Scientists Discover Teeny Tiny Black Hole 277
AbsoluteXyro writes "According to a Space.com article, NASA scientists have discovered the smallest known black hole to date. The object is known as 'XTE J1650-500'. Weighing in at a scant 3.8 solar masses and measuring only 15 miles across, this finding sheds new light on the lower limit of black hole sizes and the critical threshold at which a star will become a black hole upon its death, rather than a neutron star. XTE J1650-500 beats out the previous record holder, GRO 1655-40, by about 2.5 solar masses."
Re:Probably Something Stupid (Score:2, Informative)
Re:Probably Something Stupid (Score:5, Informative)
The mass of the black hole is the most defining characteristic.
Re:15 miles across? (Score:3, Informative)
Yes that's what astronomers mean when they say how "big" a black hole is.
Re:Probably Something Stupid (Score:5, Informative)
A black hole, conventionally, consists of an event horizon surrounding a region of space from which you can't send information to the external world. This region of space is not a point, it has a well-defined circumference. (Because of the non-euclidean nature of general relativity, it doesn't actually have a well-defined radius (since you can't measure across the middle!) but people usually just consider the radius as if it were defined as the circumference divided by 2 pi, and don't worry about the fact that you can't actually measure it.)
At the center of the black hole is, according to general relativity, a point singularity, which indeed has no dimensions.
Re:We weren't the first (Score:3, Informative)
Re:As someone who skimmed A Brief History of Time (Score:3, Informative)
Theoretical limit is 1.4 Solar Masses (Score:3, Informative)
http://en.wikipedia.org/wiki/Chandrasekhar_limit [wikipedia.org]
Re:Size vs Age (Score:3, Informative)
At least, if I were a scientist and not someone pulling this directly out of my ass, that might be what is happening here.
Re:Size vs Age (Score:5, Informative)
But!
The temperature of a black hole can be defined by the rate at which Hawking photons are streaming away from it. In the case of a black hole of a few solar masses, this temperature will be in the nano-Kelvin (I think -- don't hurt me if I'm wrong by a few orders of magnitude). Now remember everything in the Universe is sitting in a bath of cold photons from the Big Bang (i.e. the microwave background). These photons have a temperature of ~4 Kelvin.
Therefore, black holes whose Hawking temperature is above the microwave background will be net *gaining* mass.
Which is all a long way of saying, no, this isn't a normal size black hole that has decayed over time. It must have been created at this mass (or smaller).
Re:That's nothing... (Score:5, Informative)
001 = First black hole created by LHC
Some people are afraid the LHC-001 is going to destroy the Earth.
Re:Probably Something Stupid (Score:5, Informative)
It was this tear that lead, if I recall, to the original conjectures of a white hole, and the Einstein-Rosen bridge.
Re:Is it smaller than this one? (Score:3, Informative)
Quantum Foam (Score:4, Informative)
Re:Probably Something Stupid (Score:2, Informative)
What you've described is a way that energy can be created from nowhere. If what you suggest were right, we'd all be doomed, as any small black hole would get bigger through Hawking radiation, and would then consume everything.
Re:Probably Something Stupid (Score:2, Informative)
From an observer's point of view, the objects never reach the event horizon. They just appear to move slower and slower.
Black hole's really do mess up any concept of Euclidean distance. The best way of picturing it, is that it is a hole in space-time; for all intents and purposes, the space inside the event horizon simply doesn't exist.