A star appears to have collapsed straight into a black hole without supernova (2017)

77 pointsposted 16 days ago
by bfeist

39 Comments

andrewstuart

16 days ago

It’s a weird and scary thought.

Imagine seeing that up fairly close - a massive star just shrivel into a black hole and wink out.

pavel_lishin

16 days ago

I'd love to see a realistic render of this.

bell-cot

16 days ago

It's been a while since I crawled Wikipedia's rabbit hole on this - but I recall there being regions of the stellar "mass vs. metallicity" graph in which direct collapse to a black hole is the expected outcome.

Is there an astrophysicist in the house?

metalman

16 days ago

not an astro anything, but the easy question is how does the sun switch off it's light output so suddenly as to cause a perfect garavitational collapse presumably it has to be a large metal rich star and exist without too much local gas or a companion star one thing is clear at this point is that the variety of stelar and galactic variability is much larger than what was predicted even a few decades ago, though the idea of a star just neatly removing itself from this universe when it's done, is very strange indeed

madaxe_again

16 days ago

It doesn’t necessarily switch anything off or collapse - it’s possible for a star of the right mass and density to simply end up with a core that is held up only by degeneracy pressure, and the core slowly shrinks as it cools until it lies within its schwarzschild radius, and the rest of the star is either quietly consumed by this relatively slow process, or just escapes as though nothing much happened. Which from the outside looks like the star just turning off.

MoonGhost

16 days ago

It cannot just escape without a push as the gravity is still the same?

saltcured

16 days ago

I assume they meant until all the mass collapses across the threshold, the remaining shell of the star outside is still radiating energy and a "solar" wind, which is particles escaping. So some is escaping away while some is slipping under.

amelius

16 days ago

What is the timespan of such an event?

ben_w

16 days ago

Depends how you define the boundry of the event itself, both in space and in time.

Stellar cores are relatively small, and the infalling matter is essentially in freefall at high g, gets to a significant fraction of c in about 0.1 seconds.

The visible disk of a red supergiant — of the kind that can supernova or surprise us by failing — is on the order of multiple AU radius, so speed of light limits there are in the tens of minutes.

mikhailfranco

15 days ago

  As many as 30 percent of such stars 
  may quietly collapse into black holes
  no supernova required.
where 'such' refers to 25 solar mass stars.

Is that a significant contribution to 'dark matter'?

user

16 days ago

[deleted]

udev4096

16 days ago

(2017)

verbify

16 days ago

[22 million years ago]

wizzwizz4

16 days ago

That's subjective. Objectively, all we can say is that it happened before 2017.

gerad

16 days ago

No it’s relative. ;)

pavel_lishin

16 days ago

Well, it certainly didn't happen tomorrow.

exe34

16 days ago

in some reference frames, yes.

wizzwizz4

16 days ago

No, not if we've observed it. There are predicted historical events which can be shunted into the future by running away bravely, but if you've seen them happen, you can only change how long ago.

exe34

16 days ago

not for us, but in some other reference frame.

wizzwizz4

16 days ago

If by "reference frame" you mean "observer who lives in the past", then yes: the past is sometimes the future of a more distant past.

exe34

15 days ago

no, relativity allows for reference frames where the event hasn't happened yet, even though it has happened for you. there's no simultaneous "it has already happened" for all frames.

wizzwizz4

14 days ago

There is if the event is in the past or future light cone. If A sends a signal to B, and B receives it, there is no reference frame where that signal went backwards in time. (Unless you count exotic ones, like "particle with imaginary rest mass is zooming along at thrice the speed of light", but you can't accelerate to such a reference frame so I don't.)

user

16 days ago

[deleted]

Scarblac

16 days ago

That was in 2017, it's 22000008 years ago now.

subscribed

15 days ago

Time doesn't pass uniformly :)

roman_soldier

16 days ago

Could be an advanced civilisation sucking all the stars energy into the back of their spaceship.

m4rtink

16 days ago

More likely just someone feeding all the mass of the star to a black hole for industrial purposes - eq. a Deep Well Industrial Zone: https://www.orionsarm.com/eg-article/464790d2497de

Orions Arm even has a story about how such process might look like: https://www.orionsarm.com/eg-article/46709da5de6be

You basically let material stream into a black hole, it forms an acreation disk which gets very hot and dense even before the material actually falls into the black hole. The temperatture and pressure is high enough to trigger nucleosynthetic fusion reactions that generate heavy elements from lighter stuff, like the abundant hydrogen and helium. And a lot of "process heat" that can be used as energy source for other purposes. :)

adonovan

16 days ago

Perhaps a superadvanced civilization training an AI model on all remaining negative entropy in their solar system so they can more effectively create realistic propaganda for the upcoming election on their now rather chilly mars colony.

chgs

16 days ago

And then where does it go?

user

16 days ago

[deleted]

user

16 days ago

[deleted]

keepamovin

16 days ago

Or something just moved in front of it. It did not rage against the dying of the light, the definition of out with a whimper.

WhitneyLand

16 days ago

Like people spent years of their life scientifically studying the problem and didn’t think of this before making the claim?

It was multi-wave analysis not just visible light, IR spread can differentiate this.

It’s been missing since 2015. Probability of something being large enough to cover the star and stay on a path completely obscuring it for 10 years is shall we say, not likely.

It didn’t rage against the dying of the light, it just switched off.

y42

16 days ago

>As many as 30 percent of such stars, it seems, may quietly collapse into black holes — no supernova required.

gpvos

16 days ago

TFA says the astronomers checked for that. It's still a possibility, but pretty unlikely.