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Name: J-MArc B.
Status: educator
Age: 50s
Location: N/A
Country: N/A
Date: 12/12/2004

How explain in a simple way that asteroids are potato shape (even Ceres the biggest one) and the Moon or Titan are spherical shape. Is it related to a liquid phase in their accretion ?

I think you would be better off talking about the possible histories of asteroids and moons.

Most objects "should" be spherical since, initially, all space objects start out as gaseous substances - and at that point must have the dynamics of a fluid in vacuum, surface tension and gravity being the two forces that would define the object's shape. But, after that, collisions become the next powerful shape-defining variable. You might even show pictures of different moons and show that some of them still show big impact - shape defining craters.

Greg (Roberto Gregorius)

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