Atom Smasher May Create "Black Saturns" 423
David Shiga writes "If we ever make black holes on Earth, they might be much stranger objects than the star-swallowing monsters known to exist in space. According to a new theory, any black hole that pops out of the Large Hadron Collider under construction in Switzerland might be surrounded by a black ring — forming a microscopic 'black Saturn'. This could happen if extra dimensions exist, as string theory suggests, and if they are large enough." An evocative excerpt from the article: "...there is an outside chance that in a few years in a tunnel near Geneva, physicists will make a black hole far smaller than a proton and circled by a squashed four-dimensional black doughnut."
Re:Now wait a minute.. (Score:5, Informative)
Physicists create string theory test
PITTSBURGH, Feb. 1 (UPI) -- Scientists have long questioned the validity of "string theory" and now U.S. physicists have created a test for the controversial "theory of everything."
[... click link to read article]
Re:Dangerous mini-black-hole (Score:5, Informative)
You're not the only one worrying, but trust me, there's no danger of this whatsoever. First of all, they will dissipate almsot instantly due to Hawking radiation. Second of all, they are so tiny that they will rarely (if ever) get close enough to swallow something else. Remember, on an atomic scale there is mostly space. And these things are not just small -they are so small its hard to fathom. They are formed by smashing together protons moving at 99.999999% the speed of light. A black hole (might) be formed, if, during the collision, the resultant density of the object is greater than the density required to form a black hole. The gravity will be no greater than the mass of the objects combining it, so you don't need to worry about it sucking things in. Let me jsut give you an example. A basketball could, theoretically, become a black hole, so long as you compressed its mass into a small enough area -but it would still have the gravitational pull of a basketball. And here, we are talking about turning protons into blackholes! In short, nothing to worry about chap!
"Thrice Upon A Time" (Score:3, Informative)
Re:Questions from the Peanut Gallery (Score:5, Informative)
All black holes emit "Hawking radiation [wikipedia.org]", which causes them to slowly lose mass. For black holes below a certain size, this evaporation due to Hawking radiation will be so fast that they won't even have a chance to grow through matter accumulation before they evaporate into nothing. I know this doesn't match up with the pop-science description of black holes--where they consume all matter around them until nothing is left--but suffice it to say that the pop-science explanation leaves out many of the important details.
So, again, the creation of micro-black-holes is nothing to worry about. Remember that although the energies in the LHC are really massive, there are other similarly high-energy natural events occuring throughout the universe, and they appear not to routinely form micro-black-holes that consume everything around them. Creating stable (i.e.: big) black holes appears to be a comparatively rare event.
Some people are not appeased by the above arguments and point out that our current theory of particle physics may be lacking in some unforseen way, and we will destroy ourselves. Then again, the only reason to think a black hole will form at all is because of the current theory of particle physics. If that theory is wrong, it's more likely that... well... no black hole will form at all. (Again, look around the universe and notice the distinct lack of universe-consuming mega-black-holes.)
Re:Alway with the bloody String Theory (Score:1, Informative)
If experimental results start supporting string theory, then it will move from the realm of 'speculative' to 'possible.' If the experimental result also supports other (higher-dimensional) theories, then we can start tuning the experiments to show which theory is correct...
But at present we don't even have concrete experimental evidence that these higher-dimensions exist, so verification of that postulate would be huge. It would make all of these alternate theories (of which string theory is one) finally falsifiable.
Re:Dangerous mini-black-hole (Score:5, Informative)
Earth-cosmic ray collisions occur at an absolutely fantastic rate, higher than the LHC would ever even dream of. The energies of cosmic rays are distributed across an extremely broad spectrum, extending both above and below LHC energies. If there is any chance of the LHC making an Earth swallowing black hole, then there is precious little chance of the earth being outside of a black hole by tomorrow morning, much less any chance of the earth having survived 4.5 billion years.
Furthermore, pretty much everything in the galaxy, and presumably in the universe, experiences a cosmic ray flux comparable to what the earth sees. If the LHC were going to make planet or star swallowing black holes, then the sky would be mostly nothing but black holes.
Re:Dangerous mini-black-hole (Score:3, Informative)
Besides, the resultant black hole would be absolutely minute - much much smaller than a proton. At that scale, even the densest of earthly materials is just so much empty space. The mean free path of any such hole would be absolutely huge, meaning that the chances of it getting close enough to even a small handful of atoms to swallow them as it passes through the planet are absolutely tiny.
Dan Simmons called this "The Big Mistake"
Dan Simmons writes science fiction. Perhaps you should try reading a little less sci-fi and a little more real science before yelling at people.
Re:Now wait a minute.. (Score:5, Informative)
There are ways to test QFT, and there are ways to test string theory. For instance: Lorentz invariance. Just because nobody reasonably suspects that Lorentz invariance will turn out to not be a real feature of our universe does not mean that it is not a testable prediction. The frameworks of both QFT and string theory include Lorentz invariance.
Furthermore, string theory is not as purely descriptive as you seem to think. It begins with some quite simple and quite basic first principles, and then attempts to derive all of physics from those. If it turns out that they can't describe all of physics from those principles, then they'll have to go back to the drawing board and look for new principles. Those principles are hypotheses. They have left the observation up to other physicists, and are using the existing theories as a description of those observations. So, they are letting observation refine their hypotheses.
If they were merely looking for a way to describe all our known data, then they would just say "Well, our theory is: The Data Is As It Is." Such a theory would be absolutely right. It would even be science. It would be pretty poor science, but it would be science nonetheless. If they are truly looking for the simplest way to make equations that work out to cover all the physics that we know, then it is absolutely science. Simplicity and good description of data are what make a scientific theory good. And yes, they are trying to describe data. If they are trying to make particular limits of their theory match up with extant theories that are known to work in those same limits, then they are trying to describe data, simply because those extant theories are only extant because they themselves describe data.
Now, I don't much care for the particular approach that string theory takes, but that in no way makes it not science.
As I said, learn a little physics before you try and comment on physics. Learn a little bit more of the details of what string theorists actually do, and also learn a little bit more of the details of how every other scientific theory in existence was formulated. Not that they were all identical to string theory at some point, but at base, they all tried to find the simplest way of making equations describe data, and sometimes those data were represented by other equations.
Re:Third of all... (Score:5, Informative)
This is not scientific thinking, and it shouldn't be granted any credence. You need to get some evidence to support your views. Your cautionary assertion is on par with the following: never write the letters "CKGJSHDFKLNJNSDFH" on a piece of paper -we don't know what would happen since it has never been done, and it might end life on earth (you can't rule it out completely). Both claims are just about equally substantiated.
Second, the only reason we have to believe in black holes is because of our scientific models, and now you are jumping up and down warning us that our models might be wrong? You would be standing on firmer philosophical ground by rejecting the notion that a black hole will be created at all (there you are just being a skeptic about theoretical entities). But your position as it stands is contradictory -you claim our models might be wrong and black holes might eat the planet, but yet you trust those theories in predicting the appearance of a black hole.
Re:Dangerous mini-black-hole (Score:5, Informative)
Cosmics have energies spread out over an absolutely huge range of energies. Their timing and location are nigh unto impossible to predict. We don't get anything like a 0 net momentum collision between a cosmic ray and an atmospheric atom. The upper atmosphere is an incredibly noisy place, primarily because of cosmics. We would have an awful hard time telling the difference between a particle that originated from a cosmic-atmosphere collision we were interested in and a stray particle that came from the hadron shower of some other cosmic-atmosphere collision.
Re:4D black donut? (Score:4, Informative)
Re:Ringed black hole (Score:5, Informative)
Suppose you had a rectangular prism-shaped room with 2 doors, exactly opposite each other on the North and South walls, respectively. Actually, better yet, suppose that the entire North wall and the entire South wall are completely taken up by their doors. Now, suppose that when you walk out the North door, you are simultaneously walking in the South door. This doesn't happen normally (obviously), but with a sufficiently weird topology of space, it could. It is certainly imaginable. The North door and the South door are actually the same place. Now, of course, you can measure this room, length height and width. You might say "but North to South it would be infinitely big!", but it isn't. Take meter sticks, and lay them end to end, starting in the middle of the room, with them oriented N-S. Eventually, because the North and South doors are the same place, you'll wrap back around, and find yourself laying the last meter stick on top of the first one. The number of sticks that you laid down is the length of the room N-S in meters.
Now imagine that your room is that trash dump in Star Wars, where the walls start closing in. Move the North wall closer and closer to the South wall, so that you can only lay down two meter sticks before they start overlapping, and then one meter stick, and then your one meter stick starts overlapping itself, so you switch to centimeter sticks. The size of your N-S dimension has decreased, say to 50 cm. The East-West and Up-Down dimensions are still plenty big, say 5 meters, and they have hard walls, ceilings, and floors, none of this wrapping around nonsense.
Now, suppose that you have a stick 25 cm long. You can orient it in whatever direction you like in this space. It has no trouble existing. Now take one of those meter sticks you had before. You can't orient it however you want, because if you try to turn it to point exactly N-S, it will run into itself. Now suppose you have a 25 cm diameter beach ball. It has no problem existing. But try to imagine a 1 meter diameter beach ball. It can't happen. No way no how. No matter how you turn the thing (unless you deflate it, of course), it will run into itself.
So, an essentially 1-d object, the meter stick, can exist in this space, but only if you turn it certain ways. It can exist even though it is larger than the smallest dimension. However, the 3-d object, the beach ball, can only exist in this space if it is smaller than the smallest dimension, otherwise it runs into itself.
This is precisely how the "black saturn" can only exist at microscopic scales. It is a 4-d object, and all our theories of extra dimensions (at least all of them that have any real following) have no more than 3 dimensions which are actually macroscopic. So if you have an object which is roughly 4-spherical, that is the same size in 4 dimensions, it can only exist if it is smaller than the 4th largest dimension (the three largest being our normal 3 space).
Another way to look at the room I described is that at scales above 50cm, it is actually a 2-d space. Only at small scales (< 50cm) is it really 3-d. Only at really really tiny scales is our space 4 (or more) dimensional (in most extra dimension theories), at any larger scales, it is 3-d. (Of course, I'm not counting time here. Only spacial dimensions.)
Re:Creating black holes is always a bad idea. (Score:5, Informative)
A larger star collapsing will form a larger black hole of the SAME mass.
A molecule collapsing to form a black hole[forced to] will form a black hole of the same mass of the molecule.
The smaller the black hole [smaller mass], the faster it will evaporate due to Hawkins Radiation.
Re:Now wait a minute.. (Score:5, Informative)
Two, as I said to another reply making this same objection, the "The Data Is As It Is" theory could be understood to implicitly say "Under exactly the same conditions as we did our experiment, you will get exactly the same results as we did", which is dead easy to falsify.
Three, a measurement which breaks lorentz invariance would destroy string theory (as well as much of the rest of the last century of physics). There is no "change the words of the proposer" here (although in general, if you change the assumptions of a theory, you pretty much have to change everything. They are assumptions because they are fundamental and necessary.). This is one regard in which string theory absolutely can be wrong, and lorentz invariance absolutely is testable and is frequently tested.
Four, QFT is just as much, if not more so, of a "calibration model". QFT can describe a huge number of conceivable universes, probably more than string theory can. For instance, string theory nails down a number of dimensions. QFT does not. It is possible for us to do measurements on the number of dimensions. They are indirect, and they have a difficult time ruling out more dimensions than we have yet measured, but they can fairly easily rule out fewer dimensions than we have yet measured. So, it is conceivable that we might do LED analyses at the LHC and find that it looks like there are at least 3,972 dimensions. QFT would have no problem with this. String theory would. Yet another way in which string theory is definitely falsifiable.
Five, even the SM, the baby of QFT and of string theory opponents, is very much a calibration model in all kinds of ways. In fact, that is one of the principal criticisms of the SM. It has far too many free parameters that can only be determined by experiment. Once a particular string model (and here I mean string model : string theory
Six, if we built a sufficiently powerful particle accelerator, we could probe down to string length scales (and no, I'm pretty sure that the string length scale is moderately fundamental, so the string theorists couldn't just say "well, ok, strings are smaller than that then."), and see whether we saw strings or point particles. QFT predicts points, string theory predicts (obviously) strings. This is a harsh test of string theory, which makes it falsifiable. The fact that today we do not have the technology to carry out such a test in no way affects the "scientificness" of string theory.
Seven, as I've said above, string theory can be wrong, and it is science. It is not science that I personally like, but it is science.
"It is not science" is the principle criticism of string theory coming from the non-physicist public. I have very rarely heard this criticism coming from physicists. Please keep in mind that pop-science-book-writing physicists are a tiny tiny minority of all physicists. Trust pop science no farther than you can throw it, as it is practically necessarily fraught with errors. If you wrote a pop-science book without errors in description, you would find that you had in fact written a science textbook, and it would not be very accessible to the pop-science reading public.
Re:Now wait a minute.. (Score:2, Informative)
Your question makes no sense because "dimensions" aren't always just abstract ideas: when we say time is the fourth "dimension" it is because of the role time plays when you consider the coordinates of objects in good old 3D reality. I.e when you give the location of an object you need to specify the x, y, z and the WHEN. The wikipedia article on special relativity is a really good primer on this, check it out. As for other "dimensions", they are indeed mathematical abstractions used in equations that involve linear algebra where vector spaces can be 5 dimensional..etc even though that has nothing to do with Physical reality. There is no "extra dimension" from what I know, just matrices and equations used to model the dimensions we know by bringing in other abstractions.
A lot of mathematics is needed to even begin looking at serious theoretical physics. Hilbert, Max Born and others are the legs that Einstein's later work stands on.