
Possible detection of a black hole with a mass that was thought to be impossible - theafh
https://www.quantamagazine.org/possible-detection-of-a-black-hole-so-big-it-should-not-exist-20190828/
======
pavel_lishin
> _(The million- and billion-solar-mass supermassive black holes that anchor
> galaxies’ centers formed differently, and rather mysteriously, in the early
> universe. LIGO and Virgo are not mechanically capable of detecting the
> collisions of supermassive black holes.)_

Is this because those collisions would be too "loud", in the same way that I
wouldn't expect my microphone to be able to pick up an earthquake?

~~~
jessriedel
Supermassive black holes are larger, so the characteristic timescale of their
dynamics is longer, and the gravitational waves generated by their merger are
correspondingly of lower frequency. More specifically, supermassive black
holes binary (SMBHB) mergers usually ring at 0.1-1 millihertz, whereas LIGO's
sensitivity is concentrated around more like 0.1-1 kilohertz, a typical
frequency of stellar-mass black holes binary mergers. The ~6 orders of
magnitude difference comes directly from the fact that supermassive black
holes typically weigh in at millions of stellar masses.

See the plot here:

[http://www.tapir.caltech.edu/~teviet/Waves/gwave_spectrum.ht...](http://www.tapir.caltech.edu/~teviet/Waves/gwave_spectrum.html)

(To convert from wavelength (meters) to frequency (hertz), take the speed of
light and divide it by the wavelength.)

~~~
lugg
So it's like how you can easily see a small swell from a small boat but a
larger swell can be almost undetectable.

Is this also why we don't just get ripped apart during one of these ripple
events which are probably all around us as gravitational noise?

I wonder if this is why seemingly tiny vessels can cross large oceans just as
easily as larger ones.

~~~
MrEldritch
The reason we don't get "ripped apart" during these ripple events is simply
that spacetime is so _stiff_ that even absolutely monstrous amounts of
gravitational energy lead to only the tiniest distortions in spacetime
geometry. A black-hole collision may put out more power in gravitational waves
than the entire optical luminosity of the visible universe, and the result
when it reaches us will result in a distortion of less than the diameter of a
proton.

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tehsauce
"LIGO and Virgo are not mechanically capable of detecting the collisions of
supermassive black holes"

Anyone have ideas why this might be?

~~~
skykooler
The larger black holes have a lower frequency chirp. Supermassive black holes
would produce a peak frequency so low it gets filtered out as noise.

~~~
ISL
It isn't filtered out as noise, but rather drowned out _by_ noise.

See Figure 5a:
[https://arxiv.org/pdf/1604.00439.pdf](https://arxiv.org/pdf/1604.00439.pdf)

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dsr_
Sgr A* is thought to be 4+ million solar masses.

GCIRS 13E, 3 ly away from Sag A*, is thought to be 1300 solar masses.

------
rc_kas
> But in 1967, three physicists at the Hebrew University in Jerusalem realized
> that when the core of a dying star is very heavy, it won’t gravitationally
> collapse into a black hole. Instead, the star will undergo a “pair-
> instability supernova,” an explosion that totally annihilates it in a matter
> of seconds, leaving nothing behind. “The star is completely dispersed into
> space,” the three physicists wrote.

Does this mean that maybe the big bang was just a unstable pair that did what
they describe?

~~~
NikolaeVarius
The big bang might as well be the almighty space chicken laying an egg for all
we care before the moment space-time became a concept worth talking about

~~~
jacobush
Sometimes referred to as "God". :)

~~~
earthscienceman
You know. I get why this is down-modded... but in the end it's actually a
beautifully succinct description of exactly why god is compelling to some
people.

(Obligatory, "as an atheist" disclaimer)

~~~
chousuke
As far as I can tell It's compelling because people tend to dislike
uncertainty and making up stories and hypotheticals can feel like knowing. I
don't have an issue with that per se, but the pretend "knowledge" tends to get
intertwined with all sorts of claims that actually matter, and that bothers
me.

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wtdata
This title is sensationalist.

Of course there are black holes with a lot more than 50 solar masses. It's
just that they aren't created in a single event by the death of a star.

[https://en.wikipedia.org/wiki/List_of_most_massive_black_hol...](https://en.wikipedia.org/wiki/List_of_most_massive_black_holes)

------
ajuc
They can't be created from stars 50-130 solar masses, but they can be still
created by joining 2 black holes of smaller masses, right?

The bet seems stupid when you consider black hole in center of Milky Way is
supposed to be 4 million times solar mass.

So the prediction was wrong.

~~~
Accujack
If you read the article, you'd find out that the supermassive black holes like
those at the center of our galaxy were formed very early in the Universe's
life, when the laws of physics were different.

~~~
Aardwolf
It's the same laws but at higher energy level.

Depends on how you look at it I guess? Would you say the laws of physics on
the moon are different because you can jump higher?

~~~
im3w1l
This "when the laws of physics were different" really pisses me off. It makes
it sound like gravity pushes you away and magic is real and stuff.

~~~
coldtea
QM has even stranger effects, so there's that...

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0xFFFE
So if I am understanding this correctly, lower threshold (in terms of mass)
for a star to become a black hole is lower than what was earlier thought?

------
cellular
In all these situations there are forces and other forces that resist original
force but under different ranges. It keeps the universe interesting!

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cheschire
Ah, the one Inigo dreamed of.

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brianberns
The title is misleading. Just to be clear, theory predicts that blacks holes
shouldn't be created between 50 and 130 solar masses, but there are plenty of
black holes >130 solar masses. This is just an observation of a black hole
that falls inside the supposedly "forbidden" range.

~~~
asdfman123
> This is just an observation of a black hole that falls inside the supposedly
> "forbidden" range.

So you're saying it's of a mass that was thought to be impossible?

~~~
brianberns
HN updated their title after I posted my comment. The title of the linked
article is still misleading: "Possible Detection of a Black Hole So Big It
‘Should Not Exist’".

~~~
homonculus1
That's so incredibly frustrating. I can't tell you how many times I've seen
this exact exchange when all it would take to prevent it is the slightest
indicator that the previous title got memory-holed. The other issue is when
you're looking for an article you saw earlier and can't find it. It's only a
minorly bewildering inconvenience but as a user it feels a slap in the face to
usability since it just isn't necessary.

I just saw in another thread that _the links themselves_ are mutable, i.e. you
could discuss one article and future readers of your comments saw a completely
different version of the story.

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Retric
Non clickbait headline: ‘Possible detection of Black Hole that grew after
formation.’

Honestly, I would have been more intrigued by the less clickbait headline for
novelty if nothing else.

~~~
Sargos
Maybe this works from your perspective but for everyone else who doesn't
immediately understand that "after formation" is something strange and not
normal the title helps people understand that this is an interesting and novel
topic and worth exploring more.

~~~
pmiller2
So, stars between 50-130 solar masses don’t directly form black holes because
they blow themselves apart at the end of their lives. I got that from the
article. Is the idea that a black hole less than 50 solar masses should
usually evaporate before it can gain enough mass to fall into that gap?

Edit: or is it just that there shouldn’t be enough around for a smaller black
hole to “eat” to become that big?

~~~
Retric
Black Hole evaporation is incredibly slow in the 1+ Solar Mass range (~2.1 *
10^67+ years).
[http://xaonon.dyndns.org/hawking/](http://xaonon.dyndns.org/hawking/)

Also, another astrophysics took the other side of the bet as a 50/50\. So, it
was not considered all that unlikely.

PS: There is normally a limit to how fast black holes can eat, but that’s
irrelevant when two black holes collide.

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Footkerchief
The accurate headline would be: "So Medium-Sized It Should Not Exist"

~~~
luxuryballs
There’s really no such thing as “should not exist”, only “this challenges our
assumptions”. Anything is possible, it might make the human mind uncomfortable
but it’s true. Our ability to comprehend and measure things is so unfathomably
finite that it’s almost laughable to think we can be sure of anything.

~~~
ASalazarMX
Or, hear me out, "The IMPOSSIBLE black hole that science can't explain".

~~~
s_dev
Thought to be impossible*

Title is fine -- this is great story. The media are notorious for often make a
hames of scientific reporting but this isn't too bad.

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_bxg1
> Systems programming is the development and management of software that
> serves as a platform for other software to be built upon.

What a wonderfully concise definition. I was never sure exactly where to draw
the line; "You know, it's, uh, programming where you have to manage memory.
They use C for it. It's lower-level, and stuff. It's operating systems but not
_just_ operating systems."

