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Showing posts from November, 2013

Black Holes

How about a bit of science?
Everyone's heard about Black Holes, but what the heck are they?
First, a little background.  If you throw a ball up from the Earth, it will slow down and eventually fall back to the Earth.  No matter how fast you throw it up, it will always come back down.  Suppose you used a nice, fancy machine to throw it up faster than you can.  Will it always come back down?
Happily, the answer is no.  If you have a very powerful machine, (and we don't have one yet that can do this), that can throw the ball so that when it leaves the machine it is traveling at around 7 miles per second, the ball will go up and never come back down.  It will indeed slow down continuously, but not enough to head back toward Earth.  This speed that an object needs to leave a planet or any other mass, is called its escape velocity.  For instance the Moon has an escape velocity of about 1.5 miles per second.
You can probably guess that the more massive and dense the object, the higher it…