High energy physics is one of the leading fields that drives scientific progress forward. Studying antimatter is particularly cool, because at the face value it is one of the most efficient ways to store energy (Basically 100% of matter gets converted to energy). Now if only we could figure out a way to cheaply produce it without relying on fossil fuels.
> Studying antimatter is particularly cool, because at the face value it is one of the most efficient ways to store energy (Basically 100% of matter gets converted to energy).
In theory, a black hole is also a 100%-efficient converter of matter into energy, via the Hawking radiation. A microscopic BH might radiate very large amounts of Hawking radiation. The bonus is that, unlike antimatter, you can make (or at least fatten up) a BH directly from ordinary matter, without spending energy as a prior step (anti-matter is energy storage, a black hole is an energy source - if you're willing to spend some dirt as "fuel").
Of course, the problem of storage is just as bad, if not worse.
I remember reading about this on io9 quoting Louis Crane and Shawn Westmoreland of Kansas State University. (2009)
>A black hole that would survive the entire trip would have a radius of 0.9 attometers, would have a mass of 606,000 tonnes, and a power output of 160 petawatts. The lifespan of the black hole could be extended by feeding it mass, too.
I hadn't thought about black holes as an energy source. Cool idea. But where does the energy actually "come from"? With M/AM interactions, the M/AM is annihilated, which creates harvestable photons. Does the energy given off by a black hole come from the change in entropy from structured matter to unstructured Hawking radiation or something? It seems almost too easy if we can just feed any old matter into a black hole and get energy out...
The energy comes from the mass energy equivalence E=mc^2. The idea is to use a black hole as an engine for converting mass into (other kinds of) energy.
The energy comes from virtual particles. You should think of it this way : anything has a certain chance of happening, but must follow conservation laws. Conservation of energy, conservation of mass, conservation of ... (the "real" conservation laws are more complex, but ... E.g. only mass+energy+entropy is constant, not mass, nor energy, nor entropy). But small, "short term" violations are possible.
Now imagine there are particle pairs that, when added together have zero mass, zero energy, zero ... These would pop into existence in pairs everywhere and be anihilated soon after. Same is true for triples, quadruplets, ... with different probabilities. Surprise : these particles "exist" (normally for very short times).
So particle a and particle b come into existence, both particles on a path that separates them from eachother. However, because opposite charges attract (and other effects related to other forces) they will fall back into eachother after a while, anihilating eachother and leaving nothing. These are generally referred to as "virtual" particles.
Except of course if something comes between them while flying on their path. This results in multiple effects, like the Casimir pressure, and hawking radiation.
The Casimir pressure is simpler. Suppose you have 2 straight plates, and you bring them close together. So close that these virtual particles have a good chance of impacting one but not the other. If the plates are metal, the particles will generally "merge" with it (like electrons). So a tiny percentage of the virtual particles between the plates become real.
This does not affect virtual particles that are not between the plates. So there is a clear differential between vacuum interactions outside of the plates and inside. This results in a massive pressure pushing the plates together, like removing gas particles in a container results in a pressure on the outside of the container (and, in an athmosphere of large molecules, if you move plates closer together than the size of the gas molecules, there will be a pressure that pushes the plates completely together).
Likewise, in black holes what comes between the particles is an event horizon. Event horizons "erase" quantum information, only the black hole as a whole has quantum information (the reason for is that black holes are physical, localized, manifestations of the end of time : they don't have an inside as far as anything outside the black hole can detect), no individual parts of a black hole have quantum state. So if an electron crosses the event horizon the charge of the entire black hole changes instantaneously, and the point charge of the electron disappears. That means the charge pulling the particles back together (assuming an e+ and e- virtual particle pair) becomes much more distant to the particle, and if it has enough speed and a convenient direction it will fly away from the black hole. Due to conservation laws the net result is that the black hole has eaten a somehow negative-mass charged particle, and the mass has decreased. A particle has been created outside of the black hole and is flying away to infinity.
The vast majority of these particles are photons of a specific frequency, and, surprisingly, the smaller the black hole, the larger the effect (and the higher the frequencies). So spaceships would have to carry "heavy" black holes to get a decent output and would have to "feed" the black holes to avoid exploding (millions of tonnes as least, and you have to shovel in matter at a rate of 10+ kg per second to keep it stable. Or you could reflect hawking radiation back in). And of course, large black holes have large inertia (plus : how do you hold on to one ? Electrical fields can do it, but it would have to be a field so huge it baffles the imagination ...).
A 1kg black hole would be converted into energy in less than a planck second by this effect and there is nothing, even theoretically, that can hold back that energy. Such an explosion might even do what people were "afraid" would happen with CERN's Higgs experiments and disrupt the Higgs field, causing a cascading conversion of the energy "powering" inertia into photons (the higgs field is something like a magnetic field that opposes all velocity changes in mass). If this were to happen, it would look one hell of a lot like a big bang.
>So a tiny percentage of the virtual particles between the plates become real.
Let's say you get a positron/electron emission, and happen to capture the electron. Won't that free positron eventually annihilate a "real" electron, resulting in the same net effect? You still aren't creating anything long-term.
>Event horizons "erase" quantum information
I was under the impression that this was theorized to not really be the case. See http://en.wikipedia.org/wiki/Black_hole_information_paradox . There are a number of proposed solution that involve the black hole not destroying quantum information.
>the reason for is that black holes are physical, localized, manifestations of the end of time
What does this statement mean?
>So spaceships would have to carry "heavy" black holes to get a decent output and would have to "feed" the black holes to avoid exploding
What causes the black holes to explode? By "explode", do you mean they emit hawking radiation so fast that they decay quickly? If not, why are large black holes stable?
>So spaceships would have to carry "heavy" black holes to get a decent output
Didn't you say the effect was more significant with small ones?
Thanks for the explanation. Hopefully you wouldn't mind helping me clear up my confusion.
Thanks a ton for explaining like that. I love people who can take super complex concepts and break them into bite size concepts. But do explain this (simply, if possible), do black holes only eat things INSIDE their event horizon? i thought they pulled everything towards them (like shown on tv) due to their immense gravity. But from your explanation it seemed as if one of the particles accidentally wandered into the black hole and got consumed. Also, if gravity is what causes black holes to pull, wouldn't that mean it pulls +ve mass particles and push -ve mass particles?
PS: Sorry if some of my questions are super dumb. Advanced Phy really is NOT my field
Well it's a matter of perspective. It is not possible to transmit information across an event horizon. So the position of the particle that has crossed the event horizon cannot be transmitted at all, so it has no position in space different from the black hole's own position. That's the quantummechanical view, very mathematical. It can only be expressed as X, so it must be X.
In relativity theory it is actually more complex than that. Think about what an outsider (like the particle that's about to become hawking radiation) sees when you fall into a black hole. Because space itself is falling into the black hole, it takes ever longer for light to cross the distance between you and the observer. So as you approach the event horizon, first, you appear to slow down. Now this slowdown will also produce a fading effect, and a redshift. The fading effect is what's important. Whatever process produces the light travelling from you to the observer will itself slow down, so the number of photons transmitted will decrease as you approach the event horizon. Then, at the crossing point, the time for any photon to reach the observer becomes infinite, which means the photon will never be received by the observer. So what happens to an electron is the same. As it approaches the event horizon, the magnetic field of the particle fades, and the field of the black hole itself strengthens at the same time. When the particle hits the event horizon, it's field is gone.
This is why one might refer to a black hole as a location where time ends.
You should not think of matter falling into a black hole as getting consumed. There is a difference of perspectives here. What's described above this line is what one sees if observing from a comfortable distance away from the black hole. For the person falling inside of the black hole, assuming the black hole is sufficiently large, nothing extraordinary would happen. The only real phenomenon you'd see is that the distance between you and any object (not just the ones outside of the black hole) would get larger by itself. Including the distance between you and the black hole itself.
An intriguing observation you can make is that if you look at galaxies' movements from earth, what do you see ? Well, the distances between all of them are getting bigger in all directions. Suppose you place dots on a balloon, then inflate it, the distance between all the dots increases. The same is happening in 3 dimensions to galaxies. And, guess what, the edge of the universe (as measured as being "just behind" the farthest object we can see, or alternatively where the redshift would turn infinite) is exactly where you'd expect to find an event horizon (we only have accuracy for that of half a billion light years, but still, pretty big coincidence). Do we exist inside a black hole ?
Since we have never seen negative mass particles, we don't actually know whether they exist or whether gravity attracts or repulses them. While it is true that electromagnetism can both attract and repulse, that is not a given for fundamental forces. The strong force only attracts, no matter the charges or any other property of the particles involved. Since we don't have a theory that has both gravity and the other forces we can't calculate this. Since we don't have any test material we can't simply test it out. Einstein's theories claim that gravity always attracts, even particles with negative masses. Now this theory doesn't have a good basis for that claim as it doesn't have negative mass particles, but historically it has been a mistake to bet against it.
We also don't know why there is an imbalance of "negative" mass virtual particles into the black hole. The reason black holes lose mass in this process is simply because of conservation laws. You'd expect 50-50 chances of losing mass but that doesn't happen in practice. Why ? No idea. Some explanations include that particles inside the black hole don't have to follow conservation laws, only the black hole itself and anything outside of it. This would mean that inside the black hole another hawking radiation particle came into existence, with positive mass and everything. Since this can never affect anything outside, this does not actually violate any laws of physics. It is a bit of a moot point though, like asking what happens to a number after it's been divided by zero. There is no answer, anything can happen.
Is there a similarly simplified explanation for why the black hole tends to 'eat' the negative-mass halves of the virtual particle pairs but not the (or at least more often than the) positive-mass ones? Just going by your explanation above, it seems just as likely that the positive-mass particle would be captured by the black hole, emitting the negative mass one, but since the black hole loses mass through this radiation, that must not be the case.
There is no "positive" or "negative" mass. They are both virtual. Their sum-total energy is zero.
Virtual pairs appear and disappear all the time. They are like water boiling in a pot making foam; there are virtual "bubbles" everywhere around you. As long as they disappear back into nothingness, everything about them is virtual.
It's only that the event horizon throws a snag into the mechanism, and swallows up one of the particles, thereby preventing recombination. The only way for that to happen is that if the other particle gets promoted from virtual to real. The only way that could happen is if the black hole itself provides the required energy to make that particle real.
Again, the BH does not pick "positive" vs "negative" mass. It just swallows up one random member of a virtual pair. The other member, left alone, cannot recombine; it sucks up some energy from the BH's gravitational field and becomes a real particle, with positive energy and mass.
To sum it up, it's the virtual pair "foam" that slowly sucks up energy from the BH.
well by his definition they HAVE to be negative mass. Because when these particles unite, they end up having ZERO mass, energy, entropy etc. So all of their properties must be inverses of each other, including mass
Microscopic Black Holes are cooler than anti-matter if you ask me. We are only centuries of progress away from this: "Are Black Hole Starships Possible", http://arxiv.org/abs/0908.1803
My question is, how long before we can build an accelerator that deliberately aims at creating black holes, so we can understand the Quantum effects? (In space hopefully).
Interesting; though with antimatter you can control the emission by controlling M/AM recombination rate, whereas the best you could do with a BH is optimize when you feed your BH so that it's output is mostly when you need it (from what I remember the decay rate increases rapidly with decreasing size; not sure about absolute energy output though time).
What have been the useful benefits of this research?
I don't see any obvious examples--does it help things like smaller fabrication for chips?
EDIT:
Folks, I'm not being a jerk here. For example, a lot of the engineering that went into missles and the space program (integrated circuits, GPS, etc.) has application elsewhere.
Fundamental science research into materials and electromagnetics has given us wifi, radio, and television. Research into x-rays and radioactivity gave us medical x-rays and radiotagging of isotopes for understanding reactions.
High-energy physics research seems to have no immediate or even long-term application beyond satisfying "How does this stuff hold together?"--my question about chip fabrication was specifically in regards to the idea that things like advanced lithography techniques probably are advanced by this research.
The parent made this claim:
High energy physics is one of the leading fields that drives scientific progress forward.
I am simply asking this assertion to be justified and elaborated upon for those of us unfamiliar with those impacts.
Edit: Or to be more direct, and therefore less helpful, "scientific progress" is not a measure of "things that are useful to me". Scientific progress can, and historically is, made when we expand our knowledge of the world, not exclusively when we find practical applications of that knowledge.
With all respect, I got the opposite reading on this than you did. Scientific progress is just that, progress in the scientific world. That says nothing about practical applications per se, merely the increase of the worlds body of knowledge.
The question is: what WILL be the useful benefits of this research in the future. And we don't know that. That's the nature of blue sky research.
But let's look back at the 19th and 20th centuries to see what value fundamental physics research has had.
At the time research into electromagnetism was quite esoteric with little practical use. Yet, of course, it turned out to be hugely advantageous in many ways. Electric motors. Electric lighting and heating. Electric appliances in the home. Radio. RADAR. Television. Telephones. Etc. Electromagnetism defined the industrial advances of the 20th century and easily was responsible for literally quadrillions of dollars in economic value.
Later, advances in computational theory and especially quantum mechanics and condensed matter physics enabled the electronics and computational / digital communications revolutions which gave rise to the modern internet, smartphones, personal computers, and even high-efficiency/low-emission automobiles (through micro-computer based engine control). Those technologies have been responsible for easily tens of trillions of dollars of economic value (if not hundreds or more) and are utterly dependent on advancements in basic science which at the time had very little practical use. The laser, for example, was originally lampooned as a solution looking for a problem, though of course eventually it became an important component in the backbone of modern industry and commerce.
At the time absolutely none of these benefits of this research were obvious. And in many cases it took many decades up to a century or more for the benefits to be realized. But just look at the enormous RoI generated. Imagine someone in the early 20th century systematically campaigning against high-energy physics research because it had no immediate practical application. Imagine how many trillions upon trillions of modern economic activity would simply not exist today because of that short-sightedness.
I could enumerate all of the practical benefits of high-energy physics research over the last, say, 2 decades but that plays into the wrong game and misses the point. Ultimately we don't know what we are missing out on by not pursuing certain categories of knowledge. And occasionally pursuit of blue sky knowledge produces not just enormous levels of RoI but absolutely civilization defining levels of return. Thus we should pursue such research with a healthy level of investment regardless of the perceived short-term applications, because the benefits of hitting the jackpot are too great to sanely do anything else. It's possible that knowledge of the higgs-field will have no practical, economic impact on human civilizations, ever. But it's also possible that it could lead to quadrillions of dollars in economic value over the next several centuries, the only way we'll find out is if we acquire that knowledge.
The problem is that to do something useful you don’t need only energy but low entropy. The easy way to calculate it is using the Gibbs free energy http://en.wikipedia.org/wiki/Gibbs_free_energy . To produce some work and transform the radiation energy you need also a cooler heat sink to hide the entropy. The black holes are very cold, so you need something cooler. You must have a very tiny black hole with a temperature over the ambient temperature (25°C=77°F), so the heat flush from the black hole to the ambient and you can harvest a part of it as useful energy, for example with a electricity generator.
I don't think it works like that. The only known way to make antimatter is to convert energy into matter-antimatter pairs, so basically you need the same 100% of energy to produce antimatter in the first place. (In fact, I think the current physical theory prohibits any kind of matter-antimatter conversion, but I'm not a physicist so I might be wrong.)
So, if we had enough energy to make these antimatter, we could simply use the energy directly, without going through the massively inefficient step of funneling that energy into liquid helium and superconducting magnets and city-wide vacuum circles and so on.
I think OP might have been thinking of s/efficient/dense
Antimatter is certainly the densest way we know to store energy, which is great when it works. But unfortunately, it's also the densest way we know to store energy. Which is not so great when it explodes.
Technically, all forms of energy "production" we have are basically extraction from an existing store of said energy. Try reading[0], it's about the two guys who proposed a black hole powered space ship. What they suggest is extraction energy from the sun (an existing source) and making a black hole (or maybe more from the same one), and then use that to power your ship.
"With a set of four machines: black hole generator, black hole drive, power plant, and a self perpetuating black hole powered black hole generator, the potential is enormous. "
His comment is a little more meaningful and less redundant than that. For instance, I was aware of the difficulties in storing anti-matter, but it hadn't occurred to me why it would be such an efficient energy storage mechanism. Sure we can't store it well yet, but obviously that's one of the things scientists are going to be thinking about the most as they look to do more experiments with.
The lack of antimatter is an enduring mystery. And creating it is always cool. And I find it particularly fun to imagine anti-matter fusion plants producing anti-helium (more bang for your buck antimatter :-).
It thrills me that the Antiproton Decelerator is a legitimate thing that is at least as cool as it sounds. The need to slow particles down is obvious only in retrospect for me,which I'm a little ashamed to admit.
"How should we make it attractive for them [young people] to spend 5,6,7 years in our field, be satisfied, learn about excitement, but finally be qualified to find other possibilities?" -- H. Schopper
The numbers make the problem clear. In 2007, the year before CERN first powered up the LHC, the lab produced 142 master's and Ph.D. theses, according to the lab's document server. Last year it produced 327. (Fermilab chipped in 54.) That abundance seems unlikely to vanish anytime soon, as last year ATLAS had 1000 grad students and CMS had 900.
In contrast, the INSPIRE Web site, a database for particle physics, currently lists 124 postdocs worldwide in experimental high-energy physics, the sort of work LHC grads have trained for.
Let's not confuse students and fellows with missing staff. [...] Potential missing staff in some areas is a separate issue, and educational programmes are not designed to make up for it. On-the-job learning and training are not separated but dynamically linked together, benefiting to both parties. In my three years of operation, I have unfortunately witnessed cases where CERN duties and educational training became contradictory and even conflicting.
This will be difficult for LD staff to cope with. Indeed, even while giving complete satisfaction, they have no forward vision about the possibility of pursuing a career
Pensions which will be applicable to new recruits as of 1 January 2012; the Management and CERN Council adopted without any concertation and decided in June 2011 to adopt very unfavourable mesures for new recruits.
"The cost [...] has been evaluated, taking into account realistic labor prices in different countries. The total cost is X (with a western equivalent value of Y) [where Y>X]
Here's two cool thing about this experiment: Normal Hydrogen atoms do respond to magnetic field feebly. They feel repulsion while travelling in a field gradient. Anti hydrogen has same property and that's how you keep it away from normal matter.
Second, they were able to produce 25 anti-Hydrogen atoms per hour. They measured total 80 of those. A long way from anti-matter weapons :).
Even extremely strong vacuums contain large amounts of atoms, and there are the walls of the vacuum chamber, of course. When an anti-hydrogen atom collides with any normal atom an electron will annihilate with the anti-hydrogen's positron leaving behind a negatively charged anti-proton which will fairly rapidly collide with a positively charged proton in a nucleus.
Wouldn't colliding with the walls of the chamber be extremely undesirable? That seems like it would create stress/damage in the chamber, and given how sensitive and expensive ALPHA is I'd imagine that they don't want to do that, right?
It's important to keep an understanding of the scales involved here. A gram of Hydrogen contains 6e26 atoms. So a nanogram of material contains on the order of 10^17 atoms. That's ten million trillion atoms.
A "beam of antimatter" which literally annihilates the walls of the vacuum chamber it is contained within may seem dramatic but in this case we are talking about mere dozens of anti-atoms. Against walls of solid metal the damage is so minute as to be undetectable with even the finest instruments. Even if the beam were far, far stronger it would still only cause erosion at the scale of picograms per trillion anti-atoms, which isn't much concern.
We must remember we're talking about a few dozens of antiatoms here. The few gamma photons they turn into when annihilating are so utterly insignificant compared to natural background radiation it isn't even funny.
Not to "actually" here, but actually... while positron/electron annihilation results in just photons most of the time the situation with anti-proton/proton annihilation is much more complex. Initially you end up with a bunch of high energy pi-mesons (you can think about this as the quarks and anti-quarks pairing off, which isn't really correct since typically more than just 3 pi-mesons result from an annihilation, the typical number is about twice that). These then decay into showers of other particles. Photons, certainly, but also leptons/anti-leptons (muons and electrons) and neutrinos.
In terms of intensity you are absolutely correct though.
