[meteorite-list] Stardust Flyby Images of Comet Wild 2

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From: Howard Wu <freewu2000_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:00 2004
Message-ID: <20040108183313.8255.qmail_at_web60005.mail.yahoo.com>

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Primer follow up: Theory is that a shell of comets surround the solar system in the Oort cloud past Neptune, and then ocassionally one is disturb into falling into the inner solar system. There was a hypothesis proposed that there was a dark companion star to the sun with an ecentric orbit of 26 million years that rains down comets periodically causing episodic extinctions. Look up "Nemesis" for more info.

Howard

Ron Baalke <baalke_at_zagami.jpl.nasa.gov> wrote:
>
> I know I should research this myself but I hope I can get a relatively brief
> answer upon which I can look further into this question if deemed worthwhile.
> How does a small object like a comet, especially, travel for billions of
> years constantly venting and releasing matter continue to exist? Why doesn't
> it dissipate into virtual nothingness?
>

Some comets have been observed to split apart. SOHO has observed many of the sun grazers
to fall apart entirely. But not all comets will just disappear. They'll eventually
lose all of their volatiles and become a burnt-out comet. At that point they will
resemble an asteroid. There are a few asteroids that we suspect to be former comets -
they are in very elongated orbits, but have not formed a tail.

Comet Wild 2 is considered to be a 'fresh' comet. It has been in the inner
solar system for only about 30 years. Prior to 1974, Comet Wild 2 was in a distant orbit
that crossed the orbits of Jupiter and Uranus. A close flyby of Jupiter in September 1974
radically perturbed its orbit closer to the Sun. Its orbits now
crosses the orbit of Mars at perihelion and the orbit at Jupiter at aphelion.
Being closer to the Sun means it now a much brighter object, and Paul Wild
discovered the comet in 1978.

Ron Baalke

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<DIV>Primer follow up: Theory is that a shell of comets surround the solar system in the Oort cloud past Neptune, and then ocassionally one is disturb into falling into the inner solar system. There was a hypothesis proposed that there was a dark companion star to the sun with an ecentric orbit of 26 million years that rains down comets periodically causing episodic extinctions. Look up "Nemesis" for more info.</DIV>
<DIV> </DIV>
<DIV>Howard Ron Baalke <baalke_at_zagami.jpl.nasa.gov> wrote:</DIV>
<BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">> > I know I should research this myself but I hope I can get a relatively brief > answer upon which I can look further into this question if deemed worthwhile. > How does a small object like a comet, especially, travel for billions of > years constantly venting and releasing matter continue to exist? Why doesn't > it dissipate into virtual nothingness? > Some comets have been observed to split apart. SOHO has observed many of the sun grazers to fall apart entirely. But not all comets will just disappear. They'll eventually lose all of their volatiles and become a burnt-out comet. At that point they will resemble an asteroid. There are a few asteroids that we suspect to be former comets - they are in very elongated orbits, but have not formed a tail. Comet Wild 2 is considered to be a 'fresh' comet. It has been in
the inner solar system for only about 30 years. Prior to 1974, Comet Wild 2 was in a distant orbit that crossed the orbits of Jupiter and Uranus. A close flyby of Jupiter in September 1974 radically perturbed its orbit closer to the Sun. Its orbits now crosses the orbit of Mars at perihelion and the orbit at Jupiter at aphelion. Being closer to the Sun means it now a much brighter object, and Paul Wild discovered the comet in 1978. Ron Baalke ______________________________________________ Meteorite-list mailing list Meteorite-list_at_meteoritecentral.com http://www.pairlist.net/mailman/listinfo/meteorite-list</BLOCKQUOTE><hr size=1> <a href="http://uk.rd.yahoo.com/mail/tagline_messenger/*http://uk.messenger.yahoo.com">
Yahoo! Messenger</a> - Communicate instantly..."Ping" your friends
today! <a href="http://uk.rd.yahoo.com/mail/tagline_messenger/*http://uk.messenger.yahoo.com/download/index.html">Download Messenger Now</a>
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Received on Thu 08 Jan 2004 01:33:13 PM PST

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