The Daily Flash: Eco, Space, Science (17/2)
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Gravity Disturbances on the Dark Side Of The Moon-Do They Prove the "Giant Impact" Theory

6a00d8341bf7f753ef00e5508aa34988338 It sounds like a Buck Rogers plot, or a rave remix of Pink Floyd, but it's the very latest news from our very nearest astronomical neighbor.  The Japanese SELENE mission (SELenological and ENgineering Explorer) has probed the far side of the moon in unprecedented detail.  The effects will be felt in lunar research for years, but the first headline you'll hear about is the negative gravity disturbance rings.

Now that definitely sounds like something Electra, Queen of the Lunar Amazon Women, would apply to Buck before being seduced.  It's important not to get overexcited - here "negative anomaly" simply means that there's less gravity than average, not that there are anti-gravity sites hidden where we couldn't see them until now.  These rings surround small zones of positive gravity anomalies, unlike anything we've seen on the near side, and offer brand new information on the formation of the moon.

It seems that the two sides of the moon have evolved differently since their formation, with the far side forming at cooler temperatures and remaining stiffer while the Earth side has been modified at higher temperatures and for longer.  This information is extremely important for theories on the formation of the moon, of which the current favorite is the "Giant Impact" hypothesis aka "If Michael Bay and Joel Schumacher were hired to co-direct God."

The Giant Impact idea is that four and a half billion years ago a planet the size of Mars rammed Earth, kicking enough debris into orbit to accrete into an entirely new body, Mr Moon.  You'd think something like that would leave evidence more visible than gravitational mapping of the dark side of a satellite, but don't worry: we'll get there.

Luke McKinney.

Science, reference 10.1126/science.1170655

Comments

I think it's the precision of the Kaguya data, and the density of the datapoints, that is the news here, and not ringed Mascons. The ringed Mascon was mapped of Orientalis quite some time ago, as has, obviously, the vast differences between the Near and Far hemispheres of the Moon. In the situation of Kaguya, the news is the accuracy vs. the ULCN 2005 data from USGS. I don't think any of this new data addresses the Impact theory of lunar origins at all. It may, however, bring us closer to proving or disproving the Megabasin Impact theory, which holds that, prior to the Basin-forming impact that created the massive South-Pole Aitken basin, there may have been an even larger event, the so-called Mega-impact that has been centered near Ross crater in the northwestern area of Mare Tranquillitatis, and whose outer ring and ejecta led to the creation of the Far Side lunar highlands, and may or may not be the solution to the mystery of the event that created Procellarum. The data may go a long way in solving the timetable of any Grand Bombardment in the early Solar System

(Easy to see why they would call it a Megabasin. But such an event may have led to the creation of a hemispheric discontinuity not unlike what is seen on Mars. The SPA basin arrived later.)

One reason for Luna always turning her same face toward Earth is the difference internally in the moon's construction, with the more massive part on the near side and the "lighter" half on the far side.

This also kind of supports the idea that Luna could have originated as an entirely separate entity formed by collision instead of accretion, and that idea in turn could make the evolution of life on Earth a possibility that would not have existed otherwise.

Certainly Luna is an anomaly among the many, many satellites that orbit other planets, not because of her actual size but because of her comparatively large volume and mass relative to her primary, Earth. The rest of the "moons" in the solar system are all relatively tiny in comparison to the planets they are in orbit around.

Nothing is perfect in this universe....I would think that also Terra (Earth) should have some 'gravity-anomalies'...that means different gravity force from one area to another...does this appear to be a 'normal ' fact ??? YES.

The 'big impact theory'...seems viable...the famous 'Occam razor' principle....tends to apply.

However about gavity anomalies....it should also be considered that in a somewhat early Luna(moon) somehow liquid inside in its infancy...the iron was definitely attracted by the side facing earth.....and the gravity center of Luna is Not so perfect ...and it is a bit out of the center of the volume.......

Somehow is nice guessing around...True ??

Regards to Luna...

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