Hacker News

bfeist
A star appears to have collapsed straight into a black hole without supernova (2017) science.nasa.gov

amelius5 hours ago

What is the timespan of such an event?

ben_w4 hours 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.

andrewstuart4 hours 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_lishinan hour ago

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

bell-cot3 hours ago

Here's a short (12 page) and pretty easy article from The Astrophysical Journal (2003), about end of life for massive stars. And why some would "directly" collapse (no big & bright supernova) into black holes.

https://open.clemson.edu/cgi/viewcontent.cgi?article=1006&co...

[deleted]6 hours agocollapsed

udev40966 hours ago

(2017)

verbify4 hours ago

[22 million years ago]

wizzwizz42 hours ago

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

gerad2 hours ago

No it’s relative. ;)

pavel_lishinan hour ago

Well, it certainly didn't happen tomorrow.

bell-cot6 hours 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?

magicalhippo2 hours ago

Seems this is the case for both supermassive black hole formation[1][2], and stellar direct-collapse black holes due to failed supernova[3].

But yeah, just a layman so hopefully someone knowledgeable chimes in.

[1]: https://doi.org/10.1093/mnras/staa863

[2]: https://doi.org/10.3847/1538-4357/acda94

[3]: https://arxiv.org/abs/2503.23856

metalman5 hours 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_again5 hours 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.

MoonGhost4 hours ago

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

roman_soldier5 hours ago

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

m4rtink3 hours 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. :)

NKosmatosan hour ago

Or it could be the sun eating dragon :-)

Joking aside, it could be a Kardashev Type II (or higher) civilization. https://en.wikipedia.org/wiki/Kardashev_scale

They could have used a dense Dyson sphere to “suck” the energy of the star, but if that was the case we would be able to detect its infrared radiation. https://en.wikipedia.org/wiki/Dyson_sphere

Anyway, I prefer the giant star eating dragon alternative ;-)

chgs25 minutes ago

And then where does it go?

[deleted]3 hours agocollapsed

[deleted]3 hours agocollapsed

keepamovin5 hours 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.

WhitneyLand2 hours 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.

y424 hours ago

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

gpvos2 hours ago

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

hn-front (c) 2024 voximity
source