Astronomers Creep Up to the Edge of the Milky Way’s Black Hole

https://www.quantamagazine.org/astronomers-creep-up-to-the-edge-of-the-milky-ways-black-hole-20181030/

by digital55 • 8 years ago

89 19 8 years ago

Astronomers call it Sagittarius A* (pronounced “A-star”).

Why do astronomers call the black hole "A Star" when they know better than anyone else that it's not a star, but a black hole?

Why don't we call it "Sagittarius A-black hole"?

scentoni• 8 years ago

The asterisk has nothing to do with indicating it is a star.

The name Sgr A* was coined by Brown in a 1982 paper because the radio source was "exciting", and excited states of atoms are denoted with asterisks.

https://en.wikipedia.org/wiki/Sagittarius_A*

teh_klev• 8 years ago

Direct link to paper:

https://www.aanda.org/articles/aa/pdf/forth/aa34294-18.pdf

_cs2017_3• 8 years ago

The title would be a great sentence to test the quality of machine translation.

jamesblonde• 8 years ago

"Astronomer krypa upp till kanten på Mjölkets svarta hål" (creep up to the edge of the milk's black hole) - Swedish

BrandonMarc• 8 years ago

Needs more "bork"

Odenwaelder• 8 years ago

"Astronomen schleichen sich bis an den Rand des Schwarzen Lochs der Milchstraße"

Perfect german translation.

Hei1Fuya• 8 years ago

A decent translation, but maybe not quite idiomatic. Herantasten or annähern instead of schleichen feel more appropriate.

_cs2017_3• 8 years ago

Oh so the word for "creep" they used in German is appropriate for the metaphorical meaning of "investigating/watching"? Does the most direct dictionary translation of "creep" happen to fit here?

If the translator figured out that this is a figurative meaning and intentionally picked a suitable translation, I'm very impressed!

trulyrandom• 8 years ago

"Astronomen kruipen omhoog naar de rand van het zwarte gat van de melkweg" - Dutch

Close, but not quite.

nunobrito• 8 years ago

"Astrónomos espiam o limite da Via Láctea"

Portuguese/Galician

_cs2017_3• 8 years ago

Is this any good?

sedatk• 8 years ago

“Gökbilimciler Samanyolu'nun Kara Deliğinin Kenarına Kadar Sürünüyor”

Turkish, and I’m amazed at its accuracy. Turkish has been phenomenally hard to translate from English. Google has done a great job there.

pontifier3• 8 years ago

The strawberry seed apparent size comparison stopped me cold. That's incredibly tiny, and I'm in complete awe at this feat of humanity.

Cthulhu_• 8 years ago

It's a bit hard to visualize because we're used to things like heat shimmer, fog, the curvature of the earth and the very air itself blocking our view. Actually that's what those observatories have to keep in mind as well, but only about 100km of it instead of the distance as mentioned in the article.

gmiller123456• 8 years ago

It's not the size of something that makes it visible, but its brightness. Without actually doing the calculations, I'd bet there are stars you can see with your naked eye that are similar in apparent size or even smaller. In order to see detail, you'd need a lot of magnification. But your eye or a camera are able to detect that "something" is there due to the fact that there a lot of photons coming from that direction. The article talks about them observing dips in brightness, so they were probably just looking at a single pixel, or a handful of pixels at best.

pontifier3• 8 years ago

They described seeing a change in position at that scale. Brightness is one thing, but detecting an angular change like that is mind boggling.

It feels like you'd have to start compensating for things like plate tectonics and daily variation in the earths rotation due to melting glaciers to get that kind of accuracy.

pontifier3• 8 years ago

The question in my mind is how can you point a telescope when the accuracy is that high. A heavy truck parked 100 meters away probably deforms the ground locally enough to change things.

Steel probably wobbles like jello when motion at those scales matters.

yourapostasy• 8 years ago

This brings to my mind Isaac Arthur's lecture "Civilizations at the End of Time: Iron Stars" [1]. He posits that a Kardashev Scale 3 civilization might use a galactic black hole to survive 10^100 entropic years of what he calls the "Black Hole Epoch". Hearing about this possible giant blob of plasma orbiting our galactic black hole makes me wonder if he and his team can come up with plausible explanations that the plasma is actually some construct of such a civilization, like perhaps a "construction site generator" as they're building their "bunker against entropic time" amongst the black hole.

The really neat part of the lecture is towards the end, in his description of time winding down into thermodynamic equilibirum, a Boltzmann Brain fluctuating out of the equilibrium's randomness, and restarting the universe with another Big Bang. That's fascinatingly close to universe origin stories in Abrahamic religions, and echoes Hindu religious cosmological cyclicality. One aspect I didn't see touched upon is the possibility that our universe and we are simulations inside that Boltzmann Brain. And then there are the arguments that we do not want Boltzmann Brains [2].

Now if only the religious adherents in all our nations duking it out against other humans for not having the "right" religion could turn their cognitive surplus (poured into their religion) outwards to helping illuminate more upon these near-metaphysical physics challenges, we might actually get somewhere. After all, our best guess at the moment is we're halfway out of time in the universe.

[1] https://www.youtube.com/watch?v=Pld8wTa16Jk

[2] http://www.preposterousuniverse.com/blog/2013/08/22/the-higg...

Astronomers Creep Up to the Edge of the Milky Way’s Black Hole

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