NASA's Spacecraft Uncovers New Insights About Milky Way's Supermassive Black Hole

The supermassive black hole at the center of our galaxy is usually seen as quiet and inactive, but new findings show it was far more active in the past. Scientists have discovered that this black hole, called Sagittarius A* or Sgr A*, produced powerful flares over the last 1,000 years, surprising astronomers, reported Space.com.

This discovery was made with the help of the international XRISM spacecraft, a joint mission of Japan, Europe, and the United States. The finding could give scientists a new perspective on the evolution of supermassive black holes and their impact on the galaxies around them.

The results astonished astronomers. Stephen Dikerby, the team leader from Michigan State University, said that his training in X-ray astronomy had not prepared him for such a discovery and described it as an exciting new capability that provides entirely new tools for research.

Black holes themselves do not emit light because their gravitational pull is so strong that nothing, not even light, can escape once it crosses the event horizon. However, the gas and dust surrounding them are heated to extreme temperatures due to intense gravity and friction, resulting in powerful X-ray flares. Sgr A*, which has a mass equivalent to four million suns, was not previously known to produce such emissions.

This understanding changed when Dikerby and his team pointed XRISM toward a large gas cloud near the galactic center. By carefully studying the X-rays emanating from this molecular cloud, they discovered that it was reflecting X-rays from a past flare of Sgr A*, acting like a cosmic mirror.

XRISM's high sensitivity, made possible after its launch in 2023, allowed scientists to precisely measure the energy and composition of the X-rays. This enabled them to understand the cloud's motion and rule out other potential sources of the X-ray emission, such as cosmic rays.