NASA detects 'heartbeat' of pint-sized star-sucker In what is turning out to be one of the best months ever for black-hole fanbois, a team of Dutch, Italian, and US space boffins has detected the "heartbeat" of what appears to be teensiest, weensiest black hole ever discovered. "Just as the heart rate of a mouse is faster than an elephant's, the heartbeat signals from these …
A spectrum easily differentiates between astronomical X-rays produced by synchrotron radiation and hot material. Since matter falling into a black hole can potentially convert a significant fraction of its mass to energy (by friction, tidal and other effects), there's plenty available to heat it to the point where thermal X-rays will be produced.
Nope - a solar mass black hole takes ~2x10^67 years to evaporate completely (and it's an exponential runaway effect, so for the first 10^67 years not much mass is lost), bigger ones correspondingly slower. And with a radiation temperature of 10^-7 K, it would (for the 'foreseeable' future) actually gain mass from the cosmic microwave background.
The power in the Hawking radiation from a solar mass black hole turns out to be a minuscule 9 × 10E−29 watts. Bigger bodies radiate less than smaller, so a 3 solar mass black hole wouldn't lose any appreciable amount of mass over the lifetime of the galaxy.
The only blackholes that could have shrunk appreciably are those that were created in the big bang itself and started off much smaller than any blackhole created by a supernova could be.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2024
