Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Astronomers discover Milky Way’s biggest stellar black hole

theguardian.com

Post reply on HN
Print view View original

71–79 of 79 posts

Re: Astronomers discover Milky Way’s biggest stellar black hole

#71

Post by xpe »

Etheryte wrote: post #36
pxeger1 wrote: post #25

Earlier quoted context omitted.

Also “33 times more massive than the sun” means 34 times the mass of the sun.

Oh boy, this sent me down a memory lane. I remember arguing long and hard with my math teacher in elementary school that "two times as massive" and "two times more massive than" are not the same thing, but she did not agree. That's the point where I learned that the grownup world is weird and sometimes it's easier to just smile and nod.

"That's the point where I learned that the grownup world is weird"

That's a generous thing of you to say.

How many people really want to be proven wrong? I'd like to think I am. Maybe I should make a t-shirt:

    Happy to proven wrong *

    * But only by people who reciprocate

Re: Astronomers discover Milky Way’s biggest stellar black hole

#72

Post by alje »

TheDudeMan wrote: post #69

"Sagittarius A has the combined mass of several million suns. It lurks at the heart of the galaxy and formed not from an exploding star but the collapse of vast clouds of dust and gas." How is that known? Isn't "dust and gas" also how stars form?

Every galaxy we know of contains a massive black hole in the center. Until recently, the widely held belief was that massive black holes are formed via the process of mearging smaller black holes in large timeframes. However, once the JWST came online, astrophysicists discovered early massive black holes close to big bang that could not be explained by that cumulative process. There just was no time for the cumulative creation to a such large black holes.

So the current working hypothesis for massive black holes in galaxies is that they formed directly from the gravitational collapse of "vast clouds of gas and dust" with such high gravitational pressure that the core couldn't keep up, and the entire mass of gas and dust collapsed into a massive black hole. There is no supernova involvement; merely a direct transition into a black hole.

Of course, take my laic simplification into account.

Re: Astronomers discover Milky Way’s biggest stellar black hole

#73

Post by xpe »

Somewhat of an aside: I've grown tired of Roman mythology being foisted upon our planet names. But I'm even more tired of hearing NASA spokespeople talk about e.g. "exploring the heavens". At least they don't say "firmament" or refer to the Earth's mantle as being infernal.

Re: Astronomers discover Milky Way’s biggest stellar black hole

#74

Post by xpe »

papichulo2023 wrote: post #50
vorticalbox wrote: post #24

I was always under the impression there was only 1 black-hole in our galaxy, at it's centre.

There is even a theory about a mini black hole in our solar system pulling Uranus.

See e.g.

"What If Planet 9 Is a Primordial Black Hole?" by Jakub Scholtz and James Unwin [1]

[1] Phys. Rev. Lett. 125, 051103 – Published 29 July 2020 https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.12...

Re: Astronomers discover Milky Way’s biggest stellar black hole

#75

Post by exegete »

pfdietz wrote: post #68

Astronomers have not discovered the Milky Way's biggest stellar black hole. They have found the largest stellar black hole of all the galactic stellar black holes they've found so far. Since the Milky Way likely has 100 million stellar black holes, finding the largest is going to be quite a task. Bart: this is the biggest stellar black hole. Homer: this is the biggest stellar black hole so far .

I thought the “so far” was implied by science - this is what we know about the universe (so far).

Re: Astronomers discover Milky Way’s biggest stellar black hole

#76

Post by pfdietz »

exegete wrote: post #75
pfdietz wrote: post #68

Astronomers have not discovered the Milky Way's biggest stellar black hole. They have found the largest stellar black hole of all the galactic stellar black holes they've found so far. Since the Milky Way likely has 100 million stellar black holes, finding the largest is going to be quite a task. Bart: this is the biggest stellar black hole. Homer: this is the biggest stellar black hole so far .

I thought the “so far” was implied by science - this is what we know about the universe (so far).

Not a valid excuse here.

Re: Astronomers discover Milky Way’s biggest stellar black hole

#77

Post by vorticalbox »

Sharlin wrote: post #34
vorticalbox wrote: post #24

I was always under the impression there was only 1 black-hole in our galaxy, at it's centre.

Well, your impression was wrong then.

very wrong and I am a little sad I am getting down voted for not knowing something but here we are.

Re: Astronomers discover Milky Way’s biggest stellar black hole

#78

Post by kubanczyk »

alje wrote: post #72
TheDudeMan wrote: post #69

"Sagittarius A has the combined mass of several million suns. It lurks at the heart of the galaxy and formed not from an exploding star but the collapse of vast clouds of dust and gas." How is that known? Isn't "dust and gas" also how stars form?

Every galaxy we know of contains a massive black hole in the center. Until recently, the widely held belief was that massive black holes are formed via the process of mearging smaller black holes in large timeframes. However, once the JWST came online, astrophysicists discovered early massive black holes close to big bang that could not be explained by that cumulative process. There just was no time for the cumulativ…

A vast cloud of what gas and what dust? I thought we had started with only hydrogen and I thought that collapsing the hydrogen creates stars first. How could it even cut directly to the stage of black hole?

Re: Astronomers discover Milky Way’s biggest stellar black hole

#79

Post by konstantinua00 »

Etheryte wrote: post #63
konstantinua00 wrote: post #59

Earlier quoted context omitted.

would you say the same for "33 times longer"? that ut means "34 times the length"? for me "more X" and "Xer" are the same thing, so I don't get your system

Considering fractions might help you understand where he's coming from. If you say something is "0.5 times as long as a one meter thing" you would expect it to be 0.5 meters, but if it's "0.5 times longer than a one meter thing", you would expect it to be 1.5 meters. The same logic applies when you ditch fractions and use integers.

0.5 times longer is nonsense

0.5 times shorter makes sense

Post reply on HN