
Astronomers find an ancient black hole the size of 12B suns - grej
http://www.washingtonpost.com/news/speaking-of-science/wp/2015/02/25/astronomers-find-a-shockingly-ancient-black-hole-the-size-of-12-billion-suns/
======
antognini
To put this result in context, an important open question in astronomy is how
supermassive black holes are formed. There are currently two viable formation
mechanisms:

1\. The bottom-up model: After the first generation of star formation, the
most massive stars formed black holes with masses somewhere between 10-100
solar masses. These then began accreting material and merging with each other
and gradually grew into the supermassive black holes we see today.

2\. The direct collapse model: As galaxies were forming, there was generally a
concentration of gas at the bottom of each galaxy's potential well. If this
cloud were dense enough, under the right conditions it could collapse directly
into a ~10^4-10^6 solar mass black hole without fragmenting into individual
stars.

The bottom-up model has historically been considered more plausible because
the physics involved is better understood. However, discoveries of very
massive black holes very early in the lifetime of the universe are starting to
pose very serious challenges for this model. The reason is that black holes
cannot grow arbitrarily rapidly. The rate at which a black hole can accrete
matter is limited by the "Eddington accretion rate" or the "Eddington limit."
Above the Eddington limit the gas gets so hot as it accretes onto the black
hole that radiation from the infalling gas blows away the rest of the gas.
(There are many details in this process which I have glossed over, but suffice
to say it's generally difficult to get an accretion rate that is much more
than this limit.)

If you start out with a black hole with a mass of ~100 solar masses and you
feed it constantly at the Eddington limit, you can just barely grow black
holes large enough to power the quasars we see in the early universe. But as
more distant and more massive black holes are discovered, it gets harder and
harder to grow a stellar mass black hole into a supermassive black hole in the
age that the universe has existed at that time, and you have to invoke
mechanisms like super-Eddington accretion and black hole mergers to grow a
large enough black hole. This may be possible for individual black holes, but
the more fine-tuned the model becomes, the less likely it is to be the primary
channel by which supermassive black holes form. These sorts of discoveries are
therefore providing evidence that the simple bottom-up picture may not be
correct and either super-Eddington accretion, mergers, or direct collapse is
necessary to form these black holes.

~~~
ars
> black hole mergers

Black holes can not merge - time dilation means it would take an infinite
amount of time for them to do so.

~~~
simonh
It would only be infinite for someone in or near the black hole. Not for an
observer at a distance.

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beastman82
Things like this make me very skeptical that the accepted model is correct.

~~~
privong
> Things like this make me very skeptical that the accepted model is correct.

To which "accepted model" are you referring – the cosmological model for the
Universe, the determination of black hole masses, the formation and growth of
supermassive black holes, or something else? As @nilkn notes, this discovery
is in conflict with existing models of the formation and growth of (some)
supermassive black holes, which is a reason this paper is in Nature.

~~~
kordless
I'll say it. We're running in a virtual machine. There.

~~~
colechristensen
[http://en.wikipedia.org/wiki/Holographic_principle](http://en.wikipedia.org/wiki/Holographic_principle)

~~~
cocoablazing
The usefulness of the HP is principally in the application of the aDS/cft
duality to otherwise intractable calculations. It doesn't have anything to do
with the universe being virtual or computable. Perhaps you are thinking of
[https://en.wikipedia.org/wiki/Digital_physics](https://en.wikipedia.org/wiki/Digital_physics).

------
oafitupa
We already knew about several black holes more massive than that though (the
news seems to be about how ancient it is too, not just its mass):

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

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AshFurrow
_Mass_ , not size. Come on, this is basic astrophysics!

~~~
semaphoreP
Technically, the radius of a black hole is uniquely determined by its mass, so
one can construct a unit system where mass and radius use the same unit of
measure...

~~~
hamoid
That unit system might allow comparing black holes to other black holes. But
our sun does not have the same density as a black hole, or? The nature article
[1] does not compare it to the size of our sun, but to its mass.

[1]
[http://www.nature.com/nature/journal/v518/n7540/full/nature1...](http://www.nature.com/nature/journal/v518/n7540/full/nature14241.html)

~~~
semaphoreP
Actually, you can use this unit system (called Geometrized units [1]) for
anything, but it is especially convenient for describing black holes and
general relativity in general. As a rule of thumb, in the geometrized units, 1
solar mass = ~1.5 km = ~5 microseconds. They have the same units so you can
use them interchangeably (Our sun weights 5 microseconds).

I'm just being pedantic here obviously..

[1]
[http://en.wikipedia.org/wiki/Geometrized_unit_system](http://en.wikipedia.org/wiki/Geometrized_unit_system)

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venomsnake
Probably stupid question, but do we have solid evidence that the laws of
physics/constants were the same/behaved the same back then? I know that to be
true for the last couple of billion years. But so early in the development of
the universe?

~~~
tim333
You can get evidence by observing the early universe with telescopes and the
like. I don't think anyone has observed the laws/constants being noticeably
different although you can't really prove a negative.

~~~
privong
You can put limits on how much they could have changed, though. And people do
this, e.g., [0], which found the proton-to-electron mass ratio has not varied
by more than a relative factor of 4e-7, over the past 7.5 billion years.

[0] [http://arxiv.org/abs/1412.7757](http://arxiv.org/abs/1412.7757)

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mrng
Arxiv paper, with more relevant (albeit highly specialized) information than
Nature's abstract:

[http://arxiv.org/pdf/1410.2689.pdf](http://arxiv.org/pdf/1410.2689.pdf)

~~~
privong
That is not the same paper. The preprint you linked was published in the
Astrophysical Journal Letters, and discusses a different quasar (SDSS
J013127.34-032100.1, at a redshift of z=2.5). The Nature paper is about SDSS
J010013.02+280225.8, at redshift z = 6.30. The author list is similar, so it
is likely the same team. But the arxiv link is a different discovery.

~~~
privong
I made a typo: the linked paper in the parent comment to mine is about an
object at redshift z=5.18, not z=2.5.

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zhyder
Did the big bang and immediate expansion necessarily distribute matter
uniformly? If not, couldn't this just be the dumb luck of this black hole that
it started its life itself with many solar masses, so it didn't need to
accrete as much in the next 900 million years?

~~~
simonh
The idea is that the incredibly fast inflation immediately following the big
bang smeared out the mass and energy of the universe very thinly, so that any
unevenness got flattened out.

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i2i
I love the timing of this with the release of a new/old theory that the
universe has always existed :

[http://zeenews.india.com/news/space/no-big-bang-new-
theory-s...](http://zeenews.india.com/news/space/no-big-bang-new-theory-
suggests-universe-always-existed_1544948.html)

This would make the age of the this black hole less of a mystery.

I always new that there was a relationship between black holes and quasars
(In/Out) but was unaware that there was an established relationship between
specific events. Does anyone have links to this ?

~~~
wozniacki
Cosmology from quantum potential ( Ahmed Farag Ali, Saurya Das )

    
    
      It was shown recently that replacing classical geodesics 
      with quantal (Bohmian) trajectories gives rise to a
      quantum corrected Raychaudhuri equation (QRE). In this 
      article we derive the second order Friedmann equations
      from the QRE, and show that this also contains a couple
      of quantum correction terms, the first of which can be
      interpreted as cosmological constant (and gives a correct
      estimate of its observed value), while the second as a
      radiation term in the early universe, which gets rid of
      the big-bang singularity and predicts an infinite age of
      our universe. [1]
    

[1]
[http://arxiv.org/pdf/1404.3093v3.pdf](http://arxiv.org/pdf/1404.3093v3.pdf)

~~~
saiya-jin
If universe is older than big bang, why don't we see anything older than that?
I mean, there isnt such a drop in visibility of galaxy/bright object that is 5
billion vs 10 bilion years old. So, where are all 30 or more billion year old
objects? Maybe there wasn't ultimate singularity in the beginning, but
universe is definitely not the same no matter how far you look in the past.

~~~
ccozan
I think the answer is here [1].

[1]
[http://en.wikipedia.org/wiki/Observable_universe#Misconcepti...](http://en.wikipedia.org/wiki/Observable_universe#Misconceptions_on_its_size)

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scotty79
What if it was two supermassive blackholes rotating around center of mass?
Could we tell the difference?

Wouldn't time around them be slowed so much that it would look like they don't
move at all?

~~~
amelius
The term to search for would be "supermassive black hole binaries".
Apparently, these systems have a characteristic fingerprint.

[http://arstechnica.com/science/2015/01/supermassive-black-
ho...](http://arstechnica.com/science/2015/01/supermassive-black-hole-binary-
discovered/)

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BAMartelly
How Douglas-Adams funny would it be if the mega black hole had somehow been
created by someone spilling their coffee on a keyboard at the CERN LHC

~~~
fit2rule
11.

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Lerc
>420 trillion times more luminous than our sun

So that would have a Habitable zone? How far away and how large?

~~~
nitrogen
Ignoring all other considerations, one could produce a distance using the
inverse square law.

~~~
Retra
Would that just mean taking the square root of the luminosity and interpreting
it as distance in AUs?

~~~
Lerc
So...
[https://www.google.com/search?q=sqrt%28420*10^12%29au+in+lig...](https://www.google.com/search?q=sqrt%28420*10^12%29au+in+light+years)

324 lightyears.

Assuming Sol habitable is 0.7 to 1.2au the translated would be 227 to 389. A
shell of thickness approximately 160 light years where everything is in the
habitable zone (as long as it is not too close to another heat source)

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PinnBrain
Can we see it with less than a million bucks (or a trip to Wyoming)?

~~~
GigabyteCoin
>It was even detectable with a relatively small telescope, though researchers
in China did have to ask for help from astronomers in Chile and the United
States to get a higher-resolution look.

~~~
keypusher
I have a feeling that "relatively small" telescopes which find new black holes
to publish in Nature are still quite expensive by normal person standards.

