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Stany asked about LHC BH creation

  1. Apr 12, 2010 #1
    Moved from locked thread. Stany asked:
    1: That was about creating mini black holes, not worm holes.

    2: Although the maths was not provably impossible, it is not yet clear whether mini-black holes can be created in practice except by evaporation from not-so-mini BHs which is a SLOOOOOW process, so slow as to be statistically implausible. (While waiting trillions of years for the evaporation of a large BH, a lot more stuff, including photons, would be practically sure to wander in!)

    3: The energies may sound impressive, but the LHC still is orders of magnitude short of the energy needed to compete with some not terribly rare cosmic ray particles. If LHC energies were sufficient to create planet-eating mini-BHs, there wouldn't be any planets left in our solar system, much less any sun! The far greater energies of cosmic particles that strike us in their umpteens every day, as they have been doing for probably over ten billion years 24/7, would otherwise have seen to that looooong ago! And the same goes for the rest of our observable universe, only more so. Every significant body keeps colliding with those cosmic projectiles.

    4: "10,000 nuclear bombs or something" amount to a buck in the droppet or something, a small buck in a huge droppet or something. We get earthquakes bigger than that. More energy gets released in a modest rain shower than from a Hiroshima bomb -- work it out! When you deal with matters of this nature, be very, very careful about messing with big-sounding numbers. In fact, be careful about dealing with numbers at all unless you have carefully worked out what they mean. Big numbers without meaning are like big shouting without saying anything: just a lot of noise. They make you sound silly instead of impressive.

    5: OK, so suppose you get a comet, planet, asteroid or something to hit us; a real dino-killer-PLUS! Problem solved? Not really, unless you count wiping out Earth as a solution. But, you say, what about all that energy? My maths says it is enough to create ummm... OK, maybe not a WH, if those spoilsports say you can't create worm holes, but surely a mini-BH. How about that NOW, Mr Smarty-pants party pooper?

    Sorry man, you still had better insure your parade against rain. Suppose your maths did say there was enough energy, more than a whole bucketful of cosmic particles, that won't cut it. Think of the LHC. What it does is, as someone put it, like shooting a couple of needles across the Atlantic and having them collide point first, and having them collide with a huge bang at that. That energy is really, really concentrated, right?

    Now think about a Pluto-sized projectile striking us at some unreasonably high speed, not just our escape velocity of some 12kps, but an implausible thousand times that: 12000kps!! that is 43200000kph, enough to get you from here to the sun before breakfast! Surely that is enough energy?

    Mebbe! (Or mebbe not) but lets look at some realities about energy. Suppose I take a hammer and fairly violently hit a nail with it at say, 10 mps, OK? Suppose the hammer weighs a kilo. Now I take a two-kilo pillow and really hit that nail for all I am worth, at say 20kph. Twice the speed and twice the mass. And yet, you know which of the two, hammer or pillow, hits harder. The pillow will hardly drive the nail (or squash your thumb) at all.

    But what does the maths say? 2X2=4? Twice as fast and twice the mass? Nope! The square of the velocity, remember? 2X4=8! Eight times the energy of the hammer, and all we achieve is to rip the pillow!

    So our incoming body, made of hard stuff at what, 43200000 kph, should have a huuuge amount of energy, really big numbers of ergs and yoctograms all over the place. Right?

    Certainly right! You got me there all right!

    But it would be spread out like a powder puff rather than a pillow compared to what you would need to create a mini-BH! Instead of firing two needles across the Atlantic, you would be firing the equivalent of two million-tonne marshmallows! (And probably missing each other at that!)

    So forget about miniBHs!

    As I said, without the numbers you are lost, but big numbers alone are not enough; you need to get the facts and the mechanics right as well. When you read big numbers in the papers or watch them on TV, remember that they have been filtered through the minds and the mouths of people who know less about it on average than you do, even though they make it sound very authoritative and impressive. Making it sound authoritative and impressive is their job.

    Your job is to filter out the nonsense, and that takes hard work. Is it worth the trouble?

    Not if you are happy to be the puppet that dances to their tune and pays them celeb wages.


    Last edited: Apr 12, 2010
  2. jcsd
  3. Apr 26, 2010 #2
    1. Our atmosphere is hit alot stronger than the two protons at the lhc, but in the lhc is the first time a collision will be observed in lab.
    2. Black hole pull depends on the mass, so a mass of two protons will be very low even if black hole is created.
    3. So there are stronger particle collisions every day and no black hole is created.
  4. Apr 27, 2010 #3
    Very good point! Just because there is an event horizon doesn't mean that much would be falling in!
    And the evaporation rate by Hawking radiation, of a black hole of such a size, assuming it were created at all, would be practically instantaneous.

    Gee, time to relax again! :biggrin:

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