FOR the first time, astronomers have seen a black hole gobbling material from
a nearby star and spitting it out nearly as fast as light. This should help
confirm how these dense objects emit jets of matter.
Black holes form when massive stars collapse to a tiny volume at the end of
their lives. Many are orbited by companion stars. Matter from a stellar
neighbour can fall towards the hole, where it swirls around it in a fast-moving
disc, heats to millions of degrees and releases X-rays.
Astronomers observing one such black hole in the constellation Aquila have
noticed that it sometimes moves into an unstable phase. Every half hour, X-rays
from the hottest inner part of the disc fade dramatically in just three
seconds鈥攁 sign that the inner matter has somehow 鈥渧anished鈥�. 鈥淚t鈥檚 as if
something with the mass of Lake Superior just goes away,鈥� says Stephen
Eikenberry of the California Institute of Technology in Pasadena.
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Eikenberry and his colleagues found that infrared flares鈥攋ets of matter
shooting away from the hole鈥攁ppear each time the X-rays fade. Astronomers
thought the jets were material dumped from the inner disc, but this is the first
direct evidence. 鈥淲e鈥檝e never had a clear picture of how jets form,鈥� Eikenberry
told the American Astronomical Society in Washington DC last week. 鈥淏ut I think
we鈥檝e found the beginning of an answer.鈥�