Q&A: Black Holes

Q:
Does Chandra indicate more Quasar/Super Massive Black Holes like PKS 0637-72 than previously were thought to exist in the early years of the universe? Studies I have read theorize the universe will fizzle out after a "Black Black Hole" era.

A:
The Chandra data indicates that the number of active black holes is about two or more times greater than previously thought. Among the most interesting long term results from Chandra will be greatly improved estimates of the number of stellar sized and supermassive black holes in the universe. The "Black Hole" era you mention may refer to the era in the far distant future after all the stars have burned out, elementary particles have decayed into neutrinos and gamma rays, and eventually, black holes evaporate by the Hawking process. The latter time is huge, being about a 100 trillion octillion yotta-years, or 1 followed by 65 zeroes, for a 10 solar mass black hole, and a quintillion times longer than that for a 10 million solar mass black hole! (1 yotta-year = a trillion trillion years).

For more information see our Field Guide section on Black Holes.