Astronomers using the James Webb Space Telescope have spotted flickering lights around the supermassive black hole at the center of our Milky Way galaxy. These lights appear in rapid bursts, some lasting just seconds, while others shine exceptionally bright each day.
This research provides the most comprehensive view we’ve ever had of Sagittarius A*, the Milky Way’s central black hole, revealing its intense activity over a longer period than we’ve seen before.
While black holes themselves cannot be seen, the flares of light come from the swirling gas and dust around them. This swirling, known as the accretion disk, creates an impressive display of brightness. A new study detailing these observations has been published in The Astrophysical Journal Letters.
Researchers think the flares originate from the edge of the accretion disk, just outside the black hole’s event horizon. This is the point where gravity’s pull is so strong that nothing, not even light, can escape, as explained by NASA.
“We observed a constantly changing brightness,” said Farhad Yusef-Zadeh, a professor at Northwestern University. “Then suddenly, there would be a big burst of light. This random activity was new and fascinating each time we looked.”
These observations could help us understand how black holes behave and interact with their surroundings. Black holes draw in gas and dust from objects that venture close. This material spins rapidly, forming the accretion disk and heating up, resulting in energy released as radiation and jets that escape the black hole’s grasp.
This radiation can impact gas distribution in galaxies and influence star formation, showcasing black holes as significant engines within the cosmic landscape.
Over the span of a year, Yusef-Zadeh and his team monitored Sagittarius A* for 48 hours, during which they recorded five to six significant flares each day, interspersed with smaller flashes.
“While flares are common in supermassive black holes, Sagittarius A* is unique,” Yusef-Zadeh mentioned. “It’s always active and changing. Each time we looked, we noticed something new.”
The variability of these flares likely comes from the unpredictable flow of material into the accretion disk. The short bursts of light might be triggered by small disturbances that compress hot gas, leading to quick flashes of radiation.
“It’s similar to solar flares,” Yusef-Zadeh explained. “The processes are more dramatic around a black hole due to its energetic environment.”
The larger flares may result from magnetic reconnection events—the collision of different magnetic fields near the black hole that releases high-energy particles.
Webb’s high-tech features allowed the research team to observe these phenomena in two different wavelengths simultaneously. “It’s like seeing colors in a world that was once black and white,” Yusef-Zadeh remarked.
These observations provided deeper insights into how the black hole’s brightness fluctuates over time. Tuan Do, an associate professor at UCLA, noted that deeper investigations of Sagittarius A* are necessary because the black hole’s behavior is always changing.
The research highlights a pattern: shorter wavelengths of light became brighter before longer wavelengths in the flares. This suggests that, as particles spiral around magnetic field lines, they lose energy quickly.
Previous studies and data from other observatories have noted similar changes in brightness, signaling a more complex understanding of the region around Sagittarius A*.
Mark Morris, a physics and astronomy professor at UCLA, points to historical evidence of even larger flares occurring in the past few centuries, possibly linked to the black hole consuming a nearby planet.
Although these cosmic activities seem intense, they pose no threat to Earth due to the black hole’s distance of 25,000 light-years. However, understanding these events helps astronomers learn how matter behaves under extreme conditions.
The study does not indicate that Sagittarius A* is currently having an unusual surge of activity, but the researchers wish to conduct extended observations to confirm this. They hope to determine if these flares exhibit any patterns or if they are completely random.
Gathering more data about Sagittarius A* could help astronomers simulate the behavior of accretion disks around different black holes and understand their activities better.
