Astronomers spot hot gas bubble zipping around black hole at our galaxy's centre: Watch video

Astronomers have detected a hot bubble of gas orbiting Sagittarius A*, the supermassive black hole four million times more massive than our Sun that resides at the centre of our Milky Way. The observations were made using the Atacama Large Millimeter/submillimeter Array (ALMA) observatory in the Chilean Andes during a campaign by the Event Horizon Telescope (EHT) Collaboration to image black holes.

Some of the observations were made shortly after a burst or flare of X-ray energy was emitted from our galaxy's center, which was spotted by NASA's Chandra X-ray Observatory. According to the researchers, these kinds of flares are thought to be associated with so-called ‘hot spots’ - hot gas bubbles that orbit very fast and close to the black hole. 

The astronomers behind this discovery predict that the gas bubble orbits very close to the black hole, at a distance about five times larger than the black hole’s boundary or “event horizon”. According to the team, the hot spot becomes dimmer and brighter as it goes around the black hole, as indicated in this animation.

"We think we're looking at a hot bubble of gas zipping around Sagittarius A* on an orbit similar in size to that of the planet Mercury, but making a full loop in just around 70 minutes. This requires a mind-blowing velocity of about 30% of the speed of light," said Maciek Wielgus of the Max Planck Institute for Radio Astronomy in Bonn, Germany, the lead author of the study published in the Astronomy & Astrophysics journal.

Check out this video shared by the European Southern Observatory, which shows an animation of the gas bubble orbiting around the Milky Way's supermassive black hole:

Video Credit: EHT Collaboration, ESO/L. Calçada (Acknowledgment: M. Wielgus)

What's next?

Ivan Marti-Vidal of the University of València in Spain, co-author of the study said, "In the future, we should be able to track hot spots across frequencies using coordinated multiwavelength observations with both GRAVITY and ALMA - the success of such an endeavour would be a true milestone for our understanding of the physics of flares in the Galactic centre."

The team also hopes to directly observe the orbiting gas clumps with the EHT, to probe ever closer to the black hole and learn more about it