Astronomers said on Thursday they had discovered a hot bubble spinning clockwise around the black hole at the center of our galaxy at “stunning” speeds.
The detection of the bubbles, which have only survived for a few hours, hopes to gain insight into how these invisible, insatiable galactic monsters work.
The supermassive black hole Sagittarius A* lurks in the center of the Milky Way, some 27,000 light-years from Earth, and its enormous gravity causes our galaxy to form its characteristic vortex.
In May, the first images of Sagittarius A* were revealed by the Event Horizon Telescope Collaboration, a collaboration linking radio antennas around the world designed to detect light disappearing into black holes.
One of the dishes, the ALMA radio telescope in the Chilean Andes, found something “very puzzling” in the Sagittarius A* data, said astrophysicist Maciek Wielgus of Germany’s Max Planck Institute for Radio Astronomy.
Just minutes before ALMA’s radio data collection began, the Chandra Space Telescope observed a “giant spike” in X-rays, Wielgus told AFP.
The burst of energy, thought to be similar to a solar flare on the sun, creates a hot bubble around the black hole, according to a new study published in the journal Astronomy & Astrophysics.
The bubble, also known as a hot spot, has an orbit similar to the orbit of Mercury around the sun, said lead author of the study, Virges.
But while Mercury took 88 days to make that trip, the bubble did it in just 70 minutes. That means it travels at about 30% the speed of light.
“So it’s definitely a very fast-spinning bubble,” Wielgus said, calling it “exciting.”
The scientists were able to track the bubble through their data for about an hour and a half — it’s unlikely to survive more than a few orbits before being destroyed.
This observation supports a theory known as MAD, Vierges said. “MAD is like crazy, but also MAD like a hysteretic disc,” he said.
The phenomenon is thought to occur when the presence of such a strong magnetic field at the mouth of a black hole prevents matter from being sucked inside.
But this material keeps building up, creating “flux bursts,” Wielgus said, which disrupt the magnetic field and cause bursts of energy.
By understanding how these magnetic fields work, scientists hope to build a model of the forces that govern black holes, which remain shrouded in mystery.
The magnetic field can also help indicate how fast the black hole is spinning — which could be especially interesting for Sagittarius A*.
Although Sagittarius A* is 4 million times the mass of the sun, its light is only about 100 suns of energy, “which is extremely unremarkable for a supermassive black hole,” Wielgus said.
“This is the weakest supermassive black hole we’ve ever seen in the universe — we see it because it’s so close to us.”
But it could be a good thing that there’s a “hungry black hole” at the center of our galaxy, Wilgers said.
“Living next to a quasar,” which can radiate the energy of billions of suns, “would be a scary thing,” he added.