[meteorite-list] Lunar capture theory
From: Howard Wu <freewu2000_at_meteoritecentral.com>
Date: Thu Apr 22 10:21:03 2004 Message-ID: <20030711233522.54458.qmail_at_web9307.mail.yahoo.com> --0-1559473940-1057966522=:53502 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit While this sounds good. It is very hard for two bodies to capture each other due to laws of celestial mechanic of Newton. Conservation of energy requires a third body to take away excess energy from the system. This is a simplified explaination before you real physicists jump in. Howard Wu Tom aka James Knudson <knudson911_at_frontiernet.net> wrote: Hello Robert and list, My understanding of planet formation in a nutshell is that debris orbiting the Sun gradually merged and formed planets. Right? Why couldn't two bodies have formed from the same debris in the same orbit and orbiting around the sun together in the same direction and the same orbit, Gradually the Moon slowly caught up with the earth and got caught up in the earths gravity? Or the earth came up behind the Moon and captured it? Thanks, Tom Peregrineflier The proudest member of the IMCA 6168 ----- Original Message ----- From: Matson, Robert To: meteorite-list Sent: Friday, July 11, 2003 1:01 PM Subject: [meteorite-list] Lunar capture theory > Tom wrote: > > > I do not believe the moon was made by a asteroid impact on the > > earth. > > What, specifically, about this theory bothers you? > > > I would first stand by the theory that it was caught up in our > > gravity. > > While this is a ~possible~ scenario, you have to understand how > extremely unlikely graceful capture is compared to impact. > The capture idea also has a difficult time explaining why the > Moon doesn't have a normal-sized core for a body of its size, > which the impact theory explains nicely. Finally, why the > oxygen-isotope similarity of earth and the Moon if the two > bodies formed in different parts of the solar system? > > Prior to the Apollo sample return missions (and the discovery > of our beloved lunar meteorites), the capture theory at least > had some wobbly legs to stand on. But O-isotope analysis of > the moon rocks knocked one leg out, and the other leg was swept > away by Lunar Prospector's confirmation that the moon's core > comprises less than 3% of the moon's mass. > > --Rob > > > > ______________________________________________ > Meteorite-list mailing list > Meteorite-list_at_meteoritecentral.com > http://www.pairlist.net/mailman/listinfo/meteorite-list > ______________________________________________ Meteorite-list mailing list Meteorite-list_at_meteoritecentral.com http://www.pairlist.net/mailman/listinfo/meteorite-list --------------------------------- Want to chat instantly with your online friends? Get the FREE Yahoo!Messenger --0-1559473940-1057966522=:53502 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit <DIV>While this sounds good. It is very hard for two bodies to capture each other due to laws of celestial mechanic of Newton. Conservation of energy requires a third body to take away excess energy from the system. This is a simplified explaination before you real physicists jump in.</DIV> <DIV> </DIV> <DIV>Howard Wu<BR><BR><B><I>Tom aka James Knudson <knudson911_at_frontiernet.net></I></B> wrote:</DIV> <DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid; WIDTH: 100%">Hello Robert and list, My understanding of planet formation in a nutshell is<BR>that debris orbiting the Sun gradually merged and formed planets. Right?<BR>Why couldn't two bodies have formed from the same debris in the same<BR>orbit and orbiting around the sun together in the same direction and the<BR>same orbit, Gradually the Moon slowly caught up with the earth and got<BR>caught up in the earths gravity? Or the earth came up behind the Moon and<BR>captured it?<BR><BR>Thanks, Tom<BR>Peregrineflier<BR>The proudest member of the IMCA 6168<BR>----- Original Message -----<BR>From: Matson, Robert <ROBERT.D.MATSON_at_SAIC.COM><BR>To: meteorite-list <METEORITE-LIST@METEORITECENTRAL.COM><BR>Sent: Friday, July 11, 2003 1:01 PM<BR>Subject: [meteorite-list] Lunar capture theory<BR><BR><BR>> Tom wrote:<BR>><BR>> > I do not believe the moon was made by a asteroid impact on the<BR>> > earth.<BR>><BR>> What, specifically, about this theory bothers you?<BR>><BR>> > I would first stand by the theory that it was caught up in our<BR>> > gravity.<BR>><BR>> While this is a ~possible~ scenario, you have to understand how<BR>> extremely unlikely graceful capture is compared to impact.<BR>> The capture idea also has a difficult time explaining why the<BR>> Moon doesn't have a normal-sized core for a body of its size,<BR>> which the impact theory explains nicely. Finally, why the<BR>> oxygen-isotope similarity of earth and the Moon if the two<BR>> bodies formed in different parts of the solar system?<BR>><BR>> Prior to the Apollo sample return missions (and the discovery<BR>> of our beloved lunar meteorites), the capture theory at least<BR>> had some wobbly legs to stand on. But O-isotope analysis of<BR>> the moon rocks knocked one leg out, and the other leg was swept<BR>> away by Lunar Prospector's confirmation that the moon's core<BR>> comprises less than 3% of the moon's mass.<BR>><BR>> --Rob<BR>><BR>><BR>><BR>> ______________________________________________<BR>> Meteorite-list mailing list<BR>> Meteorite-list_at_meteoritecentral.com<BR>> http://www.pairlist.net/mailman/listinfo/meteorite-list<BR>><BR><BR><BR><BR>______________________________________________<BR>Meteorite-list mailing list<BR>Meteorite-list@meteoritecentral.com<BR>http://www.pairlist.net/mailman/listinfo/meteorite-list</BLOCKQUOTE></DIV><p><hr size=1><font face="Arial" size="2">Want to chat instantly with your online friends? <a href="http://uk.rd.yahoo.com/mail/tagline_messenger/*http://uk.messenger.yahoo.com/"><b>Get the FREE Yahoo! Messenger</b></a></font> --0-1559473940-1057966522=:53502-- Received on Fri 11 Jul 2003 07:35:22 PM PDT |
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