May 19, 2021 - Science

Big and little black holes feed the same way

Galaxies like this one, M104, are thought to house supermassive black holes at their centers
Galaxies like this one, M104, are thought to house supermassive black holes at their centers. Photo: NASA/STScI/AURA

No matter the size of a black hole, they all appear to feed the same way, according to a new study.

Why it matters: Black holes are some of the most extreme objects found in our universe. By studying the way they grow, scientists should be able to piece together more about how they work.

What they found: The study in the Astrophysical Journal suggests all black holes go through a similar cycle when feeding whether they are about 10 times the mass of our Sun or a supermassive black hole at the center of a galaxy.

  • Scientists know that when relatively small black holes get a large helping of gas or dust, they move into a phase where the object feeds from a disc surrounding the black hole — called an accretion disk.
  • As the disc collapses, the area around the black hole can glow brightly in X-ray, and that eventually gives way to the object becoming quiet again. This all happens over the course of a few weeks to months.
  • Researchers thought this process would take too long for them to watch the whole thing play out with a supermassive black hole, but the new study found feeding can speed up if the black hole gets a large meal all at once, like when it shreds a star.

How they did it: The researchers behind the new study watched as a supermassive black hole 860 million light-years away gobbled up a star in 2018, giving them a firsthand view of how these huge black holes eat.

The bottom line: “When you throw a ball of gas at them, they all seem to do more or less the same thing," study author Dheeraj Pasham, of MIT, said in a statement. "They’re the same beast in terms of their accretion."

  • "We’ve demonstrated that if you’ve seen one black hole, you’ve seen them all, in a sense."
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