I am currently getting my Ph.D. on a dark matter search, so I know a bit about this...
The beautiful thing about the dark matter explanation is that there isn't just one piece of evidence for it. The current model of cosmology is that the universe is made of 70% dark energy, 25% dark matter, and 5% ordinary stuff. This is admittedly a really bizarre recipe. However, we get evidence from many places - the microwave background, studies of distant supernovae, studies of the chemical composition of the universe, gravitational lensing, studies of the orbits of stars and galaxies, etc. Furthermore, particle theorists have suggested that a lot of their problems would be solved by a new particle (the lightest supersymmetric particle) with exactly the properties needed to explain dark matter. The current model, as weird as it sounds, is so amazingly elegant at explaining all of these things that it's hard to imagine overturning it.
That being said, overturning it is possible. We haven't actually found the particles that cause dark matter or dark energy - the ultimate test hasn't been passed yet. The evidence for dark energy is a good deal more circumstantial than that for dark matter - we might very well need to rethink general relativity a bit. It would be amazingly exciting for our current ideas to be proven wrong.
Today, however, most physicists and astronomers think that the model we have fits the data so perfectly that it would be very difficult to come up with a different theory that works as well. Here's hoping...
Terminal velocity is the fastest speed at which you can fall. Air resistance prevents you from going any faster under gravity alone, so the exact velocity depends on your shape and size.
Yes, you do mean escape velocity. Escape velocity is the speed necessary to completely escape Earth's gravity, NOT just to reach orbit. If you reached escape velocity, you would fly off away from the earth entirely, not end up in orbit.
As to the ladder problem, the speed you get is the speed of the ladder being whipped around the earth like a rock on a string. The higher you go, the faster the end of the ladder will whip around. If you ran the ladder all the way up to geosynchronous orbit (the height where an object orbits at the same speed as earth's rotation) you could just hop off and be in that orbit. If you got off lower or higher, you wouldn't be going at the right speed to maintain that orbit and would fall to earth or rise to a higher orbit.
Incidentally, another problem is the strength of the ladder. Each separate bit is at a separate height, so each is going too slow or too fast for the orbit at that height and so wants to lead or lag behind the rest of the ladder. The stresses are too much for any ordinary material - that's why people who discuss space elevators talk about using carbon nanotube materials!
As other posters have said, the point is that we learn more about the nucleus - we find out exactly what the half-lives of these nuclei are, etc. This info could have applications to reactors, weapons, energy sources, etc. But the main point is that we know more about the universe.
And one never knows where applications will come from. Sometimes a seemingly pointless discovery has a lot of real-world consequences - superconductors, for example, have revolutionized sensor technology for medical scanners and such (though we still don't have them for power lines). Other times, the big result is the spinoffs you come up with along the way - the internet was invented as a way to coordinate particle physics experiments.
It's not really that simple. The hydrogen atom (taken as a whole) is ALWAYS a boson, there's no doubt about that - the spins add up right. What you are asking about, however, is whether you can see any interesting condensation effects because of it. That turns out to be very difficult to arrange.
You need to get a whole bunch of hydrogen atoms together in exactly the same state (no excited states, and they all must be moving with the same velocity). More importantly, quantum effects (like condensation) only become important when the (excuse the jargon) wavefunctions of the particles begin to substantially overlap. Basically, the "particles" are a little smeared out by quantum mechanics, and you only get quantum weirdness when these smears overlap. The size of the smear is inversely proportional to the mass of the object. Hydrogen atoms are 2000 times heavier than electrons, and so they have to be brought to very high densities before they can behave this way.
The upshot is that the only way we know to do this is to bring the atoms to a nearly dead stop (hence EXTREME cold) in a small region and watch the magic happen. So the atoms are always boson, but only under extreme conditions do we care.
We are, in fact, essentially certain that the BCS theory of superconductivity is correct for ordinary superconducting metals. As the previous poster pointed out, its precise predictions have been so incredibly good for the past few decades that the physics (and engineering) community are completely satisfied.
That said, there is a class of superconducting compounds (high-Tc superconductors) that we really don't understand. These compounds are generally kinds of ceramic, so they don't conduct at ALL at room temperature, but become superconducting at temperatures up to more than 100K (compared to about 4K for the standard metals).
And THAT being said, it's still true that this discovery may have nothing to do with superconductors at all.
NASA, etc. have already made use of the Lagrangian points for several other satellites and probes. Most notably, the Wilkinson Microwave Anisotropy Probe (WMAP) is currently in orbit about L2, sending back data on the cosmic microwave background, the leftover heat patterns from the Big Bang itself.
L2 is a point about 1.5 million kilometers away from the earth, essentially right "behind" the earth if you look from a vantage point near the sun. This means it's about four times farther away than the moon - much farther away from the earth than any human has ever flown. It would take an enormous amount of time and fuel (and thus money) to get anything out there, so it's something you don't do very often.
Probably. We understood light for quite a long time in terms of continuous phenomena (waves) without realizing it could better be understood in terms of particles (with wave-like behavior). Similarly, we've understood gravity in terms of continuous stuff (space-warping and gravity waves) for almost 90 years now, and are still looking for a way of understanding it in terms of particles.
When physicists speak of unifying the fundamental forces of nature, they (we) don't mean that nuclear physics is the same thing as electromagnetism, really, or that gravity waves are the same as light waves. It's more like saying that all of the fundamental forces we know of are facets of one "superforce", or that the various physical laws we've learned all make sense as consequences of a set of simpler, over-arching laws.
Physicists would say that at very high energies, the differences between the various forces melt away and the overall "superforce" behavior can be seen.
It's a little like the old story about blind men - we've spent our time understanding the seemingly unrelated behaviors of parts (trunks, tails, ears, and feet), and then begin to realize that we should really be studying the behavior of a previously unknown whole (an elephant). This doesn't mean we've explained the trunk in terms of the ears, but both as small facets of the whole.
I wouldn't really fit this into either of those categories.
Quantum mechanics deals with the weird behavior of elementary particles - the ways in which they can behave like waves, interfere, etc. This has effects on all kinds of everyday phenomena, but we still don't understand how it relates to gravity.
Newtonian mechanics includes the basic view of gravity as an instantaneous, inverse-square-law attraction between massive objects. This isn't quite that either.
The theory most relevant to the double pulsar is general relativity, Einstein's 1915 theory that views gravity as a warping of space (rather than as a simple force). Gravity waves are a consequence of this theory, and general relativity is used to model the behavior of systems like this.
In all probability, these observations have no effect on string theory. Some of the measurements serve as further confirmation for Einstein's general theory of relativity (the theory which relates gravity to the warping of space). String theory is a theory of (among other things) how gravity hooks up with the other forces in the universe at very high energies - it makes no new predictions about relatively low energy phenomena (like the pulsars), and so far essentially no precise predictions at all.
Computers don't help people learn these things. I volunteered in a high school where students didn't know how to draw or interpret a line graph, they just knew that you typed certain into the computer and it gave you a picture that satisfied the teacher, and then you could screw around behind your monitor - it was complete crap. I even know science grad students who don't really understand certain basic things about functions and calculus because they got too much help from graphing calculators and such.
Technology is a tool - you should use it to do things that you could do, but are no longer worth your time. The prerequisite for this to work is that you must first be able to do things WITHOUT machines, or you don't really understand them.
To be fair, I'm not certain which method they used in this experiment - I'd have to check the paper. But the "mass method" works for many short-lived particles because what's measured is actually a sort of a gaussian (normal curve) distribution of masses - there's an average value (the usually-quoted mass) and a spread (a wider spread means a shorter lifetime, by the uncertainty principle argument above). What they're saying is that the particle showed an unusually narrow spread (long lifetime) for a particle with that large a mass (average value).
That's the way things are done for lower-mass particles (muons, pions, etc.), but heavier ones with even shorter lifetimes still don't travel a measurable distance and have to have their lifetimes measured as in my post above.
Probably not very much, but who knows? String theory generally deals with phenomena at energy scales MUCH higher than these accelerators are dealing with, so high in fact that it really doesn't make any useful predictions about ordinary phenomena (even particle accelerator phenomena!) It's sort of like trying to predict the shape of a snowflake if all you've ever seen is steam. That's one of the main complaints about the theory - it may be right, it may be wrong, but it doesn't have any major prospects for predictions we could even test!
In essence, you measure particle lifetimes with a weird version of the uncertainty principle - a particle's energy (mass) multiplied by its lifetime gives (almost) a constant. So a particle like the proton (long-lived, perhaps immortal) has an extremely well-defined mass, while a more ephemeral particle has a broader distribution of masses (its mass isn't precisely defined, it's slightly smeared out). By measuring the particle's mass, therefore, you can estimate its lifetime. You actually do this by looking at spectra, but this is the gist.
That's a deep question, and I guess in some sense we don't know. As with most of science, you accumulate evidence and test your theory. If the theory always gives the right answer, even when you try to prove it wrong a million different ways, then you assume you're on to something (or, at least, you start believing it will probably give you the right answer to your next question). Physicists currently believe that the Standard Model is only an approximation to something a bit deeper - the things we think of as particles might be strings, or something much weirder. But we have such detailed evidence of particle behavior to so many decimal places that we don't think we're far off.
"Another Contradiction" is much too strong a statement. The Standard Model has two problems (1) it doesn't play well with gravity, so it can't be the "final answer", and (2) it is so ridiculously successful that no one knows quite where to go next in theoretical particle physics. The SM is more or less able to give the right answer to any question we're able to ask it, right up to the edges of black holes or the first tiny fraction of a second after the birth of the universe. There are some problems too complex for our calculational techniques and approximations (i.e. we can't calculate the physics of many bound states precisely or derive human behavior), but there aren't really any contradictions. The recently reported new particle is more likely to lead us to tell us our calculational approximations aren't very good, rather than that something fundamentally new (though one can always hope!) Particle physicists are always hoping to find something fundamentally wrong with the standard model - it's just an extremely good approximation to the right answer, and until the approximation breaks down you don't know how to improve it.
It's worth noting that this is far from the only such experiment searching for WIMP dark matter on earth. The Cryogenic Dark Matter Search (which I work on), for example, is in the process of an analogous experiment with silicon detectors in Minnesota's Soudan mine. Other such experiments were listed in a Scientific American article in March.
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I am currently getting my Ph.D. on a dark matter search, so I know a bit about this... The beautiful thing about the dark matter explanation is that there isn't just one piece of evidence for it. The current model of cosmology is that the universe is made of 70% dark energy, 25% dark matter, and 5% ordinary stuff. This is admittedly a really bizarre recipe. However, we get evidence from many places - the microwave background, studies of distant supernovae, studies of the chemical composition of the universe, gravitational lensing, studies of the orbits of stars and galaxies, etc. Furthermore, particle theorists have suggested that a lot of their problems would be solved by a new particle (the lightest supersymmetric particle) with exactly the properties needed to explain dark matter. The current model, as weird as it sounds, is so amazingly elegant at explaining all of these things that it's hard to imagine overturning it. That being said, overturning it is possible. We haven't actually found the particles that cause dark matter or dark energy - the ultimate test hasn't been passed yet. The evidence for dark energy is a good deal more circumstantial than that for dark matter - we might very well need to rethink general relativity a bit. It would be amazingly exciting for our current ideas to be proven wrong. Today, however, most physicists and astronomers think that the model we have fits the data so perfectly that it would be very difficult to come up with a different theory that works as well. Here's hoping...
Terminal velocity is the fastest speed at which you can fall. Air resistance prevents you from going any faster under gravity alone, so the exact velocity depends on your shape and size. Yes, you do mean escape velocity. Escape velocity is the speed necessary to completely escape Earth's gravity, NOT just to reach orbit. If you reached escape velocity, you would fly off away from the earth entirely, not end up in orbit. As to the ladder problem, the speed you get is the speed of the ladder being whipped around the earth like a rock on a string. The higher you go, the faster the end of the ladder will whip around. If you ran the ladder all the way up to geosynchronous orbit (the height where an object orbits at the same speed as earth's rotation) you could just hop off and be in that orbit. If you got off lower or higher, you wouldn't be going at the right speed to maintain that orbit and would fall to earth or rise to a higher orbit. Incidentally, another problem is the strength of the ladder. Each separate bit is at a separate height, so each is going too slow or too fast for the orbit at that height and so wants to lead or lag behind the rest of the ladder. The stresses are too much for any ordinary material - that's why people who discuss space elevators talk about using carbon nanotube materials!
As other posters have said, the point is that we learn more about the nucleus - we find out exactly what the half-lives of these nuclei are, etc. This info could have applications to reactors, weapons, energy sources, etc. But the main point is that we know more about the universe. And one never knows where applications will come from. Sometimes a seemingly pointless discovery has a lot of real-world consequences - superconductors, for example, have revolutionized sensor technology for medical scanners and such (though we still don't have them for power lines). Other times, the big result is the spinoffs you come up with along the way - the internet was invented as a way to coordinate particle physics experiments.
It's not really that simple. The hydrogen atom (taken as a whole) is ALWAYS a boson, there's no doubt about that - the spins add up right. What you are asking about, however, is whether you can see any interesting condensation effects because of it. That turns out to be very difficult to arrange. You need to get a whole bunch of hydrogen atoms together in exactly the same state (no excited states, and they all must be moving with the same velocity). More importantly, quantum effects (like condensation) only become important when the (excuse the jargon) wavefunctions of the particles begin to substantially overlap. Basically, the "particles" are a little smeared out by quantum mechanics, and you only get quantum weirdness when these smears overlap. The size of the smear is inversely proportional to the mass of the object. Hydrogen atoms are 2000 times heavier than electrons, and so they have to be brought to very high densities before they can behave this way. The upshot is that the only way we know to do this is to bring the atoms to a nearly dead stop (hence EXTREME cold) in a small region and watch the magic happen. So the atoms are always boson, but only under extreme conditions do we care.
We are, in fact, essentially certain that the BCS theory of superconductivity is correct for ordinary superconducting metals. As the previous poster pointed out, its precise predictions have been so incredibly good for the past few decades that the physics (and engineering) community are completely satisfied. That said, there is a class of superconducting compounds (high-Tc superconductors) that we really don't understand. These compounds are generally kinds of ceramic, so they don't conduct at ALL at room temperature, but become superconducting at temperatures up to more than 100K (compared to about 4K for the standard metals). And THAT being said, it's still true that this discovery may have nothing to do with superconductors at all.
NASA, etc. have already made use of the Lagrangian points for several other satellites and probes. Most notably, the Wilkinson Microwave Anisotropy Probe (WMAP) is currently in orbit about L2, sending back data on the cosmic microwave background, the leftover heat patterns from the Big Bang itself.
L2 is a point about 1.5 million kilometers away from the earth, essentially right "behind" the earth if you look from a vantage point near the sun. This means it's about four times farther away than the moon - much farther away from the earth than any human has ever flown. It would take an enormous amount of time and fuel (and thus money) to get anything out there, so it's something you don't do very often.
Probably. We understood light for quite a long time in terms of continuous phenomena (waves) without realizing it could better be understood in terms of particles (with wave-like behavior). Similarly, we've understood gravity in terms of continuous stuff (space-warping and gravity waves) for almost 90 years now, and are still looking for a way of understanding it in terms of particles.
When physicists speak of unifying the fundamental forces of nature, they (we) don't mean that nuclear physics is the same thing as electromagnetism, really, or that gravity waves are the same as light waves. It's more like saying that all of the fundamental forces we know of are facets of one "superforce", or that the various physical laws we've learned all make sense as consequences of a set of simpler, over-arching laws. Physicists would say that at very high energies, the differences between the various forces melt away and the overall "superforce" behavior can be seen. It's a little like the old story about blind men - we've spent our time understanding the seemingly unrelated behaviors of parts (trunks, tails, ears, and feet), and then begin to realize that we should really be studying the behavior of a previously unknown whole (an elephant). This doesn't mean we've explained the trunk in terms of the ears, but both as small facets of the whole.
I wouldn't really fit this into either of those categories. Quantum mechanics deals with the weird behavior of elementary particles - the ways in which they can behave like waves, interfere, etc. This has effects on all kinds of everyday phenomena, but we still don't understand how it relates to gravity. Newtonian mechanics includes the basic view of gravity as an instantaneous, inverse-square-law attraction between massive objects. This isn't quite that either. The theory most relevant to the double pulsar is general relativity, Einstein's 1915 theory that views gravity as a warping of space (rather than as a simple force). Gravity waves are a consequence of this theory, and general relativity is used to model the behavior of systems like this.
In all probability, these observations have no effect on string theory. Some of the measurements serve as further confirmation for Einstein's general theory of relativity (the theory which relates gravity to the warping of space). String theory is a theory of (among other things) how gravity hooks up with the other forces in the universe at very high energies - it makes no new predictions about relatively low energy phenomena (like the pulsars), and so far essentially no precise predictions at all.
Computers don't help people learn these things. I volunteered in a high school where students didn't know how to draw or interpret a line graph, they just knew that you typed certain into the computer and it gave you a picture that satisfied the teacher, and then you could screw around behind your monitor - it was complete crap. I even know science grad students who don't really understand certain basic things about functions and calculus because they got too much help from graphing calculators and such. Technology is a tool - you should use it to do things that you could do, but are no longer worth your time. The prerequisite for this to work is that you must first be able to do things WITHOUT machines, or you don't really understand them.
To be fair, I'm not certain which method they used in this experiment - I'd have to check the paper. But the "mass method" works for many short-lived particles because what's measured is actually a sort of a gaussian (normal curve) distribution of masses - there's an average value (the usually-quoted mass) and a spread (a wider spread means a shorter lifetime, by the uncertainty principle argument above). What they're saying is that the particle showed an unusually narrow spread (long lifetime) for a particle with that large a mass (average value).
That's the way things are done for lower-mass particles (muons, pions, etc.), but heavier ones with even shorter lifetimes still don't travel a measurable distance and have to have their lifetimes measured as in my post above.
Probably not very much, but who knows? String theory generally deals with phenomena at energy scales MUCH higher than these accelerators are dealing with, so high in fact that it really doesn't make any useful predictions about ordinary phenomena (even particle accelerator phenomena!) It's sort of like trying to predict the shape of a snowflake if all you've ever seen is steam. That's one of the main complaints about the theory - it may be right, it may be wrong, but it doesn't have any major prospects for predictions we could even test!
In essence, you measure particle lifetimes with a weird version of the uncertainty principle - a particle's energy (mass) multiplied by its lifetime gives (almost) a constant. So a particle like the proton (long-lived, perhaps immortal) has an extremely well-defined mass, while a more ephemeral particle has a broader distribution of masses (its mass isn't precisely defined, it's slightly smeared out). By measuring the particle's mass, therefore, you can estimate its lifetime. You actually do this by looking at spectra, but this is the gist.
That's a deep question, and I guess in some sense we don't know. As with most of science, you accumulate evidence and test your theory. If the theory always gives the right answer, even when you try to prove it wrong a million different ways, then you assume you're on to something (or, at least, you start believing it will probably give you the right answer to your next question). Physicists currently believe that the Standard Model is only an approximation to something a bit deeper - the things we think of as particles might be strings, or something much weirder. But we have such detailed evidence of particle behavior to so many decimal places that we don't think we're far off.
"Another Contradiction" is much too strong a statement. The Standard Model has two problems (1) it doesn't play well with gravity, so it can't be the "final answer", and (2) it is so ridiculously successful that no one knows quite where to go next in theoretical particle physics. The SM is more or less able to give the right answer to any question we're able to ask it, right up to the edges of black holes or the first tiny fraction of a second after the birth of the universe. There are some problems too complex for our calculational techniques and approximations (i.e. we can't calculate the physics of many bound states precisely or derive human behavior), but there aren't really any contradictions. The recently reported new particle is more likely to lead us to tell us our calculational approximations aren't very good, rather than that something fundamentally new (though one can always hope!) Particle physicists are always hoping to find something fundamentally wrong with the standard model - it's just an extremely good approximation to the right answer, and until the approximation breaks down you don't know how to improve it.
It's worth noting that this is far from the only such experiment searching for WIMP dark matter on earth. The Cryogenic Dark Matter Search (which I work on), for example, is in the process of an analogous experiment with silicon detectors in Minnesota's Soudan mine. Other such experiments were listed in a Scientific American article in March.