
A Glimpse into the Heart of a Quasar - Pharmakon
https://www.nature.com/articles/d41586-018-07538-z
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mirimir
It's a great article. But it's odd that it didn't mention work on our local
(fortunately quiet) quasar, Sagittarius A*. Although there's too much dust for
visible observations, it's just so damn close. And there's been some great
imaging work at gamma, x-ray and radio wavelengths. Although I don't believe
that there's a substantial accretion disk, we can actually observe stuff
that's orbiting the black hole.

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revscat
Sag A* is not a quasar. If it were, it would be the brightest thing in the sky
by several orders or magnitude.

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mirimir
It's a potential quasar. It's just that there's not much accretion happening
right "now". And it does occasionally flare.[0] Also, I don't believe that we
have the data to exclude the possibility that something big is heading inward.
We only see stuff that's close enough to get hot enough.

But of course, given that we're near the galactic plane, neither jet points at
us. And although, as I recall, the jets are somewhat off-axis, they're not off
in our direction.

0) [https://arxiv.org/abs/1709.09896](https://arxiv.org/abs/1709.09896)

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kijin
It might become a full-blown quasar when the Andromeda Galaxy collides with
the Milky Way ~4.5 billion years from now. We'd better take that into
consideration when we start planning for the death of our Sun ;)

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mirimir
Based on what we've observed, one could likely estimate the amount of
accretion needed to make Sag A* visible from Earth. Or bright enough to fry
us. It'd be a huge stretch for me to do that. But I bet that it's a _lot_ less
than Andromeda. I mean, there could be a substantial black hole, maybe 50-100
years out, and I doubt that we could detect it now :)

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starclaps
Just today I read some comment about „Science is slowing down“, but honestly,
there is so much astonishing progress (like this one) purely motivated by
curiosity - it’s truly motivating and inspiring!

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taneq
I'm personally convinced that the "science is slowing down" perception is a
consequence of actual progress speeding _up_ while the time taken for new
discoveries to percolate into the common consciousness is increasing. You look
back on discoveries that have had time to percolate, and you see a rapid ramp
up. Then you look at the past few years, and you see less going on because
it's all still in labs and obscure research papers and the like.

Also, it's hard to know which discoveries are hugely important when they're
still drowned out in dross. It's like the way '70s music is "the best music",
because we've forgotten the tons and tons of crud '70s music.

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jmcqk6
There is an effect where the progress of science can stay the same, but the
progress is in expanding details.

So instead of Einstein reshaping our understanding of spacetime, we gain a
more detailed understanding of the consequences of that discovery. The average
cosmologist these days probably has a superior understanding of relativity
than even Einstein did.

Consider the map of human knowledge to be an ever expanding tree. If you have
growth happening at the same rate, it can seem slower, because it's hard to
grasp the full breadth of the growth now. I don't know if I'm explaining it
that well.

Our understanding of the universe is extremely detailed compared to even 50
years ago, and we continue to advance rapidly. It's just that advancement is
spread out much more, and is much, much more detailed and nuanced.

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SeanFerree
Awesome article!

