Prospects and Limits For the LHC's Capabilities To Test String Theory 148
StartsWithABang writes: The Large Hadron Collider has just been upgraded, and is now making the highest energy collisions of any human-made machine ever. But even at 13 TeV, what are the prospects for testing String Theory, considering that the string energy scale should be up at around 10^19 GeV or so? Surprisingly, there are a number of phenomenological consequences that should emerge, and looking at what we've seen so far, they may disfavor String Theory after all.
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...he was making a game reference, and what he got are unforeseen consequences. Sounds about right to me.
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nicely put.
i'm proud of yer, son,
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Maybe the GP is female and enjoys having a real cock in her pussy, instead of the spaghetti noodle hanging off your crotch.
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Those 400MHz klystrons must have some hellatious waveguides to feed!
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Because they assume everyone uses a phone with a 4 inch screen.
...and even more inaccurate than usual (Score:5, Interesting)
Similarly the use of String Theory to solve non-perturbative QCD is not some new, fundamental principle but is simply a result of applying the maths developed for String Theory to a different problem. Hence studying the quark-gluon plasma is, at best, a test of some of the maths developed for String Theory but really tells us nothing at all about the physics. For a simpler analogy if you demonstrate that calculus works this does not imply that Newton's Laws of Motion are correct even though calculus was co-invented by Newton so he could write down and apply his laws.
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Can't we muster a popular appeal against posting vapid articles from medium.com here? Please? Or at least post them with a mandatory icon warning people that this is heavy on glossy pictures and light on worthwhile information?
Who writes this stuff anyway? Clearly somebody with a strong interest in big photos of impressive looking things; whereas I suspect that most of us would be far more interested in good, solid, factual information, without illustrations, unless strictly needed. Is it 'samzenpus'? Does
Not a surprise (Score:1)
String Theory is the result of an attempt to rectify QM and Relativity using pure math. It was not born from evidence. So, evidence will; be its undoing,
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Was that semicolon an indication for putting your sunglasses on?
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More likely the semicolon was a deliberate attempt at getting attention, which would result in more responses, higher mods, and greater visiblity.
(Yes, I did that on porpose, too).
(and that)
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It was not born from evidence.
Quite the opposite, it is born from the evidence that general relativity and quantum mechanics hold quite strongly, and is an attempt to find a theory that covers both. This is a process that has been done many times in physics, finding a theory that is a superset of different ideas, giving a more concise, general explanation. Sometimes in the past it worked, sometimes it didn't, as with any proposed theory.
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Maxwell's equations. The goddam speed of light pops out of it. It pops right out of the math(s). IMO it's one of the most startling discoveries ever made and proof of the accuracy of using mathematics to model our Universe.
String Theory\0 (Score:5, Funny)
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I'm wondering why all the heavy particles that were found with the colliders, were not observed during all the nuclear tests that were done during the 30 or years or so from 1945 till 1975.
I know nothing of particle physics, but I thought it was that the particles are very short lived?
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Also, likely a nuclear explosion would have destroyed the detector used to discover the extremely short lived heavy particles.
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Re:String Theory\0 (Score:5, Funny)
they were certainly created, but they occur amongst BILLIONS of other events. Part of the magic of the LHC is to ignore all of this and focus only on the interesting EXTREMELY RARE interactions.
I wish the interactions of your fingers and the shift/caps lock keys were extremely rare.
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they were certainly created, but they occur amongst BILLIONS of other events. Part of the magic of the LHC is to ignore all of this and focus only on the interesting EXTREMELY RARE interactions.
I wish the interactions of your fingers and the shift/caps lock keys were extremely rare.
+5 funny - people say A/C posts should be ignored. The fools.
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Fission and fusion bombs produce low energy particles, compared to colliders. Less than a couple dozen million electron volts at most.
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Better instrumentation and better understanding would be my guesses.
It's awfully hard to measure things you don't know are there, don't expect to be there, and don't have things which can detect them.
I'm pretty sure Higgs was mocked for his idea of the Higgs boson. Flash forward, and our understanding is much better ...
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String theory encompasses more than just C strings; there's no null terminators on many other string types, such as cheese, for example.
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My roommate is an expert on string theory and the laws of grabbity. I really should trim her claws.
\r\0\0\0String Theory (Score:2)
One quote from the article that is nice... (Score:3, Insightful)
"The production of tiny black holes is one of the predictions. "
No concerns at all with that one.
Man I hope they know what they are doing.
Re:One quote from the article that is nice... (Score:5, Informative)
More energetic collisions happen in the upper atmosphere all the time when cosmic rays enter. If there was concern of black holes eating the earth, it would already have happened.
Here's some great camera footage at the LHC for you if you are really concerned:
http://www.cyriak.co.uk/lhc/lh... [cyriak.co.uk]
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That webcam is pretty cool, I wonder how long befo
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It's so weird how the sentence gets cut off, but there is still time to click the "Submit" button.
Time distortion!
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Perhaps he was dictating?
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There's one substantial difference though - reaction density. Creating one micro black hole or strangelet in the upper atmosphere may be a non-issue, it will evaporate long before it can absorb enough matter to stabilize. Create dozens or thousands of them within a miniscule target region and a small fraction of a second though, and you have to start worrying about how they might interact with each other.
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Assuming of course, that it behaves according to our untested theories.
a microscopic black hole won't hurt you (Score:5, Informative)
"The production of tiny black holes is one of the predictions. "
Man I hope they know what they are doing.
Microscopic black holes disappear quickly due to Hawking radiation. So if your goal is to destroy the earth, creating a microscopic black hole is not the way you want to go.
The bigger a black hole is, the more slowly it evaporates. So if you want your black hole to do any damage, it'll have to be more than a certain threshold size. Turns out that minimum-size black hole you'll need to destroy Earth is roughly the mass of Mt Everest.
If we take the density of such a black hole to be 3 * 10^18 kg/m^3, then our black hole will look like a ball with a radius of about 12 cm, i.e. it looks like a soccer ball.*
See here [qntm.org] for more details.
* no idea if my density assumption is reasonable. I'm not a physicist -- I got the number from 20 seconds of googling. The volume of your black hole may vary.
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Turns out that minimum-size black hole you'll need to destroy Earth is roughly the mass of Mt Everest.
This must be why evil mad scientists are always found underneath large volcanoes. Everything is clear to me now.
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Turns out that minimum-size black hole you'll need to destroy Earth is roughly the mass of Mt Everest.
This must be why evil mad scientists are always found underneath large volcanoes. Everything is clear to me now.
Well... that, and the unlimited geothermal power, and, of course, the availability of lava pools for unnecessarily slow dipping mechanisms!
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It's denser than that. The Schwartzschild radius of a black hole with a mass around 10^15 kg (a rough guess) is about 10^-12 meters (about a picometer). Give or take a few orders of magnitude. Wolfram Alpha [wolframalpha.com] has a convenient Schwartzschild radius calculator. The evaporation time for a black hole that big is 10^30 seconds.
The smaller a black hole is, the denser. The number you give is for a star-sized black hole. There isn't any known way to form grain-of-sand sized black holes, though they might have formed
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That's fun. A 1 meter radius blackhole would have a mass of around 673500000000000000000000000 Kg
You could put it in the back of a minivan and drive it around advanced societies, giving the less advanced places time to catch up.
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I propose we adopt "mass of Mt Everest" as a new Slashdot standard of measument - measuring mass in Libraries of Congress was always awkward.
I believe the mass of Mt Everest estimate is correct for the Earth-destroying black hole - it's the point at which matter infall at the density of the Earth's interior exceeds Hawking radiation. In a vacuum, the magic mass is about the mass of the moon - the point at which the Hawking radiation is cooler than the CMBR, and so you won't have a net loss for 10^lots year
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Found this:
http://xaonon.dyndns.org/hawki... [dyndns.org]
It says that a 3K black hole has a mass of 4x10^22 kg, a bit larger than the Everest-sized black hole.
The Everest-hole hole is extremely hot, 10^8 K, but it's still radiating so slowly that it'll take 10^21 years to evaporate, so it would be more than enough to destroy the earth.
I'm not quite sure how to solve for one that would be hot enough to suck in the earth before evaporating, but I see that a black hole that would last 1 second is a mere 70 million kilogram
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It says that a 3K black hole has a mass of 4x10^22 kg, a bit larger than the Everest-sized black hole.
The moon is just over 7x10^22 kg.
m not quite sure how to solve for one that would be hot enough to suck in the earth before evaporating
The hard part is determining the rate at which a small black hole would consume matter. Very small black holes simply don't have the cross-section to consume matter fast enough to live. The hole would have to live long enough (and still have a cross-section large enough) for the few seconds needed to fall through the ground and get deep enough to pass the water table and into denser crust. From that point it's a matter of its cross-section, speed, and the density of the r
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Are you sure? ISTM that it would initially prefer either electrons or protons, and when it had swallowed a couple of them it would repell any more. (Electrons are smaller, so it might prefer them, but they are also more uncertain as to their position, so it might prefer a proton.)
So say it swallowed an iron nucleus. This would give it a strong positive charge, so it would repell any additional nucleus. The question is could it also swallow electrons, or would they go into orbit around it?
*My* guess says
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I know the "proton-sized black hole with a positive charge" with an electron orbiting it has been studied - but I don't know what was concluded. But you won't get "orbits" out to maybe 3x the radius of a black hole, so no danger of that for the Everest hole.
The LHC uses two beams colliding from opposite directions, so the total momentum of a collision is low. If most of the energy of collision goes into making the black hole, then the mass of the black hole would be much higher than whatever collided, and
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Yes, it would be much lower. But that "much lower" would still be expected to be well above escape velocity. I mean the difference between 0.999...c (say 290,000 km/s) and 12 km/s is HUGE. (And I rounded the speed of the particle down, and escape velocity up.)
Even a 99.99% cancellation of velocities would still be well above escape velocity. It's true, though, a 99.999% cancellation would be below escape velocity. That kind of efficiency after a collision seems (to me) unlikely.
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Close but the Schwartzschild radius solution only applies to non-rotating bodies and any particle I can think of that is subject to relativistic mass increases also have spin, a closer fit would be a Kerr–Newman metric [wikipedia.org], however I'd assume that these solutions ignore external gravitational fields, which might be valid approximation over interstellar distances, it might not be valid in Earth's atmosphere for cosmic rays or inside the LHC. Perhaps a real physicist could chime in with a more learned point
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We really have no idea what kind of profound ramifications this could have for the planet and even beyond. Let's find out.
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The singularities (they are not blackholes) have a diameter smaller than the width of the nucleus of an atom. So, even if they were created, survived more than a trillionth of a second without evaporating, or any of the other improbabilities that come along with this... the statistical likelihood of them colliding with any particle at all is basically 0. If it were possible, every star in the universe would have collapsed into a black hole seconds after forming.
When they building a accelerator around the ev
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I'm seeing an awful lot of assumptions there.
1a) I don't see how limiting research to areas where we don't specifically predict potentially dangerous outcomes translates to scientific stagnation. Worst case scenario, we could do such experiments on the moon - if it turned into a black hole, supermassive stranglet, etc. only nighttime lighting (and any unfortunate species unable to adapt) would be affected on Earth, and there would no doubt be lots of useful applications for such an exotic moon. And that wo
Exotic Moon (Score:2)
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Absolutely, the technology is not there yet. But the fundamental science underlying the technology is. The two are interconnected, but NOT synonymous.
As for humanity changing - you are talking about human *technology*, I am talking about humans themselves. Two very different things. We've become far less lethally violent as population density has increased and made violence much more destabilizing, but otherwise we seem to be basically the same creatures as described in the most ancient legends.
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Oh, and as for my assumptions - yes, I could be wrong - but of all the things that might possibly emerge from new fundamental physics, it seems *extremely* unlikely that any of it would be particularly applicable to non-physics science. Well, beyond the potential fount of xeno-biological knowledge and/or interaction with alien civilizations if it led to some sort of FTL travel :-D.
Our technology is already on the cusp of allowing us to observe living organisms on the atomic level - while it's not impossibl
Which string theory? (Score:3)
Aren't there like 40 things called string theory, ranging from merely odd or unlikely all the way up to batshit crazy?
I've gotten the sense over the years there's so many things called string theory you can't coherently say what any of it is, or how you'd test it.
Hell, I'm not even convinced many physicists take it seriously. Which means for the layperson, it mostly sounds like gibberish.
It just has all the hallmarks of being so unexplainable as to be meaningless. Which I'm sure is grounded in my lack of understanding due to the fact that it's so magical as to be unexplainable.
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Which means for the layperson, it mostly sounds like gibberish.
In fairness, almost everything from high-energy physics sounds like gibberish to everyone but the people running the experiments.
Re:Which string theory? (Score:5, Interesting)
Sure, but ... if Richard Feynmann [wikipedia.org]
I'll flat out admit I can't come close to understanding the voodoo which is string theory.
But that Feynman didn't either, and I've heard more recent quotes from physicists who basically say they don't know what it is either ... I feel I'm in good company.
I accept that my tiny little money brain isn't up to the task. But I'm not the only one saying "WTF?" about string theory.
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No, I agree. If Feynmann can't follow their calculations, there's something largely amiss. Then again, that was a while ago and for all I know they might be making perfect sense now.
But I still contend that "it sounds like gibberish to laypeople" is a pretty low bar to set. It's almost impossible to describe something like QCD to non-phycisists without stopping twice a sentence - "well, not a literal color", "not 'up' like in 'gravity'", etc. - even at the high school textbook level.
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Oh, sure. There's a lot of background knowledge required to follow any of it.
But, honestly, even among people with a reasonable foundation in science ... string theory falls into two camps: a) those who make crazy strange metaphors as if they understand it, and b) those who roll their eyes at the people who use crazy strange metaphors as if they understand it.
So, I conclude that string theory causes an extreme polarization of dork-ions, a lot of hyperbole, and way too little actual understanding or predi
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But.. But... It has "theory" in the name that means that you are just not smart enough to understand and I am a super genius! If I use my patented off hand metaphor to describe it, I could get my own TV show! However, describing dork-ions seems self defeating.
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It's not that bad, you just have to read "The Jabberwocky" to them for a warm up first.
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Imagine a "theory" with a bunch of adjustments. So many adjustmentrs that no matter what happens, there is some adjustment that canm be made such that it "retroactively) predicts it. That is string theory.
The big problem with string "theory" is that it predicts everything and so, nothing.
String toolkit might be a better name. It is just that, a bag of parts and tools that might one day be used to construct a theory that predicts something in particular.
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Imagine a "theory" with a bunch of adjustments. So many adjustmentrs that no matter what happens, there is some adjustment that canm be made such that it "retroactively) predicts it. That is string theory.
The big problem with string "theory" is that it predicts everything and so, nothing.
String toolkit might be a better name. It is just that, a bag of parts and tools that might one day be used to construct a theory that predicts something in particular.
So your saying that Climatology is a sub-discipline of String Theory?
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Climatology has proven much more predictive than string theory.
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Get back with me when they make a prediction outside their error bars.
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Already happened unless you stretch the error bars because it's inconvenient to your political convictions.
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Actually, quantum mechanics made a few actual predictions that proved to be dead on.
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Calculus was never claimed to be anything else.
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True, but it seems string theory attracts more woo and people trying to claim it predicts something.
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Feynman died in the mid 80s. We've had a good couple of "revolutions" in string theory since. Not that his comments aren't to be taken seriously, but the "string theory" he talked about then is not the "string theory" we talk about now. We now effectively have four or five "string theories" each of which are related to the others via "dualities" (ultimately, ways of transforming aspects of one theory to find exactly aspects of another), and are also related via a duality to supergravity. This both suggests
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"It might still be true" also leads to discoveries. If you have reason to believe a theory is correct, anomalies are a way to explore previously unexplained cases. To give an example, Newtonian gravitation predicted Kepler's laws and some variations from them, but not the exact orbit of Saturn. It turned out that the anomalies could be explained by a planet further out, and one was indeed found. It also had problems with the orbit of Mercury, but that turned out to be a relativistic effect, a case wher
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There may be 40 things called string theory, but they all boil down to a few things:
- point particles are actually vibrating strings
- there are extra spatial dimensions
- there isn't much in terms of specific testable predictions made by string theory
The LHC tests may show things that hint at extra dimensions (of small but testable size, not planck length). This in and of itself wouldn't prove any of the individual string theories. But showing nothing that could indicate super symme
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Unfortunately 'silly string' theory has taken over entire physics departments (such as at Princeton) and wasted a huge amount of mind share. Cold fusion is mote in comparison.
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See also Peter Woit's book "not even wrong" and his blog here. http://www.math.columbia.edu/~... [columbia.edu]
My question is: What observation from the LHC would disprove string theory? If ST is compatible with every possible experimental outcome, it predicts nothing.
Much more than 40! (Score:2)
Aren't there like 40 things called string theory, ranging from merely odd or unlikely all the way up to batshit crazy?
Much more than 40!
For every string theorist, there are two string theories (something to do with pair production....).
You can't falsify string theory (Score:1)
The problem is, that there are 10^520 [wikipedia.org] possible variations of string theory models that can represent our universe, and if we fail to find any of the results 'predicted' by string theory, then string theorists can just re-arrange the variables in their models, and pick from one of the other 10^520 variations - and can shift the goalposts like this pretty much forever, unless we have the gigantic breakthrough in string theory research, that we've been waiting for 30 years already, with no end/hope in sight...
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or just go with what Feynman said, it's experimentally unverifiable and thus nonsense and a waste of time
Checklist (Score:1)
Pop-sci - check
medium.com - check
Ethan - check
Every single fucking day - check
Slashdot shillsquad is good to go
they may disfavor String Theory after all (Score:1)
After all?
TeV, GeV (Score:5, Insightful)
But even at 13 TeV, what are the prospects for testing String Theory, considering that the string energy scale should be up at around 10^19 GeV or so?
Why the switch to GeV? Stick with a prefix and call it 10^16 TeV.
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I'll second that! I was thinking the same thing; why is GeV somehow bigger that TeV, or is it a typo, or something else? I'm going to read about this on wikipedia. I can usually catch a gist or two from there.
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My calculator tells me that 10^16 = 10 XOR 16 = 26. :)
Only 13 TeV to go!
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Wait, is that metric TeV, or English Customary TeV?
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One GeV is the approximate (order-of-magnitude) scale of QCD quark confinement. Thus it is the scale measure that particle physicists usually think in terms of. I imagine that people who study atomic-scale interactions think in terms of Angstroms for the same reason. In fact it is pretty common to use a set of units in which c = hbar = 1 so that energy, momentum, and mass can be conveniently measured in terms of GeV, GeV/c, and GeV/c^2. If you like to do that sort of thing.
Cue Prof. Frink (Score:1)
"You can tell everyone that you were here when the human race learned...
that this collider isn't powerful enough to tell us anything new.
(Paraphrasing from memory - that ep was on last night.)
Watch Leonard Susskind in action (Score:2)
If you'd like to actually know something about string theory, I suggest watching some of Leonard Susskind's lectures:
https://www.youtube.com/watch?... [youtube.com]
You will then be in the position of being able to intelligently criticize the theory, instead of quoting other people's jibes.
Susskind is not interested in bullshitting anyone, by the way... quoting from memory: "This is why a lot of us found string theory to be so promising. And it keeps promising and promising."
String theory more like string queery (Score:1)
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Dude If that thing spawns an "Earth eating black hole" living next door to it would be like about Mars. What everybody forgets is a blackhole has conservation of mass, charge and angular momentum, so a blackhole whizzing around the LHC ring would act pretty much like every other thingy whizzing around with the same mass, charge and angular momentum. Even if the blackhole escaped the ring, it would only be a blackhole as long as it's energy was high enough to maintain it's event horizon; that energy is depen