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Unmanned Spaceflight.com _ Lunar Exploration _ The lunar fossil bulge

Posted by: AlexBlackwell Aug 2 2006, 10:11 PM

This http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2429.pdf by Garrick-Bethell and Zuber, which was presented earlier this year at the http://www.lpi.usra.edu/meetings/lpsc2006/, should be included in your overnight reading.

Posted by: AlexBlackwell Aug 3 2006, 06:56 PM

Did everyone do their homework? biggrin.gif

The Garrick-Bethell et al. paper ("Evidence for a Past High-Eccentricity Lunar Orbit") and the accompanying Perspectives piece by Kimmo Innanen ("Solving Laplace's Lunar Puzzle") are being published in the http://www.sciencemag.org/content/vol313/issue5787/index.dtl.

See also:

http://www.space.com/scienceastronomy/060803_moon_shape.html
By Sara Goudarzi
Staff Writer, Space.com
posted: 03 August 2006
02:10 pm ET

Posted by: AlexBlackwell Aug 8 2006, 01:29 AM

Some related press articles:

http://www.cosmosmagazine.com/node/515
by Marie Theresa Bray
Cosmos Online
Friday, 4 August 2006

http://www.nytimes.com/2006/08/08/science/space/08moon.html
By KENNETH CHANG
The New York Times
August 8, 2006

Posted by: Myran Aug 9 2006, 07:14 PM

Thank you for the heads up, and that explanation do indeed sound plausible.
To me it seems that this theory also go hand in hand with the impact scenario for the Moons formation. Since the eccentric orbit would be a more likely result from such one impact.

Posted by: AlexBlackwell Aug 9 2006, 10:03 PM

QUOTE (Myran @ Aug 9 2006, 09:14 AM) *
Thank you for the heads up, and that explanation do indeed sound plausible.
To me it seems that this theory also go hand in hand with the impact scenario for the Moons formation. Since the eccentric orbit would be a more likely result from such one impact.

Great minds think alike, I guess. biggrin.gif

Here's an excerpt (references omitted) from http://www.physics.yorku.ca/faculty_p/p.innanen.htm's accompanying Perspectives piece ("http://www.sciencemag.org/cgi/content/short/313/5787/622") in the same issue:

QUOTE
In the work of Garrick-Bethell et al., the central issue is the Moon's own nonspherical shape, which, together with its orbit, lead the authors to an interesting conclusion about its past history: Its orbit around Earth in the distant past must have been much closer and also more eccentric than it is now. In fact, their optimum solutions locate the young Moon at a time 100 to 200 million years after its formation, when it was at a distance of some 24 to 27 Earth radii. At this time it would have passed through the 3:2 spin-orbit resonance, reminiscent of the present-day behavior of the planet Mercury, which rotates three times about its own axis for every two revolutions about the Sun. They show that the distance and eccentricity at this time would have been optimal for the bulge to "freeze" into the solidifying Moon, a fossil bulge we observe to this day. These results appear to dovetail in a reasonable way with the most viable contemporary theory of the Moon's own origin through a giant impact of a Mars-like object with Earth, from which debris the primordial Moon formed at some 4 Earth radii.

Posted by: RNeuhaus Aug 10 2006, 04:26 PM

About the Moon bugle, I would like to know what part of Moon has bugle. As I have observed my Moon Near Side Map and have found that the North and South regions has higher altitude average than in the middle latitudes. The Mars (Marias) are in the lower level of surface. I haven't seen the Moon Far Side. I suppose that the lowest point of Moon is at the Atkinson Crater which is the biggest impact crater of the solar system.

Rodolfo

Posted by: AlexBlackwell Sep 1 2006, 11:29 PM

QUOTE (AlexBlackwell @ Aug 3 2006, 08:56 AM) *
The Garrick-Bethell et al. paper ("Evidence for a Past High-Eccentricity Lunar Orbit") and the accompanying Perspectives piece by Kimmo Innanen ("Solving Laplace's Lunar Puzzle") are being published in the http://www.sciencemag.org/content/vol313/issue5787/index.dtl.

For those without access to Science, one of the paper's co-authors, Maria Zuber, is offering a reprint (http://www-geodyn.mit.edu/garrickbethell.moon.science06.pdf) via her http://www-geodyn.mit.edu/mtzpub.html.

Posted by: stevesliva Aug 4 2011, 02:28 AM

Bump to an old old thread because it has some older theories about the lunar farside. I was curious what past thinking was after today's news.

New theory published today in Nature:
http://www.nature.com/news/2011/110803/full/news.2011.456.html

Somehow Gawker got a better image, though:
http://gawker.com/5827556/we-used-to-have-another-moon-until-our-moon-murdered-it

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