Artificial Black Holes, again

[vanesch]

Their plan isn't to make just one or two, but rather thousands at a time.

The "plan" is not to make any black holes at all. Idle theorists have been looking for all kinds of weird speculations (because it's their job, and they don't have much experimental data on their hands for which there's no explanation yet) in the vague hope that they might be on something. Give them 30 more years and they'll come up with potential strawberry production in 42 dimensions
The only thing that the LHC will do is to smack protons together at about 10 times more energy than what has been done at the Tevatron at Fermilab for about 10 years or so.
In the most probable scenario, the only thing that will happen is Higgs production. In the next most probable scenario, supersymmetric particles might be found (and even this is totally speculative). All the rest is a wild guess.

Another issue; what's in it for us? Other than a "looky what we did", what value is this science to humanity?

It's a further test of some fundamental theories. Apart from the tremendeous technological spinoff resulting from the applied research by the experimentalists to make the machine and detectors up and running, there's not more utilitarian return than, say, a telescope or an astrophysics department or a visit to the moon. Nevertheless, don't underestimate the technological return by the experimentalists. It's big.

It seems to me that any effect that might be created at these energies is wholly impracticable for utilitarian applications. Or, if there might be a way to use these effects at lower energy levels, why not just build the lower energy technology and see if it works?

Lots of valuable resources expended, little likelyhood of benefit, possibility of doomsday destruction. Yeah... that sounds like a good plan!

Well MOST of the expended resources do not go to the PhD students looking at the data on their PC, but go into the applied R&D to build machine and detector. And *that* research has a lot of practical returns.

Let's for example not forget (as a VERY SMALL investment of some computer scientists thinking about a practical way to organize information dissemination within a collaboration) that it was at CERN that the WWW was invented (not "internet" as some erroneously claim). Talk about some return on investment !

 

[Quaoar]

I feel like I'm being ignored by the doomsday people here: Can the people who think the LHC is potentially dangerous explain to me why cosmic rays, which hit the atmosphere constantly at higher energies and with much greater frequency than the particles that will be produced at the LHC, haven't devoured the Earth yet?

Why is the Earth still here after 5 billion years of cosmic ray bombardment?

 

[SpaceTiger]

Hey, thanks, that was exactly my question in my previous post...

Sorry for not responding to you directly, vanesch. Pervect had pretty much made all the points I was going to bring up.

Okay, so let's say that it'd take 10 billion years for one nano black hole to eat the earth.

10 billion years is near the physical lower limit of what's possible (by the Eddington limit), but I wouldn't say it's probable.

How much time for 1,000 nano black holes? How about 100,000? A million?

Not much shorter. Remember, we're talking about exponential growth in the limiting case, so the limiting timescale will shrink only logarithmically with the number of black holes created.

It's also good to keep in mind all of the qualifications that go into these limiting calculations:

1. The black holes don't Hawking radiate away -- Given that a similar effect (the Casimir effect) has been experimentally confirmed, I don't think there's a great deal of skepticism about Hawking radiation in the physics community. Hawking radiation also lies within a regime in which most folks trust both GR and QFT.
2. The LHC would have to actually create black holes -- It's only a couple very exotic theories that predict any black hole creation at these laboratories. Mainstream theory predicts that we are a long way from the energy scale needed to create black holes (~10¹⁹ GeV).
3. The black holes would have to remain bound to the Earth -- This should only be the case with those created right at threshold, a small fraction of the total.
4. The black holes don't disappear upon interaction with other particles- - Since we don't have a reliable theory of quantum gravity, there's no reason to assume that micro black holes will stick around after creation.
5. The micro black holes will accrete rapidly -- Again, there's little we can do to address this question without QG.

If this is your idea of dangerous, then I think I should invest in your insurance provider.

 

[Jake]

Really? Is a theory that says that all terrestrial objects should spontaneuosly fly off the Earth as "possible" as a theory that says the previous theory is wrong.

Err, you seemed to have misunderstood me entirely. I was giving Hawking radiation more credence than it deserves, seeing that its been around for a lot less time than black hole theories in general, and therefore has had less time to be proven wrong. I was comparing specific theories not any theory. How you came to that conclusion is beyond me :)

And please explain to me where you came up with the numbers that it will take "10 billion billion billion" for a micro black hole to eat earth?

 

[Jake]

I feel like I'm being ignored by the doomsday people here: Can the people who think the LHC is potentially dangerous explain to me why cosmic rays, which hit the atmosphere constantly at higher energies and with much greater frequency than the particles that will be produced at the LHC, haven't devoured the Earth yet?

Why is the Earth still here after 5 billion years of cosmic ray bombardment?

It was stated earlier in this thread that those black holes, because they are so high energy and based on how they would be created, would be flung into space far away from earth.

 

[ubavontuba]

The sky is falling!

The "plan" is not to make any black holes at all.

Apparently, you didn't read my http://www.cerncourier.com/main/article/44/9/22", straight from the CERN Courier.

It's a further test of some fundamental theories. Apart from the tremendeous technological spinoff resulting from the applied research by the experimentalists to make the machine and detectors up and running, there's not more utilitarian return than, say, a telescope or an astrophysics department or a visit to the moon. Nevertheless, don't underestimate the technological return by the experimentalists. It's big.

That's one heck of an expensive microscope! Anyway, the experimentalists aren't really doing anything new, just bigger.

Well MOST of the expended resources do not go to the PhD students looking at the data on their PC, but go into the applied R&D to build machine and detector. And *that* research has a lot of practical returns.

Sorry, I just don't see it. The hardware is already well understood and has been duplicated (albeit at smaller scales) numerous times before.

Let's for example not forget (as a VERY SMALL investment of some computer scientists thinking about a practical way to organize information dissemination within a collaboration) that it was at CERN that the WWW was invented (not "internet" as some erroneously claim). Talk about some return on investment !

No, Al Gore invented the internet, haven't you heard?

 

[ubavontuba]

Run! Run for your lives! The sky is falling!

I feel like I'm being ignored by the doomsday people here: Can the people who think the LHC is potentially dangerous explain to me why cosmic rays, which hit the atmosphere constantly at higher energies and with much greater frequency than the particles that will be produced at the LHC, haven't devoured the Earth yet?

It's a matter of conservation of momentum. How fast are these particles moving relative to the earth? When they strike a particle, say of equal mass, how fast is the resulting mass moving? If the resulting mass is a nano black hole, what might stop it from passing clean through the earth?

If you want to state that subsequent collisions will stop it, I think you'd be quite frightened by how much mass it must then accrue in a very, very short time. They certainly ought to be detectable, as they pop up through the ground.

Why is the Earth still here after 5 billion years of cosmic ray bombardment?

Why is the fifth planetary orbit (the asteroid belt) a pile of loose rubble?

 

[Quaoar]

It was stated earlier in this thread that those black holes, because they are so high energy and based on how they would be created, would be flung into space far away from earth.

Point taken.

Here's a question for you: Almost all cosmic rays have interacted with many many particles before they hit our atmosphere. If creating black holes is so easy, why do we see cosmic rays at all? Shouldn't most of these high energy particles become black holes?

 

[vanesch]

It's a matter of conservation of momentum. How fast are these particles moving relative to the earth? When they strike a particle, say of equal mass, how fast is the resulting mass moving? If the resulting mass is a nano black hole, what might stop it from passing clean through the earth?

Well, the same argument can probably be applied to potential BH produced at LHC: they will have considerable momentum wrt the earth, because it is highly unlikely that the momentum balance of the remnants of the collision is perfect.

Why is the fifth planetary orbit (the asteroid belt) a pile of loose rubble?

I thought that the explanation was that the pull of nearby Jupiter disrupted planet formation... I didn't know it was due to an ancient civilisation having fired up their brand new particle accelerator

 

[vanesch]

Apparently, you didn't read my http://www.cerncourier.com/main/article/44/9/22", straight from the CERN Courier.

Yes, but that's highly hypothetical, no ? We already have to live in 10 dimensions...

Sorry, I just don't see it. The hardware is already well understood and has been duplicated (albeit at smaller scales) numerous times before.

The scaling up in itself needs a lot of R&D. You don't see this as spectacular breakthroughs, it are many many small improvements in the reliability of the production process and so on which make up the bulk of this research.

For instance, at PSI I remember having heard a talk about research on back-to-back connections between arrays of photodiodes on silicon and the ASIC that does the data selectioning and compression before sending it on an optical fibre. The industrially available techniques didn't have a high enough density of connection points to do this. So a lot of research was done to improve this, and the density was increased 16 fold.
Now that these back-to-back connections are available, the whole sandwich of photodiodes + electronics is used for high resolution medical X-ray imaging. It took 6-7 years of a 10 person R&D group to devellop this.

There are many such examples.

 

[tehno]

Wikipedia http://en.wikipedia.org/wiki/Micro_black_hole" that hawking radiation is a controversial theory which very well may not be true. Correct me if I'm wrong, but doesn't this mean that if we are able to create micro black holes at the Large Hadron Collider, and if Hawking radiation is wrong, we are effectivly destroying all of humanity and this entire solar system? Won't scientists at the collider try and create micro black holes? Isn't this a bit reckless on the part of the scientists to endanger all of human existence based on very theoretical science? All of this just to possibly learn a bit more about black holes. Doesn't make too much sense if you ask me...

I'm just trying to understand the thinking in all of this, thanks.

You don't have to try
That text seems like Star trek script writters' wild imagination gets out of control again

 

[AlphaNumeric]

It's a matter of conservation of momentum. How fast are these particles moving relative to the earth? When they strike a particle, say of equal mass, how fast is the resulting mass moving? If the resulting mass is a nano black hole, what might stop it from passing clean through the earth?

An electron hitting the upper atmosphere with energy E will have the same momentum as an electron in the LHC which has the same energy. The relative motion is taken into account when calculating collision energies, hence such concepts as "centre of momentum frame" or "centre of mass frame". Your point is zoid.

Why is the fifth planetary orbit (the asteroid belt) a pile of loose rubble?

Because of Jupiters gravity. If it was from a black hole, we wouldn't see most of the asteroids, they'd have been absorbed by the black hole.

 

[Gokul43201]

Err, you seemed to have misunderstood me entirely. I was giving Hawking radiation more credence than it deserves, seeing that its been around for a lot less time than black hole theories in general, and therefore has had less time to be proven wrong. I was comparing specific theories not any theory. How you came to that conclusion is beyond me :)

I was responding to what I perceived as a sweeping statement.

And please explain to me where you came up with the numbers that it will take "10 billion billion billion" for a micro black hole to eat earth?

The Cornell-Astronomy link provided by Pervect has an estimate of 10^28 years.

 

[ubavontuba]

Well, the same argument can probably be applied to potential BH produced at LHC: they will have considerable momentum wrt the earth, because it is highly unlikely that the momentum balance of the remnants of the collision is perfect.

In order for black holes to form (generally speaking) all of the energy must be expended in the collisions. Glancing blows, that allow for continued momentum of the particles, will not deliver enough energy to compress the particles into black holes. This is why they expect/hope only a small percentage of each run to form black holes.

I thought that the explanation was that the pull of nearby Jupiter disrupted planet formation... I didn't know it was due to an ancient civilisation having fired up their brand new particle accelerator

Jupiter wasn't always where it is. Besides, Jupiter's moons suffer more tidal forces than the asteroids, and yet there they are.

 

[ubavontuba]

An electron hitting the upper atmosphere with energy E will have the same momentum as an electron in the LHC which has the same energy. The relative motion is taken into account when calculating collision energies, hence such concepts as "centre of momentum frame" or "centre of mass frame". Your point is zoid.

Sure, but the relative motion frame of the two colliding particles is not the same as the relative motion frame of the earth, in this instance.

Because of Jupiters gravity. If it was from a black hole, we wouldn't see most of the asteroids, they'd have been absorbed by the black hole.

Not true, a rotating body eaten from within would collapse both outwardly and inward. It's a function of angular momentum (like Hawking radiation).

 

[ubavontuba]

Yes, but that's highly hypothetical, no ? We already have to live in 10 dimensions...

Maybe you didn't read my other http://news.bbc.co.uk/1/hi/sci/tech/4357613.stm" wherein it's claimed that they've already accomplished it.

The scaling up in itself needs a lot of R&D. You don't see this as spectacular breakthroughs, it are many many small improvements in the reliability of the production process and so on which make up the bulk of this research.

For instance, at PSI I remember having heard a talk about research on back-to-back connections between arrays of photodiodes on silicon and the ASIC that does the data selectioning and compression before sending it on an optical fibre. The industrially available techniques didn't have a high enough density of connection points to do this. So a lot of research was done to improve this, and the density was increased 16 fold.
Now that these back-to-back connections are available, the whole sandwich of photodiodes + electronics is used for high resolution medical X-ray imaging. It took 6-7 years of a 10 person R&D group to devellop this.

There are many such examples.

Sure... fine. But, wouldn't it have been a lot cheaper to just tell these same engineers that we want this or that for other applications? Why not just put them to work building better medical imagers, rather than having to develop the technology secondhand?

 

[vanesch]

In order for black holes to form (generally speaking) all of the energy must be expended in the collisions. Glancing blows, that allow for continued momentum of the particles, will not deliver enough energy to compress the particles into black holes. This is why they expect only a small percentage of each run to form black holes.

Problem is, at these energies, protons look more like "a bag of potatoes" than a single particle. So it is relatively hard for that ENTIRE bag to collide coherently without some schrapnels escaping. But if that's a worry, one could slightly "untune" one of the beams wrt the other (say, colliding 7.001TeV protons onto 6.999 TeV protons). Then the center of mass of the collision has enough (1 GeV !) kinetic energy left not to be captured by the Earth's gravity.

Jupiter wasn't always where it is. Besides, Jupiter's moons suffer more tidal forces than the asteroids, and yet there they are.

Damn, never thought of that ! So it MUST be a particle accelerator fired up by an ancient civilisation...
But that means that that black hole is still there ! Help !

 

[AlphaNumeric]

Sure, but the relative motion frame of the two colliding particles is not the same as the relative motion frame of the earth, in this instance.

A particle accelerator accelerates electrons and protons parallal with the Earth's surface (it's locally flat). Therefore, the resultant particles produced also move in the vague direction of parallal to the Earth's surface (sort of spread out in a cone).

The particles hitting the upper atmosphere do anything from a glancing blow, through to aiming right at the centre of the Earth. Therefore the upper atmosphere reactions cover an enormous spectrum of energies (millions of times stronger than CERN) and also aim at every direction from "parallal to the Earth's surface" through to "aim right at the core".

The atmosphere reactions are higher energy and aim all over the place. Hence the danger from them is much much higher than that of CERN, and since we're still here 4.5 billion years after the Earth formed, the chances of a black hole being formed and swallowing us up seems small.

Not true, a rotating body eaten from within would collapse both outwardly and inward. It's a function of angular momentum (like Hawking radiation).

We'd still see the black hole orbiting around by a mysterious force perturbing the asteroids.

Jupiter wasn't always where it is. Besides, Jupiter's moons suffer more tidal forces than the asteroids, and yet there they are.

No, it's been there about as long as the other planets have.

Besides, the strength of tidal forces relates to how big the object is. A tiny moon wouldn't have too much tidal forces on it, or if it formed far from Jupiter than was captured by it's gravity it might be strong enough to survive. If a proto-planet hadn't formed yet, a passing Jupiter might have been enough to shred it and make the asteroids, or shred it into smaller bodies which could survive the tidal forces, giving rise to some of Jupiter's larger moons.

But maybe you're right. Our theories of quantum mechanics and relativity are way off and Earth wasn't the first place in the solar system to develop life, a myterious planet between Mars and Jupiter once harboured life which got destroyed by an artificial black hole when they did 1TeV+ experiments.

That is much more plausable...

 

[ubavontuba]

Problem is, at these energies, protons look more like "a bag of potatoes" than a single particle. So it is relatively hard for that ENTIRE bag to collide coherently without some schrapnels escaping.

Certainly, they expect a spectacular array of parton distribution. Their plan is to collide around a billion particles per second, of which they expect/hope to see a small percentage form nano black holes. It should indeed be a spectacular particle show.

But if that's a worry, one could slightly "untune" one of the beams wrt the other (say, colliding 7.001TeV protons onto 6.999 TeV protons). Then the center of mass of the collision has enough (1 GeV !) kinetic energy left not to be captured by the Earth's gravity.

This is an excellent suggestion, but it would require the loss of some potential energy. I think it'd be a hard sell to the scientists. It'd sure make me happy if they'd modify their experiments thusly, though.

Damn, never thought of that ! So it MUST be a particle accelerator fired up by an ancient civilisation...

Just so we're clear. I did not ever speculate so wildly. All I asked is a question. Specifically: "...how do we know that the asteroid belt wasn't the result of a black hole orbiting the center of mass of a former planet?"

Aren't there rules here against this type of speculation?

But that means that that black hole is still there ! Help !

Perhaps, perhaps not. If a planet didn't collapse around a mini black hole exactly evenly, the mini black hole could easily be flung away in the ensuing melee.

 

[ubavontuba]

A particle accelerator accelerates electrons and protons parallal with the Earth's surface (it's locally flat). Therefore, the resultant particles produced also move in the vague direction of parallal to the Earth's surface (sort of spread out in a cone).

Right, but with little or no relative momentum to the Earth's center of mass.

The particles hitting the upper atmosphere do anything from a glancing blow, through to aiming right at the centre of the Earth. Therefore the upper atmosphere reactions cover an enormous spectrum of energies (millions of times stronger than CERN) and also aim at every direction from "parallal to the Earth's surface" through to "aim right at the core".

Sure, but with great relative momentum to the Earth's center of mass. They don't strike the Earth and magically lose their momentum. Remember, momentum is conserved. If they form nano black holes, they'll procede away from or through the earth... friction free.

The atmosphere reactions are higher energy and aim all over the place. Hence the danger from them is much much higher than that of CERN, and since we're still here 4.5 billion years after the Earth formed, the chances of a black hole being formed and swallowing us up seems small.

If you'd just apply basic Newtonian Mechanics to what you are writing, you'd see that regardless of the odds of one forming, the odds of one sticking around are virtually zero. Therefore, this argument is meaningless.

We'd still see the black hole orbiting around by a mysterious force perturbing the asteroids.
No, it's been there about as long as the other planets have.

Not true, the collapse of a planet around a mini black hole isn't necessarily evenly distributed. If a planet didn't collapse around a mini black hole exactly evenly, the mini black hole could easily be flung away in the ensuing melee. The black hole might have a different or eccentric orbit, or might even have achieved solar escape. It'd be so small, It could easily be virtually undectable.

Besides, the strength of tidal forces relates to how big the object is. A tiny moon wouldn't have too much tidal forces on it, or if it formed far from Jupiter than was captured by it's gravity it might be strong enough to survive. If a proto-planet hadn't formed yet, a passing Jupiter might have been enough to shred it and make the asteroids, or shred it into smaller bodies which could survive the tidal forces, giving rise to some of Jupiter's larger moons.

Aren't Jupiter's moon orbits too circular for this to be the case? Don't captured bodies tend to have eccentric orbits? Also, why do the asteroids exist in the wide array of sizes they do then? Shouldn't they be more uniform?

But maybe you're right. Our theories of quantum mechanics and relativity are way off and Earth wasn't the first place in the solar system to develop life, a myterious planet between Mars and Jupiter once harboured life which got destroyed by an artificial black hole when they did 1TeV+ experiments.

That is much more plausable...

See above response to Vanesch.

 

[franznietzsche]

Just so we're clear. I did not ever speculate so wildly. All I asked is a question. Specifically: "...how do we know that the asteroid belt wasn't the result of a black hole orbiting the center of mass of a former planet?"

How do we know it wasn't a vogon destructor fleet?

Or the Klingons?

Or supernova jet that was so narrow as to leave the rest of the solar system unharmed?

Or another Star passing through the solar system disk?

I'm not being wildly speculating, no sirree.

Aren't Jupiter's moon orbits too circular for this to be the case? Don't captured bodies tend to have eccentric orbits? Also, why do the asteroids exist in the wide array of sizes they do then? Shouldn't they be more uniform?

Why do asteroids in exist in a wide array of sizes? Are all rocks equally strong?

Further why would the size of the asteroids be dictated by tidal forces? The planet breaks up due to tidal forces along weak lines in the rock. Why would they be uniform?

Which moons of Jupiter have circular orbits? You mean ALL 63 KNOWN moons of Jupiter have nearly perfect circular orbits? Now that's amazing. 29 of those moons are less than 4 kilometers across. Aside from the Galilean moons and the Amalthea moons (which are only the first 8 and have eccentricities all on the order of 0.001), almost all have eccentricities greater than .15, most greater than .25 and a few as great as .44, one even as great as 0.60. Pluto's eccentricity is only 0.248. Highly circular orbits indeed.

 

[Rach3]

It'd be so small, It could easily be virtually undectable.

"Virtually" undectable? A borderline case? Tell me, how do you propose to detect an order-of-TeV (10^-24 kg) mass by it's graviational effects? You seem to be missing the essential point here - this is an order-of-magnitude issue. This is 40 orders-of-magnitude from being an issue. Assuming this thing will even exist (huge assumption), and that it won't instantly evaporate (another huge assumption), then we have a totally inert object which will capture particles gravitationally on an astrophysical time scale (assuming it even survives).

Regarding your last post, extremely-relativistic objects do not fall to the earth. Orbital speeds are on order of 10^4 m/s. Relativistic speeds are on order >10^8 m/s. It escapes like a knife through butter.

 

[Rach3]

Question for the experts - if the black hole is formed from a collision of hadrons, will it interact via the strong force? I can't imagine what qcd looks like in a black hole...

 

[ubavontuba]

How do we know it wasn't a vogon destructor fleet?

Or the Klingons?

Or supernova jet that was so narrow as to leave the rest of the solar system unharmed?

Or another Star passing through the solar system disk?

I'm not being wildly speculating, no sirree.

I like your enthusiasm! That's the spirit!

All I'm saying is that the CERN scientists use the evident here-ness of solar system bodies as proof for the safety of this experiment. I'm just pointing out one not-here-ness. I don't see it as being any weaker than their arguments (especially considering that they seemed to forget about the law of conservation of momentum).

Why do asteroids in exist in a wide array of sizes? Are all rocks equally strong?

Further why would the size of the asteroids be dictated by tidal forces? The planet breaks up due to tidal forces along weak lines in the rock. Why would they be uniform?

Ah, then you think it WAS a planet that broke up, versus a void orbit caused by Jupiter's gravity? Sorry, I don't see Jupiter as being capable of actually breaking a planet at that distance. Flinging it away? Maybe. But chopping it into itty bitty pieces?

Which moons of Jupiter have circular orbits? You mean ALL 63 KNOWN moons of Jupiter have nearly perfect circular orbits? Now that's amazing. 29 of those moons are less than 4 kilometers across. Aside from the Galilean moons and the Amalthea moons (which are only the first 8 and have eccentricities all on the order of 0.001), almost all have eccentricities greater than .15, most greater than .25 and a few as great as .44, one even as great as 0.60. Pluto's eccentricity is only 0.248. Highly circular orbits indeed.

Generally speaking, the non-Gallilean moons are quite small and are obviously captured asteroids, as are Mars' moons. Most have retrograde orbits. The Galilean moons orbits are only elliptical due to Laplace resonance. Where's the evidence that they are caused by Jupiter's ability to "shred it (a proposed proto-planet) into smaller bodies which could survive the tidal forces, giving rise to some of Jupiter's larger moons."

How does Io survive these amazing chopping forces of Jupiter?

 

[ubavontuba]

"Virtually" undectable? A borderline case? Tell me, how do you propose to detect an order-of-TeV (10^-24 kg) mass by it's graviational effects?

Apparently you missed the fact that we were discussing the concept of one eating a planetary core, thus embuing it with some significant mass.

You seem to be missing the essential point here - this is an order-of-magnitude issue. This is 40 orders-of-magnitude from being an issue. Assuming this thing will even exist (huge assumption), and that it won't instantly evaporate (another huge assumption), then we have a totally inert object which will capture particles gravitationally on an astrophysical time scale (assuming it even survives).

That'd be nice, but what about the planetary core's own internal pressure and it's effects?

Regarding your last post, extremely-relativistic objects do not fall to the earth.

Where did I write that?

Orbital speeds are on order of 10^4 m/s. Relativistic speeds are on order >10^8 m/s. It escapes like a knife through butter.

My point exactly. Thereby belying the CERN scientists assumption that the existence of solar objects is proof that no harm can come to us by the creation of artificial nano black holes. If they form natuarally, they don't stick around long enough to cause any harm regardless.

 

[franznietzsche]

I like your enthusiasm! That's the spirit!

All I'm saying is that the CERN scientists use the evident here-ness of solar system bodies as proof for the safety of this experiment. I'm just pointing out one not-here-ness. I don't see it as being any weaker than their arguments (especially considering that they seemed to forget about the law of conservation of momentum).


Ah, then you think it WAS a planet that broke up, versus a void orbit caused by Jupiter's gravity? Sorry, I don't see Jupiter as being capable of actually breaking a planet at that distance. Flinging it away? Maybe. But chopping it into itty bitty pieces?

Ah, then you like putting words in my mouth. You asked why, if a planet was broken by jupiter, wouldn't the asteroids be the same size. I replied to that. I was not stating that I thought a planet formed and was subsequently broken up.

Generally speaking, the non-Gallilean moons are quite small and are obviously captured asteroids, as are Mars' moons. Most have retrograde orbits. The Galilean moons orbits are only elliptical due to Laplace resonance. Where's the evidence that they are caused by Jupiter's ability to "shred it (a proposed proto-planet) into smaller bodies which could survive the tidal forces, giving rise to some of Jupiter's larger moons."

How does Io survive these amazing chopping forces of Jupiter?

Io is literally turning itself inside out because of the tidal, not chopping, forces.

I never supported the comment that captured chunks of rock gave rise to some of Jupiter's larger moons. I object to your comment that 1) Asteroids should suddenly be the same size, and 2) that jupiter's moons mostly have circular orbits.

I think this thread has been just been a progression of greater and greater crackpottery, and should simply be locked.

 

[ubavontuba]

Ah, then you like putting words in my mouth. You asked why, if a planet was broken by jupiter, wouldn't the asteroids be the same size. I replied to that. I was not stating that I thought a planet formed and was subsequently broken up.

No, I asked; "Also, why do the asteroids exist in the wide array of sizes they do then? Shouldn't they be more uniform?" in regards to an assumption that a proto-planet hadn't ever formed.

Io is literally turning itself inside out because of the tidal, not chopping, forces.

I never supported the comment that captured chunks of rock gave rise to some of Jupiter's larger moons.

Why do you think I do? That concept came from someone else (AlphaNumeric).

Aside to Alphanumeric: Why haven't the numerous smaller moons formed up into larger ones too?

I object to your comment that 1) Asteroids should suddenly be the same size, and 2) that jupiter's moons mostly have circular orbits.

Where did I write; "Asteroids should suddenly be the same size"? As for circular orbits, I was referring to the "larger" (Galilean) moons mentioned by AlphaNumeric.

I think this thread has been just been a progression of greater and greater crackpottery, and should simply be locked.

I agree. The "experts" here haven't answered any of my questions, and have resorted to crackpot rhetoric to suppress them.

 

[Rach3]

Apparently you missed the fact that we were discussing the concept of one eating a planetary core, thus embuing it with some significant mass.

Did you miss the fact, frequently repeated in this thread, that the timescale for 'eating' even a single proton is an astronomical timescale? Or the part where a 10^9 ton black hole was shown to be harmless? (It's also microscopic, if you do the math.)

That'd be nice, but what about the planetary core's own internal pressure and it's effects?

Yes, what about them? We've already mentioned that the mass density is on the order of unity that of solids at STP. I.e., insignificant.

My point exactly. Thereby belying the CERN scientists assumption that the existence of solar objects is proof that no harm can come to us by the creation of artificial nano black holes. If they form natuarally, they don't stick around long enough to cause any harm regardless.

The same argument applies equally well to accelerator-produced black holes. Their mass is SMALL compared to the energies involved, so they must invariably be highly relativistic. Not that it would make any difference.

 

[Orion1]

Classical GR cross section...


Classical GR Planck Singularity cross-section

$$m_{Fe} = 9.274 \cdot 10^{-26} \; \text{kg}$$ - Iron nucleon mass (35.1% Terra composition)

$$m_e$$ - Terra mass
$$r_e$$ - Terra radius

$$\tau \sim \frac{1}{n \sigma v}$$

$$n_e = \frac{3 m_e}{4 \pi m_{Fe} r_e^3}$$

$$\sigma_c = \frac{\pi \hbar G}{c^3}$$

$$v_e = \sqrt{\frac{2 G m_e}{r_e}}$$

$$\tau_b = \frac{1}{n_e \sigma_c v_e} = \left( \frac{4 \pi m_{Fe} r_e^3}{3 m_e} \right) \left( \frac{c^3}{\pi \hbar G} \right) \left( \sqrt{\frac{r_e}{2G m_e}} \right)$$

Combining terms:

$$\tau_b = \frac{4 c^3 m_{Fe}}{3 \hbar} \sqrt{\frac{r_e^7}{2 G^3 m_e^3}}$$

Reference:
https://www.physicsforums.com/showpost.php?p=1001445&postcount=14
https://www.physicsforums.com/showpost.php?p=1002158&postcount=28

 

[vanesch]

Question for the experts - if the black hole is formed from a collision of hadrons, will it interact via the strong force? I can't imagine what qcd looks like in a black hole...

If it is a classical black hole, it can only interact through gravity. If it is not a classical black hole, then who's going to say how it interacts...

 

[vanesch]

My point exactly. Thereby belying the CERN scientists assumption that the existence of solar objects is proof that no harm can come to us by the creation of artificial nano black holes. If they form natuarally, they don't stick around long enough to cause any harm regardless.

Yes, but you're forgetting that this is only ONE of the arguments. Let's put all the arguments in a row:

- first of all, the LHC is not built to make black holes, contrary to what one sometimes might read in speculative articles. However, because the LHC is going to explore higher (a factor 10 about) per nucleon energies, new scenarios are not excluded (one of the reasons to build the machine is to explore a new region of course).

- the energies that will occur in the LHC are much lower than the highest energies occurring naturally in cosmic rays

- in the hypothetical case that black holes might form, normally they should evaporate through Hawking radiation

- in the hypothetical^2 case that Hawking radiation doesn't happen, normally they would have some remnant momentum, by far strong enough to have them escape the Earth's gravity (just as with cosmic ray generated hypothetical black holes)

- in the hypothetical^3 case where they'd form in EXACTLY the center of gravity of the collision (highly unlikely), and Hawking radiation doesn't happen, then they'd be captured by the earth, and they'd eat a proton every year or so according to classical estimations.

People figure that we're now in lala land and that we can take that risk. Others, with safety belts on their sofas, might not agree.

 

[ubavontuba]

Did you miss the fact, frequently repeated in this thread, that the timescale for 'eating' even a single proton is an astronomical timescale? Or the part where a 10^9 ton black hole was shown to be harmless? (It's also microscopic, if you do the math.)

That's right. Perhaps you missed my first post in this thread wherein I stated we're probably safe. However, that safety is relatively reliant on our theories being correct, and no one really knows that our theories hold true beyond the event horizon. I'm not saying the experiments are inherently dangerous and I'm not saying the experiments shouldn't be conducted. I'd just like the experiments to be performed in a "can't miss" secure way.

Yes, what about them (planetary core's own internal pressure and it's effects)? We've already mentioned that the mass density is on the order of unity that of solids at STP. I.e., insignificant.

Perhaps it is insignificant, perhaps not. Should the nano black hole have the ability to absorb whole particles (not known that they wouldn't), then they'd essentially become a drain in which the internal pressures can fllow into, right?

The same argument applies equally well to accelerator-produced black holes. Their mass is SMALL compared to the energies involved, so they must invariably be highly relativistic. Not that it would make any difference.

Highly relativistic in quantum scales? Don't these two theories come to odds here?

 

[ubavontuba]

Yes, but you're forgetting that this is only ONE of the arguments. Let's put all the arguments in a row:

- first of all, the LHC is not built to make black holes, contrary to what one sometimes might read in speculative articles. However, because the LHC is going to explore higher (a factor 10 about) per nucleon energies, new scenarios are not excluded (one of the reasons to build the machine is to explore a new region of course).

Really? That's not what the http://www.cerncourier.com/main/article/44/9/22" says. Are they lying then?

- the energies that will occur in the LHC are much lower than the highest energies occurring naturally in cosmic rays

Sure, but why does that matter? According to CERN it doesn't matter because:

It should be stated, in conclusion, that these black holes are not dangerous and do not threaten to swallow up our already much-abused planet. The theoretical arguments and the obvious harmlessness of any black holes that, according to these models, would have to be formed from the interaction of cosmic rays with celestial bodies, mean that we can regard them with perfect equanimity.

Don't you think if conservation of momentum is considered, this argument is generally baseless?

- in the hypothetical case that black holes might form, normally they should evaporate through Hawking radiation

"Should" is not the same as "will".

- in the hypothetical^2 case that Hawking radiation doesn't happen, normally they would have some remnant momentum, by far strong enough to have them escape the Earth's gravity (just as with cosmic ray generated hypothetical black holes)

Maybe, maybe not. Remember they're intent is to make thousands at a time. Can you guarantee that none will not have escape velocity? You, yourself suggested they weaken one beam for an added measure of safety. I concurred.

- in the hypothetical^3 case where they'd form in EXACTLY the center of gravity of the collision (highly unlikely), and Hawking radiation doesn't happen, then they'd be captured by the earth, and they'd eat a proton every year or so according to classical estimations.

How can you so easily trust "classical calculations" with something that's so poorly understood?

People figure that we're now in lala land and that we can take that risk. Others, with safety belts on their sofas, might not agree.

Since the world is shared by all, shouldn't everyone's opinion count?

 

[vanesch]

Really? That's not what the http://www.cerncourier.com/main/article/44/9/22" says. Are they lying then?

It's a *hypothetical* article.

Don't you think if conservation of momentum is considered, this argument is generally baseless?

Yes, but the argument ALSO goes for production in an accelerator, because normally, there's no reason why the momentum should come out 0, as there will always be remnants.

Maybe, maybe not. Remember they're intent is to make thousands at a time. Can you guarantee that none will have not have escape velocity? You, yourself suggested they weaken one beam for an added measure of safety. I concurred.

Yes, but it is a silly argument, because the probability of having one with 0 momentum coming out with "untuned" beams is the same as for tuned beams, because no such collision will not have any remnants. So one needs the remnants to perfectly balance in order for the hole to be "at rest" in the lab frame.

How can you so easily trust "classical calculations" with something that's so poorly understood?

Well, if there are scientific arguments AT ALL to say that black holes are to be produced, and if you are using scientific arguments to say that they will eat the earth, then one is allowed to use the same kind of argument to refute it, no ?
If one can use hypothetical arguments (as of now, they ARE hypothetical) to say that black holes are going to be produced in the first place, then why can one NOT use LESS hypothetical arguments to show that they will not cause any harm ? The classical theory of black holes (on which you base yourself to even call them black holes and to even think it might eat the earth) is much more solid than the HYPOTHETICAL arguments that they might be produced (namely the necessity of the universe to be at least 10-dimensional). Hawking radiation, although hypothetical, is nevertheless based upon thermodynamics mixed with some quantum ideas and classical GR, and is as such LESS hypothetical than the theory that says that BH will form in the first place.

Since the world is shared by all, shouldn't everyone's opinion count?

No, only the opinion of people knowing what they talk about should count. Know what ? Two days ago, next to where I'm working, they opened a new research center on nanotechnology, Minatec:
http://www.minatec.com/minatec_uk/index.htm

Well, at the day of its official opening, there have been demonstations by people opposed to it for various hilarious reasons...

http://biotech.indymedia.org/or/2006/05/5127.shtml

I agree that scientists shouldn't be reckless, but one shouldn't be demonstrating against one's own ignorance either, and disrupt the work of people knowing what they are doing.

 

[ubavontuba]

It's a *hypothetical* article.

Sure, but obviously considered seriously.

Yes, but the argument ALSO goes for production in an accelerator, because normally, there's no reason why the momentum should come out 0, as there will always be remnants

.

Well, according to my research, the impacts have to be nearly perfect for them to obtain the hypothetical nano black hole. If they're perfect and the beams are equal, there really will be no relative momentum to the earth.

Yes, but it is a silly argument, because the probability of having one with 0 momentum coming out with "untuned" beams is the same as for tuned beams, because no such collision will not have any remnants. So one needs the remnants to perfectly balance in order for the hole to be "at rest" in the lab frame.

See above. Also, beam differentials can be sufficient to virtually gaurantee nano black hole escape velocity. That is, they can be tuned to an energy level that would not be sufficient to create nano black holes, if escape velocity is not met. However, this may reduce the energy too much to create them to begin with.

Well, if there are scientific arguments AT ALL to say that black holes are to be produced, and if you are using scientific arguments to say that they will eat the earth, then one is allowed to use the same kind of argument to refute it, no ?
If one can use hypothetical arguments (as of now, they ARE hypothetical) to say that black holes are going to be produced in the first place, then why can one NOT use LESS hypothetical arguments to show that they will not cause any harm ?

Because producing them or not isn't nearly so imporatnt as the consideration of safety. If a young kid is playing with a handgun and he told you he unloaded it, would you believe it to be safe? Assurances of safety aren't always sufficient. The gun may indeed be safe, but are you willing to take the risk?

The classical theory of black holes (on which you base yourself to even call them black holes and to even think it might eat the earth) is much more solid than the HYPOTHETICAL arguments that they might be produced (namely the necessity of the universe to be at least 10-dimensional). Hawking radiation, although hypothetical, is nevertheless based upon thermodynamics mixed with some quantum ideas and classical GR, and is as such LESS hypothetical than the theory that says that BH will form in the first place.

I'd agree wholeheartedly with this, save it's thought they've already done this at the RHIC.

No, only the opinion of people knowing what they talk about should count.

Well I live in a democracy, and in a democracy even the less astute have a say in their fate (as they should).

Know what ? Two days ago, next to where I'm working, they opened a new research center on nanotechnology, Minatec:
[URL]http://www.minatec.com/minatec_uk/index.htm[/url

Well, at the day of its official opening, there have been demonstations by people opposed to it for various hilarious reasons...

http://biotech.indymedia.org/or/2006/05/5127.shtml

Maybe they're hilarious, maybe not. However I feel it is the institution that is responsible for easing the minds of the protesters. Remember, people once thought it was stupid to protest for environmental protections too.

I agree that scientists shouldn't be reckless, but one shouldn't be demonstrating against one's own ignorance either, and disrupt the work of people knowing what they are doing.

But do they? Aren't scientists the first to state that they're conducting these experiments because they DON"T know what will happen?