
How bad would it be if we accidentally made a black hole? - ColinWright
http://www.askamathematician.com/2015/11/q-how-bad-would-it-be-if-we-accidentally-made-a-black-hole/
======
evanpw
Related article: [http://phys.org/news/2011-05-mini-black-holes-atoms-
earth.ht...](http://phys.org/news/2011-05-mini-black-holes-atoms-earth.html)

TL/DR:

1\. Tiny black holes as a dark matter candidate; hundreds might pass through
the earth every year

2\. Difficult but not impossible to detect a black hole of 100 thousand kg
passing through the earth

3\. A black hole with a mass of 10 million kg at the center of the Earth would
take 10^13 years to absorb the planet -- much longer than Earth will survive
anyway

~~~
platz
"according to this theory"

~~~
nitrogen
One cannot accept the parts of established theory that say black holes of a
certain size might exist without also accepting the remaining parts that say
what a black hole of that size can and cannot do. It's like accepting science
enough to believe in cosmological constants, but not accepting science's
measurements of those constants.

~~~
ars
> One cannot accept the parts of established theory that say black holes of a
> certain size might exist without also accepting the remaining parts that say
> what a black hole of that size can and cannot do.

That is 100% not true. We don't know what a black hole will do, we just guess.
Until we actually measure one we have no idea if there are surprises we have
not thought about - or that we simply did not have any way to know were
possible since such an environment does not exist on earth.

> It's like accepting science enough to believe in cosmological constants, but
> not accepting science's measurements of those constants.

Is there something wrong with doing that? You have no idea if (for example)
those constants are actually constant. You have no idea if those constants
vary based on some local environment. Perhaps even based on some other
constant that we don't even know exists because we have never been able to
measure things any other way.

There are a TREMENDOUS number of assumptions baked into theories. And we try
to test as many of those assumptions as possible all the time, but there could
be assumptions we did not even realize we were making.

You should _really_ look into the history of science - it will give you some
humility. At _every_ age we thought we were at the pinnacle of science, only
for later generations to find out things we never realized.

There is no reason whatsoever to expect this generation to be any different.

~~~
nitrogen
_We don 't know what a black hole will do, we just guess._

Normally I don't ask this sort of question, but are you a practicing
physicist? If you are then this point is irrelevant. But if not, then we're
all laymen/women here, and it's silly to accept the mathematical "guess" that
says there might be tiny black holes but reject the proposed properties, when
the same math that postulates their existence describes their likely
properties.

 _You should really look into the history of science - it will give you some
humility. At every age we thought we were at the pinnacle of science, only for
later generations to find out things we never realized._

No doubt. I'm not questioning that. I'm saying it's presumptuous to pick and
choose elements of a hypothesis without understanding the math behind it. If
any of the participants in this thread are qualified to do so (clearly I am
not), I'd love a link to your work on black holes. Otherwise, I maintain my
original position.

~~~
ars
The math for hawking radiation is far less accepted than the math for black
holes. You are making a mistake by giving them equal weight.

Not that the math for black holes is all that well accepted in the first place
- there are many holes in the math that quite clearly scream "we don't really
know". For example a charged, or rapidly spinning singularity might be "naked"
which breaks all theories and clearly shows how little we know about black
holes.

> but reject the proposed properties, when the same math that postulates their
> existence describes their likely properties.

That isn't true though. It's completely different math. And Hawking radiation
has a large information theory hole which tells us to be cautious - there is a
gap in the theory, we don't actually know what will happen.

Remember neither of these theories have ever been observed, it's all math and
simulations, no observations. (Super massive objects have been observed, but
not event horizons.)

~~~
mamon
> Hawking radiation has a large information theory hole

If you are referring to the fact that radiation brings back information from
the inside of the black hole, which undermines notion of black hole being
"event horizon", then there is one proposal to close this hole (it had been
even submitted to HN recently): computational complexity.

From what I understood this means that while in principle radiation leaks
information from inside of the black hole, the computational effort needed to
put that information together in its original form is too big to be possible
to do in practice (at least before thermodynamical death of universe).

------
shasta
The article makes it sound like a black hole with the mass of Everest wouldn't
be scary, since it would only have strong attractive force within a few
meters. But wouldn't it fall to the center of the earth, absorbing anything in
its way and then wouldn't the earth fall into it? Seems like its lack of
strength at a few meters isn't what makes it not-scary.

~~~
SeanDav
In theory, small black holes should kill themselves almost immediately, but
this aside - I find the argument that a small black hole is not dangerous
because you have to get really close to it - not a valid argument (as a
layman!). Assuming the black hole did not destroy itself and was big enough to
attract nearby molecules and atoms, it would suck in all the molecules nearby
in an endless stream, getting bigger and bigger and accelerating its growth,
until it consumed the earth.

~~~
pcl
I had the same thought. If the black hole were formed lived long enough to
fall to the floor of whatever lab it was created in, it'd presumably basically
bore its way to the center of the Earth, aggregating matter (and thus mass) as
it went.

When it reached the center, I'd expect that its gravity well would pull the
rest of Earth into the black hole, unless it somehow found itself in a vacuum
large enough to not create a gravity well. That would presumably be a sphere
the radius of the amount of core material that is equivalent to the mass of Mt
Everest, plus whatever it accreted on its descent.

So really, the question is whether or not a black hole that we could create
would be able to make it to the floor of the lab... the article sorta touches
on this:

 _The gravitational pull of a few micrograms of matter, regardless of how it
is arranged, is never dangerous; you wouldn’t get pulled inside out if you ate
it. However, you wouldn’t get the chance, since any black hole that we could
reasonably create would already be mid-explosion._

~~~
pdonis
_> If the black hole were formed lived long enough to fall to the floor of
whatever lab it was created in_

Since the proposed method of creating the hole is to collide particles in an
accelerator, we would expect the hole, when formed, to be moving the way
particles created in an accelerator move, i.e., at close to the speed of
light. So the hole would fly off into space, since it would be moving much,
much faster than escape velocity. (Also, as the article notes, the hole would
explode due to Hawking radiation soon after it was created.)

 _> unless it somehow found itself in a vacuum large enough to not create a
gravity well_

Not sure what you mean by this. The "gravity well" of the hole is the same
whether it's surrounded by vacuum or matter. The only difference is what can
possibly fall in.

~~~
knodi123
> to be moving the way particles created in an accelerator move, i.e., at
> close to the speed of light.

Not quite. The proposed method involves rotating two [sets of] particles in
opposite directions, and then ramming them together. Yes, both sets of
particles have super-high velocities- but if they were rammed together, the
resulting _net_ velocity should be zero-ish (plus or minus experimental
error).

~~~
pdonis
_> if they were rammed together, the resulting net velocity should be zero-ish
(plus or minus experimental error)._

Not necessarily. This is how current accelerator experiments work, and the
particles coming out of those do not have zero velocity.

However, it is true that there is a key difference between current experiments
and a hypothetical experiment that forms a black hole. The rest mass of the
particles formed in current experiments is fixed, so any energy pumped into
the particles over and above that becomes kinetic energy. But the rest mass of
a black hole is not fixed, so it would be possible for all of the energy
pumped in to become rest mass of the hole, instead of kinetic energy.
(Possible, but still not guaranteed, as far as I can see; but since nobody
really has a detailed theory of how all this would work, it's all speculation
anyway.)

------
idlewords
The article briefly mentions the large amount of energy stored in the collider
beams. In the LHC, "each unimpeded beam is capable of melting a 500-kilogram
block of copper." This energy has to be dissipated in a few microseconds if
something goes wrong in the collider. For the LHC, the solution is to heat a
huge graphite cylinder to over 700 C.

Not as cool as a black hole, but a pretty neat engineering challenge.

[http://spectrum.ieee.org/aerospace/astrophysics/cern-to-
star...](http://spectrum.ieee.org/aerospace/astrophysics/cern-to-start-up-the-
large-hadron-collider-now-heres-how-it-plans-to-stop-it)

~~~
SeanDav
Very interesting - I wonder why they did not choose to run the beam through
water to dissipate energy?

~~~
idlewords
There's a technical discussion of using graphite vs. aluminum vs. copper in
this paper:
[http://flash.desy.de/sites2009/site_vuvfel/content/e403/e164...](http://flash.desy.de/sites2009/site_vuvfel/content/e403/e1642/e1132/e1129/infoboxContent1791/fel2006-05.pdf)

And a comparison of graphite vs. water schemes here:
[http://tesla.desy.de/new_pages/TESLA_Reports/2001/pdf_files/...](http://tesla.desy.de/new_pages/TESLA_Reports/2001/pdf_files/tesla2001-04.pdf)

~~~
SeanDav
Thanks for the links. I note that the graphite vs water scheme paper actually
concludes that water cooling would be the preferred method.

------
tdurden
related: [http://news.sciencemag.org/europe/2015/08/tiny-black-
holes-c...](http://news.sciencemag.org/europe/2015/08/tiny-black-holes-could-
trigger-collapse-universe-except-they-dont)

------
Havoc
Beyond a certain level of screw-up there isn't anyone around to care anyway.

~~~
maaku
That's not a reason not to care in advance of trying something dangerous...

------
yongjik
Tangentially related: Thorne–Żytkow object
[https://en.wikipedia.org/wiki/Thorne%E2%80%93%C5%BBytkow_obj...](https://en.wikipedia.org/wiki/Thorne%E2%80%93%C5%BBytkow_object)

A hypothetical red giant that swallowed a neutron star, which sinks into the
center and replaces the giant's core. Even at such a scale, the star is
relatively stable (i.e., it doesn't go all kaboom immediately) because the
matter falling into the neutron core is heated to such a degree that it can
balance the inward pressure from gravity.

~~~
bitwize
> (i.e., it doesn't go all kaboom immediately)

Now I'm imagining astronomers going "Where's the kaboom? There was supposed to
be a star-shattering kaboom!"

------
dclowd9901
So when a black hole collapses, it explodes? I don't think I really understand
a black hole's lifecycle.

------
phaemon
Another concern with CERN's activities:

[http://www.askamathematician.com/2012/04/q-will-cern-
awaken-...](http://www.askamathematician.com/2012/04/q-will-cern-awaken-the-
elder-gods/)

------
EvanAnderson
Am I the only one who finds the photo of the spillway intake off-putting?

------
kr4
There are no true black holes [0] as researched done by Scientist Abhas Mitra
and his colleagues.

>>> Astronomers have certainly discovered thousands of massive compact
objects, which are considered as black hole candidates. In a strict sense, no
one can detect a black hole as "not even light can escape" from it. They are
at the best quasi-black holes. My research (Journal Mathematical Physics,
2009) has shown that true black holes have zero (gravitational mass) which
means their positive mass-energy is neutralized by negative gravitational
interaction energy . Thus no massive body can be a true black hole. In
addition, my parallel research has independently corroborated this fact that
true black holes have M=0! And such M=0 black holes can form only
asymptotically, implying they never quite form. And only approximate and
quasi-black holes can be formed.

Some reports say NASA has confirmed your idea that the so-called black holes
are balls of fire. But you say that's not exactly ...

Yes. The NASA report does not mention my research and admits that `Black Holes
are not Black Holes'. But the NASA research certainly bolsters my findings
because eruption of corona from a black hole is not understood, as admitted in
the NASA report. On the other hand, it gets most naturally explained by the
MECO paradigm by which the socalled black holes are balls of ultra-magnetized
fire (plasma) -something like the Sun.

My research has shown that there cannot be any true black hole. It is just a
point and all vacuum with an imaginary boundary Event Horizon from which even
light cannot escape. So if the corona (charged particles) have been inferred
to be ejected from Black Hole, it means it is not a true Black Hole as claimed
in 15 peer reviewed papers by me and collaborators. We also showed that as a
star would get hotter and hotter during Black Hole formation, there will be a
stage when the radiation pressure of the star material would counter the pull
of gravity. This is a quasi-static state and the hot star material would be
plasma.

What's your take on Stephen Hawking? Hawking has been trying to resolve Black
Hole Information Paradox (created by himself in 1976). Failing to do so, from
2004, he has been making noises that "there may not be exact EH" (2004), and
"there cannot be any true black hole " (2014) from some vague Quantum Gravity
argument which nobody understands, not even those who believe in black holes .
In contrast, my proof is exact, comple te and supported by observations, and
based on simple general relativity, no unspecified quantum gravity nonsense.
Many Nobel laureates too have been struggling to resolve this paradox, but
they want to keep black holes alive. Nobody wants to kill the goose, which has
been laying golden eggs. In contrast, only my research resolves it
meaningfully , by showing there is no black hole, no EH. Hence, there is no
paradox in the first place. You see, black hole is one of the biggest physics
paradigms for almost 100 years with thousands of celebrity professors,
researchers, Nobel Laureates having personal stake. Who would like to set
their own Lanka on fire? <<<

0: [http://timesofindia.indiatimes.com/home/science/There-are-
no...](http://timesofindia.indiatimes.com/home/science/There-are-no-true-
black-holes-Scientist-Abhas-Mitra/articleshow/49966468.cms)

------
rfjedwards
Whew!

