Jun 18, 2022 - Science

Scientists find possible black hole wandering the Milky Way

Artist's illustration of a black hole in the Milky Way
Illustration of a black hole in the Milky Way. Image: FECYT, IAC

Astronomers have discovered what they think could be a black hole roaming the Milky Way all by its lonesome.

Why it matters: The discovery of this possible black hole will allow researchers to pin down exactly how many of these objects may exist out there in our galaxy and how far away they might be, helping illuminate the nature and evolution of these mysterious objects a little bit more.

  • These stellar-mass black holes are typically found with companion stars, whose gas can fall onto the black hole, a stellar event that can be seen with X-ray telescopes.
  • This possible black hole, however, has no such companion.

What's happening: The Hubble Space Telescope was able to measure the object — which is about 5,000 light-years from Earth — during observations that took place over the course of six years.

  • Two teams of scientists used the Hubble to observe the object, whose extreme density warped the light of a star 19,000 light-years away from Earth as it passed between that star and the telescope.
  • Because of this discovery, scientists now think the nearest black hole of this kind is no more than 80 light-years away from Earth.

But, but, but: It's possible the object isn't a black hole at all.

  • One team of researchers found the object is about seven times the mass of the Sun, firmly putting it in the mass range of a black hole.
  • The other team estimates the object is between 1.6 and 4.4 solar masses. The lower range would make it a neutron star, and the higher range would make it a black hole.
  • "As much as we would like to say it is definitely a black hole, we must report all allowed solutions. This includes both lower-mass black holes and possibly even a neutron star," Berkeley's Jessica Lu, who is on the team with the lower mass estimate, said in a statement.
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