# So..um...what if the Large Hadron Collider does create a tiny black hole **URL:** \ **Category:** Factual Questions\ **Created:** [August 30, 2009, 4:16am UTC](https://boards.straightdope.com/t/so-um-what-if-the-large-hadron-collider-does-create-a-tiny-black-hole/508231 "2009-08-30T04:16:34Z")\ **Posts on this page:** 7\ **Page:** 4
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 31, 2009, 8:00pm UTC](https://boards.straightdope.com/t/so-um-what-if-the-large-hadron-collider-does-create-a-tiny-black-hole/508231/61 "2009-08-31T20:00:16Z")
That was a long post-- I started before **Alex** ’s latest. Yes, Hawking radiation is an entropy-increasing process (in fact this is one way of deriving Hawking radiation), and anything falling into a black hole is very much emphatically an entropy-increasing process. So yes, a tiny black hole would indeed be quite the energy source. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [August 31, 2009, 8:28pm UTC](https://boards.straightdope.com/t/so-um-what-if-the-large-hadron-collider-does-create-a-tiny-black-hole/508231/62 "2009-08-31T20:28:17Z")
> [@Chronos](#): > > That was a long post-- I started before **Alex** ’s latest. Yes, Hawking radiation is an entropy-increasing process (in fact this is one way of deriving Hawking radiation), and anything falling into a black hole is very much emphatically an entropy-increasing process. So yes, a tiny black hole would indeed be quite the energy source. I take it thats from it spewing out the energy that was required to make it in the first place and NOT energy you can get from dropping things into it? Because as I posted above, for a lab massed black hole, I can’t see how you can get any appreciable energy from just dropping matter into it. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [August 31, 2009, 8:49pm UTC](https://boards.straightdope.com/t/so-um-what-if-the-large-hadron-collider-does-create-a-tiny-black-hole/508231/63 "2009-08-31T20:49:43Z")
I got this from Wikipedia: > [@](#): > > On the other hand if a black hole is very small, the radiation effects are expected to become very strong. Even a black hole that is heavy compared to a human would evaporate in an instant. A black hole the weight of a car would only take a nanosecond to evaporate, during which time it would briefly have a luminosity more than 200 times that of the sun. Basicaly according to the article, I would need to create a black hole out of the Moon for it to be stable enough to use. And I just don’t have room for the Moon anywhere. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 31, 2009, 8:55pm UTC](https://boards.straightdope.com/t/so-um-what-if-the-large-hadron-collider-does-create-a-tiny-black-hole/508231/64 "2009-08-31T20:55:46Z")
> [@](#): > > Because as I posted above, for a lab massed black hole, I can’t see how you can get any appreciable energy from just dropping matter into it. If you can feed it quickly enough before it evaporates, it’s straightforward to turn a small black hole into a larger one. Just throw in matter at the same rate as it’s evaporating, and you’ve effectively got a matter-to-energy converter. Alternately, even without Hawking radiation, you can get gravitational potential energy from things falling into a black hole. This isn’t completely efficient, but you can get energy equivalent to half the infalling object’s mass from the change in potential energy, which is still a heck of a lot of energy. This works with any size of hole whatsoever, and is basically the power source behind quasars. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [August 31, 2009, 9:03pm UTC](https://boards.straightdope.com/t/so-um-what-if-the-large-hadron-collider-does-create-a-tiny-black-hole/508231/65 "2009-08-31T21:03:51Z")
> [@Chronos](#): > > If you can feed it quickly enough before it evaporates, it’s straightforward to turn a small black hole into a larger one. Just throw in matter at the same rate as it’s evaporating, and you’ve effectively got a matter-to-energy converter. > > Alternately, even without Hawking radiation, you can get gravitational potential energy from things falling into a black hole. This isn’t completely efficient, but you can get energy equivalent to half the infalling object’s mass from the change in potential energy, which is still a heck of a lot of energy. This works with any size of hole whatsoever, and is basically the power source behind quasars. If it converts matter to energy directly I can see that, though if its spewing very high energy particles those arent particularly useful or convienient. And again, as I mentioned above, the gravitational energy is nearly a non starter IMO for tiny black holes. My WAG without cals is things like quasars and such work gravitationally because you have massive amounts of material dropping LONG distances towards something with an intense gravitational field, which again, non of which offhand appear to me to apply to a lab massed black hole. Oh, and I am perfectly willing to enterain the notion that small holes dont evaporate…or at least not as simply as we have discussed so far…because if there is any thing/place where what we dont really know about quantum gravity, quantized space and time starts to show (and anything else for that matter) a tiny black hole is probably it. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [September 2, 2009, 2:40am UTC](https://boards.straightdope.com/t/so-um-what-if-the-large-hadron-collider-does-create-a-tiny-black-hole/508231/66 "2009-09-02T02:40:16Z")
> [@billfish678](#): > > Oh, and I am perfectly willing to enterain the notion that small holes dont evaporate…or at least not as simply as we have discussed so far…because if there is any thing/place where what we dont really know about quantum gravity, quantized space and time starts to show (and anything else for that matter) a tiny black hole is probably it. OTOH, it seems to me that shouldn’t be that easy to accidently annihilate a planet. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 2, 2009, 5:33pm UTC](https://boards.straightdope.com/t/so-um-what-if-the-large-hadron-collider-does-create-a-tiny-black-hole/508231/67 "2009-09-02T17:33:52Z")
Yes, a smaller black hole has less mass than a larger one, but on the other hand, you can also get much closer to a small black hole before falling in. The two effects balance out such that you really do get the same potential energy change falling into a black hole of any size. Now, with a larger black hole, you can feed it more matter at once, so the total power will be greater for a large hole, but the efficiency will be the same. > [@](#): > > Oh, and I am perfectly willing to enterain the notion that small holes dont evaporate…or at least not as simply as we have discussed so far…because if there is any thing/place where what we dont really know about quantum gravity, quantized space and time starts to show (and anything else for that matter) a tiny black hole is probably it. Certainly; nobody really knows how microscopic black holes behave, and we can be absolutely certain that we can’t just extrapolate how Hawking radiation works down to those levels-- Somewhere around the Planck mass, the conventional Hawking radiation calculations would say that the hole is emitting particles more massive than itself. It could be that such black holes really do become stable, due to some quantum-gravitational process we don’t understand yet. [Previous page](https://boards.straightdope.com/t/so-um-what-if-the-large-hadron-collider-does-create-a-tiny-black-hole/508231.md?page=3)