A slightly enlarged artist concept about the true shape of our warped and bending galaxy Milky Way. The black hole in the center of our galaxy is not just expected and astronomers don't know why. (Photo: Chao Liu, National Astronomical Observatories, Chinese Academy of Sciences))

Astronomers say they saw the supermassive black hole closest to Earth glowing "unpredictably bright" – and they didn't sure why.

The black hole, known as Sagittarius A * or Sgr A *, is four million times the size of the Sun and about 26,000 light years from Earth. Although no visible light can survive the gravitational pull of a black hole, astronomers observe hot gas as it falls near-infrared, the portion of the infrared spectrum closest to the light visible to the human eye.

"So we didn't really notice the four nights of observation this year. On one of the nights its brightness was almost twice as bright as the brightest measurement in the last 20 years," says Tuan Do, an associate scientist and deputy director of the galactic center team at UCLA, led the study. "That suggests that maybe something interesting is happening physically in the black hole region."

& # 39; We found what we thought was inappropriate & # 39 ;: First image of a black hole revealed [19659008] Here is a timelaps of images beyond 2.5 hours from May from @keckobservatory by supermassive black hole Sgr A *. Black holes have always been variable, but this is the brightest we have seen in the infrared to date. It was probably even brighter before we started observing that night!

– Tuan Do (@quantumpenguin) August 11, 2019