So, What Does A Black Hole Look Like?

From Scientific American:

At six simultaneous press conferences around the globe, astronomers on Wednesday announced they had accomplished the seemingly impossible: taking a picture of a black hole, a cosmic monster so voracious that light itself cannot escape its clutches.

This historic feat, performed by the Event Horizon Telescope (EHT)—a planet-spanning network of radio observatories—required more than a decade of effort. The project’s name refers to a black hole’s most defining characteristic, an “event horizon” set by the object’s mass and spin beyond which no infalling material, including light, can ever return.

8 replies on “So, What Does A Black Hole Look Like?”

  1. That’s an impressive achievement.

    Even if it looks more like a picture of Uranus.

    Get it? Get it? It looks more like—

    Ah, yeah. Ok. I will show myself to the door now.

    • Fun fact: the original pronounciation of “Uranus” stressed the first syllable and pronounced the “a” with the short “i” sound, but teachers got tired of all the “urine” jokes so they collectively agreed to teach students that it was pronounced differently.

      That really didn’t work out the way it was supposed to.

      • I go with an older-school “Ouranus” (OO-ranus) pronunciation, which seems the best of several problematic options.

        Next week, we’ll discuss the confusion created by “laid,” “lied,” and “layed,” and why Geeky/Nerdy/Dorky probably should have thought a bit before identifying its rules as being “for solo or group play.”

    • Actually, they took a picture of the accretion disk. As objects fall towards a rotating black hole (and virtually all of them rotate; net angular momentum, net electric charge, and total mass are the three quantities retained of the material that falls into them) they accelerate. Accelerate too rapidly, and you start to emit Bremstrahlung, or braking radiation, when you go around a corner. While the event horizon and everything within will be black, there is some radiation from things immediately surrounding it that was emitted in this fashion. The Doppler shift from escaping the black hole is pretty severe, sending what would be X-rays and UV rays into the radio part of the spectrum, but it’s detectable.

      • So, they took a picture of the scraps of things that have been consumed by the black hole, not the actual black hole, right?

        I apologize for my reductionist approach, I do think it’s a great achievement and I am interested to see where it goes, I am just trying to wrap my brain around the idea that we were trying to see something that was famous for being the definition of not being able to be seen.

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