New Moon Formation Model

msheppard writes "This ariticle at Scientific American describes a new computer model describing the formation of the moon. "It is also strikingly similar to the first proposed impact theory 25 years ago, before computer simulations were available.""

Comments

Space.com article

[apsmith]

Space.com has another version with more graphics.

Except the article refers to a consensus reached 25 years ago, but I believe the actual "collision with a Mars-sized body" consensus came from the Kona, Hawaii meeting in 1984. So that's only 17 years... And basically this model is just an incremental improvement (will a big increment - 20,000 body simulation instead of 3,000) over previous simulations of the process. Still interesting though!

It does lend some

Re:General Agreement?

[dair]

Is this really the case? Last time I sat through astronomy in college they still seemed to make a lot of the "concurrent development" theory. Has that been shown wrong recently?

The problem is (or so I believe, never having taken an astronomy course in my life) that the Earth has a large amount of iron in its core - whereas the moon has almost no iron. If the Earth and moon coalesced out of the same matter at the same time, you'd expect them to have a similar composition.

The easiest way to explain the difference was to claim that the Earth was hit by another object which sloughed off part of the surface, leaving the core largely unchanged. The problem has been getting the timing and mass right: this simulation shows that it had to be about a Mars-sized object at a specific time - any bigger or smaller, or at a different time, and you need multiple collisions to obtain the Earth and moon as we see them today.

-dair (like I say, not an astronomer - just going by what I read in the paper this morning)

Re:An article about the model, but no grapics?

[StaticEngine]

Knock yourself out:

http://www.swri.org/press/impact.htm

Re:Why this model is important

[Alien54]

On a separate, but slightly related angle, there was a paper released a couple months back (see CNN Story) that came to the conclusion that something very weird happened in the Solar system about 65 million years ago. Studies of ocean sediment patterns reveal that the earth has been going through a 400,000 year climate cycle that is directly related to planetary distance. The problem is that these patterns change at about 65 million years ago. This is obviously related to the asteriod thast knocked of the dinosaurs.

Fringe groups have been looking at this and speculated that this is when the asteroids were formed, and when mars got its weird pattern of craters that cover only half the planet. You can download a nicely done 60 page document of this sort of thing (PDF - HTML). Unfortunately, the authors like to occasionally bring in things that are not relevant, so it sort of ruins the flavor, but it is not bad, and interesting reading, even if you do not take it seriously.

Which of course goes brings up all kinds of interesting speculations on just how common are planetary collisions in the first place.

- - -

White House Selected Vegetables Coffee Mug