It's absolutely non-trivial to do, but well within current capabilities. Just to blow your mind a bit, LISA must be sensitive to changes in arm length on the order of picometers... when the spacecraft are so far apart that round trip time for the light is 33 seconds! The only really tricky part in all of it is eliminating systematic errors from interactions with the LISA test masses and the spacecraft, but there has already been some testing done on test mass/spacecraft interaction, and they show the noise floor is low enough for good results. Now, it's just a matter of whether NASA and ESA can keep it together long enough to get her up.
Land-based telescopes are gaining much ground, especially when it comes to data volume. The dataset for the LSST (Large Synoptic Survey Telescope) will most likely be measured in exabytes when all is said and done, and it simply isn't possible to send that volume of data home via telemetry. However, space-based telescopes most definitely have their place.
Two exciting ones are Planck, which will make extremely precise measurements of the CMB (Cosmic Microwave Background) and--if we're lucky--LISA, a gravity wave telescope that will open a completely new part of the universe to us. The science prospects for LISA are staggering, and it is simply impossible to build an interferometer with a 5 million km arm length on the ground!
That's a good point. Physics make frequent use of the (much) richer structure provided by the mathematics of complex numbers, quaternions, abstract vector states, you-name-it, but at the end of the day, we only measure real things, and the mathematics only helps to predict what we might (really) see.
That having been said, this doesn't really seem like anything new. Perhaps it adds some subtle structure, but I'll wait until I can read a paper...
Actually, there is such a theory, and it's 90 years old: Einstein's theory of general relativity. The metric of spacetime (it's curvature, and the thing responsible for what we call gravity) is determined by the energy-stress tensor, and the magnetic field DOES contribute to this tensor. In other words, a magnetic field does create a gravitational field. So does a gravitational field, for that matter. Any energy (and I'm including mass, here) creates a gravitational field.
Just as a pedantic physics aside---what other good are physicists for??---the "differing path length" explanation for the lift generated by an airfoil is not really cricket. There is no physical law requiring air that is "together" on the leading edge of the airfoil to come back together on the trailing edge. Now, it is true that air on the top edge will tend to follow the airfoil (see Coanda Effect)), but the net effect of both the concavity of the bottom edge and the convexity of the top edge is to direct air downward. It is this re-direction, along with conservation of momentum, that generates lift. It is true that the top of the wing is at lower pressure, as can be worked out from Euler's equations. But this is more of an effect than a cause. This page has some more information.
Sorry, that's just one of my pet peeves, because it replaces the basic reason for nearly all mechanics (Newton's 2nd Law) with a magical invocation of "Bernoulli's Principle." Cheers:)
Why on earth would you use a binary milestone for something like a performance metric? Measuring memory, storage, etc. in binary format makes sense as it is byte addressable. Measuring other quantities in anything but decimal is adds complexity.
Gmail, for instance, iirc. And I did actually think it was a hoax, since Google does have a bit of a sense of humour (PigeonRank!), but I was quite thrilled to see it was not!
Now I know why there were so many Chinese grad students in my lab! And I guess those secretive things on which they were working weren't sensitive papers, either...;)
It all depends on where you want to go with your career. If you really enjoy computer science, I'd recommend a maths degree, as this will take you a long way with theoretical computer science. That having been said, a PhD in compsci would probably be even better.
I myself have CS and physics bachelors, but my primary aim is at physics. I found the compsci degree helpful when I was doing work in particle physics, as I was writing tons of analytical code. Also, if you planned on doing development for government labs, an ability to create accurate models is a good thing, and physics will help with that.
Management, obviously MBA. I'd also consider a humanities (particularly English) degree; we always complain about the plight of the illiterate programmer/engineer/scientist. Well-spoken and clear-writing employees look good and go a long way. 3-4 years is a major commitment to polish up your writing, though! That having been said, I find I need the humanities to stay sane, so it's probably time well spent...
English probably is the first language of the editors, however. It is them to whom I was referring; I couldn't really care less if someone posts a comment without proper punctuation or what-not. Although I will use my stab-in-the-face-through-the-interweb device on anyone using SMSspeak. Do not tempt me.
I don't really have a problem with colloquialisms. I think they give otherwise uppity writing a little spirit--or at least a country twang! And, it's not as if slashdot is a literary journal. I do draw the line at the incessant spelling errors, and I cry havoc when I see fragments, run-ons, and sentences that clearly have their roots in a bad Turing test. It does seem that slashdot is pretty rife with these errors nowadays, and while it ain't Beowulf, it should at least give professionalism a passing glance.
I worked at CERN a couple of summers ago and saw the Cernettes and other physicsfolken band play at the Hardronic festival. I have to say, it's an otherworldly experience. CERN is one of those weird meshing places where there's an overload of talent. You'll walk out of a lecture on the Standard Model and hear someone in the next room roaring through a Beethoven sonata, or pass by the terrace and see the old hands of particle physics, maybe even a Nobel laureate, chucking around a frisbee. I found it extremely inspiring.
It's not surprising that it's no higher definition than an LCD since it was probably an LCD projector driving the picture, and probably a DVD feeding the projector...
What a fascinating idea! Since there are so many processes nowadays that are not precision-critical, a co-processor that could take advantage of a bit of indeterminism for a significant speedup would be more than worthwhile. This would even work in nicely with the Cell processor... units would be classified by precision. I think some work would have to be done on error-correcting coding, though.
Anyway, I'd mod you up, but I already posted:)
It would be impossible to compute the universe even if it were deterministic because you can never have a complete knowledge of the initial conditions. Even if you were to carry out the measurement for a spacetime hypersurface and measure, say, the energy eigenstate superposition of every system in the universe, there would still be unmeasurable phases that would affect the time evolution in a way you couldn't predict. That is to say, you could compute every possible solution (allowing for every possible phase difference), but you wouldn't know which one was right until you checked it, i.e., measured the universe again, so your computations were basically worthless!
I think "beta" is perfectly fine for services like Gmail, or for "new" OSS projects. Beta implies several things: an incomplete feature set, a possible instability, and "free". Google, being a company with proprietary source, might at any time decide to charge for Gmail, and I would expect that time to be when it transitions from "beta" to 1.0 or what have you. Well, it makes sense to me, and, frankly, its extended use doesn't bother me at all!
Probably you're right. I'm not about to work out the cross-section, because I have things to do this week, but for particles that energetic, and for as un-dense as your body is, I imagine the chance of an interaction would be pretty small. And even if there were an interaction, a typical particle could only dissipate something on the order of GeVs in your body... chump change. Now, you get lots of particles like this, you'll eventually fry. Do not stand in the beam of the soon-to-be LHC!
Because if you started out faster than the speed of light, you'd have an imaginary rest mass! Probably the one thing that makes it harder to get a date than by posting on slashdot -- not existing at all;)
Slashdot Mirror
It's absolutely non-trivial to do, but well within current capabilities. Just to blow your mind a bit, LISA must be sensitive to changes in arm length on the order of picometers... when the spacecraft are so far apart that round trip time for the light is 33 seconds! The only really tricky part in all of it is eliminating systematic errors from interactions with the LISA test masses and the spacecraft, but there has already been some testing done on test mass/spacecraft interaction, and they show the noise floor is low enough for good results. Now, it's just a matter of whether NASA and ESA can keep it together long enough to get her up.
Two exciting ones are Planck, which will make extremely precise measurements of the CMB (Cosmic Microwave Background) and--if we're lucky--LISA, a gravity wave telescope that will open a completely new part of the universe to us. The science prospects for LISA are staggering, and it is simply impossible to build an interferometer with a 5 million km arm length on the ground!
That's a good point. Physics make frequent use of the (much) richer structure provided by the mathematics of complex numbers, quaternions, abstract vector states, you-name-it, but at the end of the day, we only measure real things, and the mathematics only helps to predict what we might (really) see. That having been said, this doesn't really seem like anything new. Perhaps it adds some subtle structure, but I'll wait until I can read a paper...
Ah, I hadn't noticed. Lucky bastard.
Did you see the Tokaji in the last picture? A modder with exquisite taste in beverages... who knew!
Actually, there is such a theory, and it's 90 years old: Einstein's theory of general relativity. The metric of spacetime (it's curvature, and the thing responsible for what we call gravity) is determined by the energy-stress tensor, and the magnetic field DOES contribute to this tensor. In other words, a magnetic field does create a gravitational field. So does a gravitational field, for that matter. Any energy (and I'm including mass, here) creates a gravitational field.
I agree... I don't think I've ever seen a joke go whizzing past so many heads. As if slashdot is a reputable news source... MY GOD, THE CHILDREN!
Sorry, that's just one of my pet peeves, because it replaces the basic reason for nearly all mechanics (Newton's 2nd Law) with a magical invocation of "Bernoulli's Principle." Cheers :)
Why on earth would you use a binary milestone for something like a performance metric? Measuring memory, storage, etc. in binary format makes sense as it is byte addressable. Measuring other quantities in anything but decimal is adds complexity.
Gmail, for instance, iirc. And I did actually think it was a hoax, since Google does have a bit of a sense of humour (PigeonRank!), but I was quite thrilled to see it was not!
Now I know why there were so many Chinese grad students in my lab! And I guess those secretive things on which they were working weren't sensitive papers, either... ;)
I myself have CS and physics bachelors, but my primary aim is at physics. I found the compsci degree helpful when I was doing work in particle physics, as I was writing tons of analytical code. Also, if you planned on doing development for government labs, an ability to create accurate models is a good thing, and physics will help with that.
Management, obviously MBA. I'd also consider a humanities (particularly English) degree; we always complain about the plight of the illiterate programmer/engineer/scientist. Well-spoken and clear-writing employees look good and go a long way. 3-4 years is a major commitment to polish up your writing, though! That having been said, I find I need the humanities to stay sane, so it's probably time well spent...
English probably is the first language of the editors, however. It is them to whom I was referring; I couldn't really care less if someone posts a comment without proper punctuation or what-not. Although I will use my stab-in-the-face-through-the-interweb device on anyone using SMSspeak. Do not tempt me.
I don't really have a problem with colloquialisms. I think they give otherwise uppity writing a little spirit--or at least a country twang! And, it's not as if slashdot is a literary journal. I do draw the line at the incessant spelling errors, and I cry havoc when I see fragments, run-ons, and sentences that clearly have their roots in a bad Turing test. It does seem that slashdot is pretty rife with these errors nowadays, and while it ain't Beowulf, it should at least give professionalism a passing glance.
It made me feel extremely something! ;) And Kinard had chalk darts going for it...
I worked at CERN a couple of summers ago and saw the Cernettes and other physicsfolken band play at the Hardronic festival. I have to say, it's an otherworldly experience. CERN is one of those weird meshing places where there's an overload of talent. You'll walk out of a lecture on the Standard Model and hear someone in the next room roaring through a Beethoven sonata, or pass by the terrace and see the old hands of particle physics, maybe even a Nobel laureate, chucking around a frisbee. I found it extremely inspiring.
Does this sentence--and I use the word loosely--even parse in the Queen's English?
Or perhaps it does: Bastardising English
Thanks for one of the funniest responses on slashdot of all time!
It's not surprising that it's no higher definition than an LCD since it was probably an LCD projector driving the picture, and probably a DVD feeding the projector...
What a fascinating idea! Since there are so many processes nowadays that are not precision-critical, a co-processor that could take advantage of a bit of indeterminism for a significant speedup would be more than worthwhile. This would even work in nicely with the Cell processor... units would be classified by precision. I think some work would have to be done on error-correcting coding, though. Anyway, I'd mod you up, but I already posted :)
It would be impossible to compute the universe even if it were deterministic because you can never have a complete knowledge of the initial conditions. Even if you were to carry out the measurement for a spacetime hypersurface and measure, say, the energy eigenstate superposition of every system in the universe, there would still be unmeasurable phases that would affect the time evolution in a way you couldn't predict. That is to say, you could compute every possible solution (allowing for every possible phase difference), but you wouldn't know which one was right until you checked it, i.e., measured the universe again, so your computations were basically worthless!
I think "beta" is perfectly fine for services like Gmail, or for "new" OSS projects. Beta implies several things: an incomplete feature set, a possible instability, and "free". Google, being a company with proprietary source, might at any time decide to charge for Gmail, and I would expect that time to be when it transitions from "beta" to 1.0 or what have you. Well, it makes sense to me, and, frankly, its extended use doesn't bother me at all!
Probably you're right. I'm not about to work out the cross-section, because I have things to do this week, but for particles that energetic, and for as un-dense as your body is, I imagine the chance of an interaction would be pretty small. And even if there were an interaction, a typical particle could only dissipate something on the order of GeVs in your body... chump change. Now, you get lots of particles like this, you'll eventually fry. Do not stand in the beam of the soon-to-be LHC!
Because if you started out faster than the speed of light, you'd have an imaginary rest mass! Probably the one thing that makes it harder to get a date than by posting on slashdot -- not existing at all ;)