Friday, September 12, 2008

Why we shouldn't worry about the Earth being swallowed up by a Black Hole created by the Large Hadron Collider

I don't know if you were worried about this possibility, but my Mom has been. Fortunately, according to Brian Greene (and the rest of the physics community), you shouldn't be:

"Now for the possibility that's generated the fuss.

Recent work in string theory has suggested that the collider might produce black holes, providing physicists with a spectacular opportunity to study them in a laboratory.

The common conception is that black holes are fantastically massive astrophysical bodies with enormous gravitational fields. But in reality, a black hole can have any mass. Take an orange and squeeze it to a sufficiently small size (about a billionth of a billionth of a billionth of a meter across) and you'd have a black hole — with the mass of an orange.

Physicists have realized that the collider's proton-proton collisions might momentarily pack so much energy into such a small volume that exceedingly tiny black holes may form — black holes even lighter than the one theoretically created by the orange, but black holes nevertheless.

Why might one worry that this would be a problem? Because black holes have a reputation for rapacity. If a black hole is produced under Geneva, might it swallow Switzerland and continue on a ravenous rampage until the earth is devoured?

It's a reasonable question with a definite answer: no.

Work that made Stephen Hawking famous establishes that tiny black holes would disintegrate in a minuscule fraction of a second, long enough for physicists to reap the benefits of having produced them, but short enough to avoid their wreacking any havoc.

Even so, some have worried further that maybe Dr. Hawking was wrong and such black holes don't disintegrate. Are we willing to bet the fate of the planet on an untested insight? And that question takes us to the crux of the matter: the collisions at the Large Hadron Collider have never before occurred under laboratory settings, but they've been taking place throughout the universe — even here on earth — for billions of years.

Cosmic rays — particles wafting through space — constantly rain down on the earth, the other planets and the wealth of stars scattered throughout the galaxy, with energies far in excess of those attainable by the Large Hadron Collider. And since these more powerful collisions haven't resulted in astrophysical calamities, the collider's comparatively tame collisions most assuredly won't either."

So if you weren't worried about this, don't start. If you were, consider this a gift: the world isn't going to be crushed into an infentessimly small point of mass!

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