So what's plan B if the LHC produces a black hole that doesn't go away?

[Half_Man_Half_Wit]

Pretty much all conceivable (and a great many pretty inconceivable) worries about the LHC are addressed in this thread; on the issue of micro black holes, I tried to sum up the arguments in this post.

[ZenBeam]

@si_blakely

.Because the rate of accretion would be so slow, relying initially (as it would) on subatomic collision, not gravitational accretion. Gravity is really that weak. Star consuming black holes (what everyone imagines a black hole is like) have many multiples of stellar mass - a MHC has a mass less than a proton. The above article calculates that that transition from sub-atomic to atomic effects for a MHC (with a velocity less than earths escape velocity in the earth) is of the order of a hundred billion years. And that is discounting charge effects (a MHC absorbing protons will accumulate a charge that repels other protons, making capture impossible). In a super-dense object (like a white dwarf) this transition time is much less, but we see white dwarfs, so this obviously does not occur. The very existence of observable large mass objects in the universe indicates that stable MHCs do not exist at all.

Si

A couple of questions. What does MHC stand for (I tried Googling)? And why is its mass necessarily less than a proton?

[si_blakely]

@ZenBeam

A couple of questions. What does MHC stand for (I tried Googling)? And why is its mass necessarily less than a proton?

Sorry - a typo for MBH -* Microscopic Black Hole*. Looks like I conflated MBH and LHC (Large Hadron Collider).

And it looks like I misremembered the mass of the MBH - it should be the Planck Mass, ~2x10[sup]-8[/sup] kg (~1TeV) - 9 orders of magnitude greater than that of a proton. This level of energy is not achieved in the LHC. It is possible that if string theory is correct, the Plank mass may be different due to wrapped higher dimensions accessible at LHC energy levels - but this is theoretical. But even if this is true, the capture radii of such a MBH is still vanishingly small, and relies on collision and not gravitational attraction in the initial subatomic phase of growth.

Si

[Half_Man_Half_Wit]

@si_blakely

And it looks like I misremembered the mass of the MBH - it should be the Planck Mass, ~2x10[sup]-8[/sup] kg (~1TeV) - 9 orders of magnitude greater than that of a proton.

I think you got this mixed up a bit – 210[sup]-8[/sup] kg ~ 1.2210[sup]19[/sup] GeV (10[sup]16[/sup] TeV), 19 orders of magnitude greater than that of the proton; but you’re correct in saying that those energies aren’t reached at the LHC, which will only go up to about 14 TeV, which would mean black holes of a few thousand proton masses, on the order of 10[sup]-24[/sup] kg.

[ZenBeam]

Ah. So MHC stands for Microscopic Hadron Collider. Well no wonder you can’t get anything bigger than a proton.

[SeanArenas]

@Malacandra

I remember a story called “The Gun That Shot Too Straight” - a kid scientist came up with this device that fired self-sustaining energy balls, about BB sized to begin with. They plinked the target nicely, chewed through the tree the target was tacked to, and disappeared into the ground, still tiny. Hours later, kid and uncle were watching TV when news reports came in of a RAAF fighter being narrowly missed by a mysterious fireball that shot out of the ocean and off into space. Uncle speculated who the thing might end up hitting, and when, and who would be shooting back.

It was published in Dragon and I’m about 90% certain I have that issue in my attic.

That’s the story I was talking about! When the balls came out, they disturbed some ship or another. I am pretty sure that I have the Dragon or the Polyhedron it was published in my closet, and if I wasn’t boarding a bus for Frisco in moments, I would probably dig it up!

[tullsterx]

@KneadToKnow

Sounds like the answer I keep giving my girlfriend to her question, “What would you do if you came home from work and I were here with another girl waiting for you?”

Ummm. . . and you don’t have a plan for that? I spend most of my idle time planning for hypothetical events like that.

[si_blakely]

@Half_Man_Half_Wit

I think you got this mixed up a bit – 210[sup]-8[/sup] kg ~ 1.2210[sup]19[/sup] GeV (10[sup]16[/sup] TeV), 19 orders of magnitude greater than that of the proton; but you’re correct in saying that those energies aren’t reached at the LHC, which will only go up to about 14 TeV, which would mean black holes of a few thousand proton masses, on the order of 10[sup]-24[/sup] kg.

You are probably right on the units conversion. The PDF linked above posits MBHs of ~1TeV (based on string theory affecting the Planck mass).

Si

[MysteryFellow63427]

I believe Hug Bot is relevant to this discussion.

[janesphasm]

Are there theoretic numbers on kinetic potential of a black hole? Or are most theories on black hole physics based on mathematics and probabilities other than traditional physics (i.e. quantum physics)?

[Bosstone]

@Cerowyn

There is often confusion when laymen try to interpret something outside of their expertise. If you ask a scientist working on the LHC “is there a chance that the experiment will create a black hole that will consume the earth,” it is perfectly accurate to answer “yes, there is a non-zero chance that that will happen.” However, virtually any question will have the same question, since quantum theory says that anything that can happen will (okay, it’s not quite that cut & dried, but that’s the essence of it). The trick, of course, is hanging around for an infinite amount of time to see it happening. If, however, you ask the question, “is it likely, even a little likely, that a black hole will be formed by the LHC,” the answer is an unqualified “no.”

There was a Daily Show piece last year, I think, where they interviewed some random Joe who believed there was a 50/50 chance the LHC would destroy us all. 50/50 because “either it will or it won’t.”

And this guy taught math and probability, as I recall.

[LilShieste]

@Bosstone

There was a Daily Show piece last year, I think, where they interviewed some random Joe who believed there was a 50/50 chance the LHC would destroy us all. 50/50 because “either it will or it won’t.”

And this guy taught math and probability, as I recall.

Here it is (actually from just last month).

[Bosstone]

@LilShieste

Here it is (actually from just last month).

Aha, thank you.

[Sapo]

@Bosstone

There was a Daily Show piece last year, I think, where they interviewed some random Joe who believed there was a 50/50 chance the LHC would destroy us all. 50/50 because “either it will or it won’t.”

And this guy taught math and probability, as I recall.

If that guy ever decides to run a lottery, please let me know. I like my odds of either winning it or not being 50/50.

[Chronos]

Quoth janesphasm:

Are there theoretic numbers on kinetic potential of a black hole? Or are most theories on black hole physics based on mathematics and probabilities other than traditional physics (i.e. quantum physics)?

First, I have no idea what you mean by “kinetic potential”. Second, quantum mechanics and general relativity are “traditional physics”, by now. Third, black holes are inherently the sort of thing that must be described by general relativity, and those produced at CERN, if any, would also be described by quantum mechanics, and things that are described by both GR and QM are not “traditional physics”, and in fact nobody knows how to describe them theoretically.

As for detecting microscopic black holes, the biggest telltale would be that the formation and subsequent decay of the hole would not respect most of the subatomic conservation laws (notably baryon number and lepton number). Lepton number can be explained away by neutrinos escaping unnoticed, but if we see a reaction where baryon number is not conserved, then we’ve either got microscopic black holes being formed, or something else that’s at least as interesting.

[Gfactor]

This is a zombie, but it seems pretty harmless, I’ll let it wander the streets until it gets hungry for brain.
**
Gfactor**
General Questions Moderator

[ChrisBooth12]

nuke it