Where once a star shone, scientists see evidence of a baby black hole

The leftovers from a star that blew up in a galaxy some 50 million light-years away may be giving astrophysicists their first look at an infant black hole – an object whose gravity is so immense that even light fails to travel fast enough to escape its grip.

The evidence comes in the form of X-ray emissions from the object, emissions that can escape because they come from material that is on the verge of being sucked into the cosmic maw, but hasn't been drawn over the brink yet.

The researchers reporting the discovery – a team from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. – caution that at least one other plausible mechanism could be generating the X-rays, such as the one driving emissions from the Crab Nebula, the remains of a star only 21 light years from Earth whose explosion as a supernova sky watchers spotted in 1054 AD.

In that case, no black hole formed from the supernova. Instead, the remnant of the original star is a rapidly spinning neutron star, or pulsar, which packs the mass of an object like the sun into a ball only 12 miles across. Energy from the neutron star excites the shell of material expanding from the original explosion, giving off X-rays as well as radiation at other wavelengths.

Researchers say supernova explosions are far more likely to produce neutron stars than so-called stellar-mass black holes, so if the emissions the team has studied are coming from a black hole, the discovery would offer rare insights into a rare process.

Whatever is driving the X-ray emissions the team tracked, this latest find gives researchers the opportunity to gather long-sought details about the death throes of massive stars – a process that astrophysicists say is responsible for seeding the universe with chemical elements heavier than primordial hydrogen and helium.

"I'm pretty excited about this discovery, regardless of whether it turns out to be a young black hole" or a nebula energized by a pulsar, says Alexei Filippekno, an astronomer at the University of California at Berkeley who studies supernovae and was not a member of the team reporting the results.

A 1979 supernova

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