Watching Family Channel last night they had previews of a coming show/movie “3 moons over…” well some town.
From the previews I gather the “plot” surrounds people at the “End of The World”. Obviously the moon was hit by a large planetoid/comet which causes the moon to shatter into three large chunks. One about half the moon, the other two about ¼ each with debris extending around about the area. The previews show the moon hanging in the sky as three large chunks – we can tell it is our moon because the mares (seas) which make up the “man on the moon” can still be seen.
The plot suggests that one (possible more) large chunks are on a decaying orbit (heading toward earth) thus folk are acting “crazy” as the end draws nigh.
This caused me to wonder a few things:
1. If the moon is hit by an object large enough and powerful enough to cause it to split into three large fragments (with lots of debris) wouldn’t the three fragments continue to move away from each other? Wouldn’t the local escape velocity have already been surpassed to allow a significant (naked eye view) of space in between the chunks thus the pieces would continue to spread further apart?
2. OR is it possible that these three chunks could be “exploded” outward a ‘short” distance and then local gravity (of all of the debris) cause the moon to fall back toward a constant center of gravity?
3. In the previews the interior of the moon can be seen as the three pieces hang in the sky – it, like the surface, is grey (dead). A. Wouldn’t a sufficiently large enough impact event lead to a lot of heat energy thus lead to melting? B. Doesn’t the moon have a mantel/core of molten material (granted much smaller and with a thicker crust)?
4. In the previews one can still see “the man in the moon” the craters/mares of the face that we all know. Wouldn’t an impact event pretty much disrupt the whole surface with moon-quakes?
5. Is it even possible for an impact event to shatter the moon into three large chunks? Wouldn’t such an event lead to a field of rubble. I assume that the amount of energy needed would literally shatter the moon into billions of little pieces, sending a large fraction into new orbits, causing the moon to spread out into a ring around the earth.
6. If such an event took place, other than moon rocks falling on our heads, wouldn’t there be significant changes on the tides on the earth to cause changes in weather, possibly earthquakes? If even a ¼ of the moon was on its way toward earth (decayin orbit) would the gravity affects be felt as it neared?
Posts: 4020 | Location: Leaving land, heading for the ocean | Registered: 06-03-02
I'll attempt to answer some of these: 1,2) Without data, it is impossible for me to say definitively whether or not the chunks would fly apart (having not seen the ad, which sounds really cool). Seems to me that anything imparting enough energy to crack the moon like that would also impart a great deal of momentum, possibly knocking the moon out of its orbit altogether, which I believe is most likely. 3) The surface of the moon surely would have been vaporized in any impact with such energy. The moon's core is metallic, though not molten. No magnetic field surrounds the moon, these fields are a result of a spinning metallic molten core. The core of the moon has frozen sooner than the Earth's due to smaller size. 4) The mountains and valleys on the moon would melt away as the surface essentially turned into a lava flow. When the rock froze, any familiar features of the moon would be non-existant. 5) You are right. The impact that created our moon blew the Earth almost completely apart, and left us with a ring. The ring became our moon, and how different does the moon look from the Earth? 6) The answer to this question depends on how the show's creators want to explain the destruction of the moon. If somehow the moon just "cracks" and drifts apart somewhat, then the effects would be minimal here. In fact, the moon chunks would be in more peril than the Earth. Of course, impacts are bad and have the obvious consequences. Bruce Willis could save us!
