The Black Hole That Switched Back On
6/11/202641 min
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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First 90 secondsSpeaker 10:00
[gentle music] Welcome to Bedtime Astronomy. Explore the wonders of the cosmos with our soothing bedtime astronomy podcast. Each episode offers a gentle journey through the stars, planets and beyond, perfect for unwinding after a long day. Let's travel through the mysteries of the universe as you drift off into a peaceful slumber under the night sky.
Speaker 2· Host0:24
I want you to start by just, um, taking a moment to imagine something that completely defies our standard everyday understanding of the cosmos.
Speaker 3· Host0:36
Right.
Speaker 2· Host0:36
Because, you know, when you look up at the night sky, it feels timeless, it feels static.
Speaker 3· Host0:41
Mm.
Speaker 2· Host0:41
Eternal, really. The constellations you see tonight are... well, they're the exact same ones the ancient Greeks looked at.
Speaker 3· Host0:47
The same ones the Egyptians mapped out, yeah.
Speaker 2· Host0:48
Exactly. But right now I want you to picture a super massive black hole, and it is sitting in the dark 1.3 billion light years away from where you are sitting right now.
Speaker 3· Host1:01
Which is a distance that's almost impossible for the human brain to process.
Speaker 2· Host1:04
It really is.
Speaker 3· Host1:05
Yeah.
Speaker 2· Host1:06
Just to put that distance into perspective, 1.3 billion years ago, the only life on Earth was microscopic single-celled organisms floating in the ocean.
Speaker 3· Host1:13
Yep.
Speaker 2· Host1:13
The light from what we are about to discuss today has been traveling through the absolute void of space for all that time just to reach our telescopes.
Speaker 3· Host1:21
It's staggering.
Speaker 2· Host1:23
So this black hole is a cosmic engine of unimaginable power. Now imagine that engine seemingly reaching