Exploding Planets




Name: Gregory R.
Status: other
Grade: K-3
Location: NJ

Question: Did any planet ever blow up?
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Dear Gregory,

Planets do not blow up.  About 3.9 billion years ago a Mars-sized protoplanet 
(you could call it  young planet) collided with Earth, ripping off its crust.  
For about a year after the collision there was a thick ring about the Earth.  
The particles, both from the Earth and the other planet, joined together 
within a year to form the Moon.    Jupiter must have had this experience 
many times with other protoplanets.  But a planet just blowing up?  I doubt 
it.

David H. Levy
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Gregory,
 
That would depend on what you mean by blow up. Research indicate that in the 
very early history of our solar system, there was a planet orbiting where 
Earth is now (let's call this planet: proto-Earth). Near this proto-Earth was 
another planet (let's call this planet: proto-Moon). Because proto-Earth and 
proto-Moon had orbits that brought them very close to each other, the two 
planets collided and smashed into each other. The force of this collision was 
so strong that it blew up both planets. However, since the blown up bits of both 
planets were still close to each other, the planets reformed into what is now 
Earth and the moon. The reason we know this is that the core of the Moon is 
very much like that of Earth and that is unusual. Also, unlike most moons that 
get closer to the planet that it is orbiting, our moon is getting farther away - 
which tells us that it used to be very close to the Earth.
 
Greg (Roberto Gregorius)
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