[meteorite-list] Catch A Comet?

[Richard Kowalski]

As I said in a previous message, wait for the qualifier!

Thanks Doug.


--
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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