10-January-2009, 07:09 AM
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Order of Kilopi
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Join Date: Jun 2004
Location: Lugano, Switzerland
Posts: 3,734
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Quote:
Well, the most massive black hole one can possibly make is if all of the energy from the collision goes into making that black hole. Let’s assume that one million of these collisions occur, and all of them make black holes, which can then merge together (again, this is incredibly, unrealistically optimistic, but let’s go for it). For the maximum collision energy at CERN (14 TeV), E = mc2 tells us that the end black hole would have a mass of 2.5 x 10-14 grams. That’s 25 femtograms, which means this black hole would have an event horizon trillions upon trillions of times smaller than the size of a proton.
Now, maybe you think it’s reasonable that this black hole, if it’s created at rest, would simply fall into the Earth, consuming all the particles in its path. Let’s assume it could do this, in fact, and let’s find out how much mass it would eat.
As it falls into the Earth, it starts running into protons, and let’s assume whenever it runs into one, it gobbles it up. By time it gets to the center of the earth , it will have eaten about 10-16 grams of matter, which means it can grow by about 0.4% in the 30 minutes or so it takes to get to the center of the Earth. It will then head towards the other side, gobbling up that matter until it stops in the upper mantle, and then heads back towards the center of the Earth. It should do this over and over, each time gobbling up more matter (at a constant rate of about 4 x 10-16 grams per hour), each time getting farther and farther away from the Earth’s surface, never to quite reach it again.
At this rate, it would still take three billion years for the black hole to suck in even one gram of matter! So the chances of this happening?
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source: http://startswithabang.com/?p=878
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