravitational grip.
> > 
> > Comet 147P/Kushida-Muramatsu was captured as a
> temporary
> > moon of Jupiter in the mid-20th century and remained
> trapped
> > in an irregular orbit for about twelve years,
> astronomers
> > announced today.
> > 
> > There are only a handful of known comets where this
> > phenomenon of temporary satellite capture has occurred
> and
> > the capture duration in the case of Kushida-Muramatsu
> is the
> > third longest.
> > 
> > The discovery was presented today at the European
> Planetary
> > Science Congress in Potsdam by David Asher of Armagh
> > Observatory in Northern Ireland.
> > 
> > An international team led by Katsuhito Ohtsuka of the
> Tokyo
> > Meteor Network modeled the trajectories of 18
> "quasi-Hilda
> > comets," objects with the potential to go through a
> > temporary satellite capture by Jupiter that results in
> them
> > either leaving or joining the "Hilda" group of objects
> in
> > the asteroid belt. Most of the cases of temporary
> capture
> > were flybys, where the comets did not complete a full
> > orbit.
> > 
> > But Kushida-Muramatsu was different: The team used
> recent
> > observations tracking the comet over nine years to
> calculate
> > hundreds of possible orbital paths for it over the
> previous
> > century. In all scenarios, Kushida-Muramatsu completed
> two
> > full revolutions of Jupiter, making it only the fifth
> > captured orbiter to be identified.
> > 
> > "Our results demonstrate some of the routes taken by
> > cometary bodies through interplanetary space that can
> allow
> > them either to enter or to escape situations where
> they are
> > in orbit around the planet Jupiter," Asher said.
> > 
> > Asteroids and comets can sometimes be distorted or
> > fragmented by tidal effects induced by the
> gravitational
> > field of a capturing planet, or may even impact with
> the
> > planet. The most famous victim of both these effects
> was
> > comet D/1993 F2 (Shoemaker-Levy 9), which was torn
> apart on
> > passing close to Jupiter and whose fragments then
> collided
> > with that planet in 1994. Previous computational
> studies
> > have shown that Shoemaker-Levy 9 may well have been a
> > quasi-Hilda comet before its capture by Jupiter.
> > 
> > "Fortunately for us Jupiter, as the most massive
> planet
> > with the greatest gravity, sucks objects towards it
> more
> > readily than other planets and we expect to observe
> large
> > impacts there more often than on Earth. Comet
> > Kushida-Muramatsu has escaped from the giant planet
> and will
> > avoid the fate of Shoemaker-Levy 9 for the
> foreseeable
> > future," Asher said.
> > 
> > The object that impacted with Jupiter this July,
> causing
> > the new dark spot discovered by Australian amateur
> > astronomer Anthony Wesley, may also have been a member
> of
> > this class, even if it did not suffer tidal disruption
> like
> > Shoemaker-Levy.
> > 
> > "Our work has become very topical again with the
> discovery
> > this July of an expanding debris plume, created by the
> dust
> > from the colliding object, which is the evident
> signature of
> > an impact. The results of our study suggest that
> impacts on
> > Jupiter and temporary satellite capture events may
> happen
> > more frequently than we previously expected," Asher
> said.
> > 
> > The team has also confirmed a future moon of Jupiter.
> Comet
> > 111P/Helin-Roman-Crockett, which has already orbited
> Jupiter
> > three times between 1967 and 1985, is due to complete
> six
> > laps of the giant planet between 2068 and 2086.
> > 
> > 
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> 
> 
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