The Black Hole That Switched Back On

Astronomers using the eROSITA telescope have observed a rare “changing-look” active galaxy over a billion light-years away.

The galaxy HE 1237−2252 dramatically faded in X-rays before unexpectedly returning to its original brightness, revealing a supermassive black hole rapidly changing its feeding activity in real time.

Scientists believe the phenomenon was driven by powerful thermal waves moving through the black hole’s accretion disk rather than obscuring dust clouds. The discovery offers an extraordinary opportunity to study how black holes evolve, reignite, and influence the energetic life cycles of distant galaxies.

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