Researchers have identified that the supermassive black hole located at the center of the Milky Way exhibits significant activity, continuously emitting a series of flares into space. A recent study conducted using NASA’s James Webb Space Telescope has unveiled a spectrum of light emanating from the black hole, known as Sagittarius A*, specifically from its accretion disk, which is the ring of swiftly rotating material that encircles it.
Some of these flares are fleeting, resembling the brief flickers of a candle and lasting only seconds, while others are substantial eruptions, generating several intensely bright jets daily. The newly published research in The Astrophysical Journal Letters is expected to aid astrophysicists in gaining a deeper understanding of black holes and their interactions with nearby gas and dust, potentially offering new insights into the Milky Way’s evolution.
"We observed a continuously changing, bubbling brightness," remarked Farhad Yusef-Zadeh, the astronomer from Northwestern University who led the study. "And then suddenly a big burst of brightness appeared. Afterward, it would diminish. No pattern was discernible in this activity, suggesting it may be random."
The analysis conducted by scientists at the Space Telescope Science Institute in Baltimore, responsible for managing the Webb and Hubble Space Telescopes, is described as the most comprehensive study of Sagittarius A* to date. The research is based on 48 hours of observation, collected over eight to ten-hour sessions during the course of a year.
Initially considered a theoretical concept 50 years prior, supermassive black holes are now accepted as scientific reality and are being photographed using vast, synchronized radio dishes on Earth. These massive entities, which are millions to billions of times the mass of the sun, are believed to reside at the centers of nearly all large galaxies.
It is understood that approaching a black hole results in inevitable destruction; any matter venturing too close reaches a point of no return. However, scientists have noted a peculiar phenomenon at the boundaries of black holes’ accretion disks, akin to water swirling around a bathtub drain. Occasionally, some matter can be unexpectedly redirected, causing high-energy particles to be expelled as jets, extending in opposite directions, though the mechanics behind this occurrence are not yet fully understood.
The data from the Webb telescope, collected over 9.5 hours on April 7, 2024, showcases a significant flare toward the end. Yusef-Zadeh and his team are investigating this further, comparing the new observations to solar flares, yet capable of being visible across 26,000 light-years. The Webb Telescope detected changes in brightness over short time periods, suggesting the source is the black hole’s inner disk, close to its event horizon, the point of no return.
Yusef-Zadeh hypothesizes that the largest flares might be analogous to magnetic reconnection events, where two magnetic fields collide and release particles traveling near the speed of light. Shorter bursts may be caused by minor disruptions in the accretion disk, similar to solar flares resulting from the sun’s magnetic field becoming tangled and erupting.
"Of course, the processes are more intense due to the extreme and energetic environment around a black hole," he stated, "but the Sun’s surface also exhibits bubbling activity." The researchers plan to continue observing Sagittarius A* for an extended, uninterrupted duration to ascertain whether the flares occur randomly or follow a pattern.