DisprovedChanged2022

We can infer our galaxy's central black hole, but we'll never see it

The old claim turned out to be wrong and was rejected by evidence.

TaughtA supermassive black hole, Sagittarius A*, sits at the center of the Milky Way; we know it from the orbits of stars whipping around something invisible. But it is 27,000 light-years away and, by definition, emits no light, so an actual image of it is impossible.

NowOn 12 May 2022, the Event Horizon Telescope collaboration released the first image of Sagittarius A*: a glowing ring of superheated gas encircling the dark shadow of the black hole itself, direct visual confirmation of the object at our galaxy's heart.

What actually happened

You cannot photograph a black hole, but you can photograph its silhouette. The EHT linked radio dishes across the planet into a virtual telescope the size of Earth, sharp enough to resolve the ring of light bent around Sagittarius A* by its own gravity, the 'shadow' whose size matches what Einstein's equations predict for four million solar masses.

This followed the same team's 2019 image of the giant black hole in galaxy M87; Sagittarius A* was harder because it is smaller and flickers fast, so the picture is a careful average of thousands of reconstructions. The specific thing taught, that our galaxy's black hole could be inferred but never seen, no longer holds.

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