Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Comment Re:"because he was already right the first time".. (Score 1) 98

It's not that they can't both be right (in fact, both are correct, insofar as calling a theory "correct" makes sense in physics), it's that they break down in certain regimes. This is the absolute last thing from surprising: every single physical theory we know of so far breaks down at some point. Newtonian mechanics breaks down at high speeds (relative to c). Classical mechanics breaks down in the quantum limit, and is replaced by quantum mechanics. Quantum mechanics breaks down in the relativistic limit (and is replaced by quantum field theory). Most QFT breaks down at high energies, as we can only solve it in the pertubative low-energy limit.

In the case of GR and quantum mechanics, that's exactly what happens. At low energies, the two work together fine. It's at high energies and short length-scales where the two fall apart (no surprise, as again, both theories were formulated from the low-energy behavior, which is the regime we can perform experiments/observations in quite easily). This is why people are looking for some unified theory that would include both theories in the low-energy regime, and at the same time would work at high energies (this has already been done with electrodynamics and the weak force: at high energies, they become unified through the electroweak interaction). String theory, loop quantum gravity, etc. are all such attempts. So far, we've not been able to perform experiments that would be required to confirm any of them.

Comment Re:Not sure of the importance (Score 5, Insightful) 51

AFAIK there are no directly anticipated applications. However, knotted fields are incredibly cool and interesting physical objects (if you're into that kinda thing). Of course, formation of novel magnetic fields could have applications in fusion research or quantum computing, but the idea behind theoretical physics research like this is to figure out how things work, and let the engineers and applied physicists figure out the applications (if they exist) later on. It's worked pretty well so far. And confirming that nature actually works like it's been predicted to work is a worthy endeavor in and of itself, even if it turns out to have no applications at all.

Comment Re:Wrong business model (Score 1) 278

The target demographic of the Rift may have been PC gamers at one point. That stopped being the target after it was bought by Facebook. I mean, it's frackin' obvious that Facebook didn't spend 2 billion dollars on a PC gaming peripheral. No one would. The fact they threw in a (not optional) XBox controller into the package really hammered that point in hard.

Comment Re:Correction: not "$200 to $400 range" (Score 1) 278

Or, guy with unfinished product has no idea of cost but needs to get investors to keep giving him money so he can finish building it.

He said this after Facebook bought his company for US $2 billion. He didn't need more money. He said this after he'd made (and sold) several prototypes. He had a pretty good idea of what it would cost. The actual price is after Oculus VR added things it didn't need, like an XBox controller. And of course this is the price set after it started being manufactured in bulk (which should have driven down the price considerably, yet apparently didn't).

Comment Re:What about Scientific Linux? (Score 1) 62

The mention of the ISS was not accidental: Scientific Linux has, in fact, been installed there. As a matter of fact, in experimental physics the OS often is mission critical. You need something to run the detectors, after all. While at a low level that usually means firmware or ASICs, at the level of the experimenter that typically means using a computer, with a rather conventional OS installed. Stability there is vital, as a crash could mean (worst case) damage to the equipment, or best case some usually rather expensive downtime for the experiment.

Comment Re: Cut to the chase (Score 1) 134

No, because the Planck time is 10^-44 seconds. We have trouble measuring events that occur within 10^-20 seconds (we can do it, but only indirectly). 10^-44 is so vastly below any of our detection thresholds that events that occur in that timespan may be literally immeasurable, simply due to practical experimental problems.

Comment Re:If gravity involves an interaction between mass (Score 1) 134

That is not what's meant by gravity being quantized. Quantum gravity would mean the gravitation interaction between particles is quantized: i.e. if particle A pulls on particle B (and vice-versa), the energy exchange between them occurs in discrete packets. The alternative would be that the gravitational forces between them are a continuous interaction, so that A pulls on B to change the energy state of both constantly. To use an analogy: the former is like an object rolling down a staircase, where the objects level jumps as it falls down a step, while the latter is like a ramp, where the object's level takes on all continuous values of the ramp.

Comment Re:Its laugh track is a crime against humanity (Score 1) 406

Wait a moment. There's at least EIGHT people who appear twice in that photo, and it's not a simple stitch together either. Check it out. Definitely the "live studio audience" isn't all that it's made out to be.

Pretty sure it is just a simple stitch together. The photos were taken not only from multiple angles but multiple locations as well (the opening in the back on the left side of the picture is the same as the opening the second in from the left, just from a different angle).

Comment Re:The Facts (if anybody is interested) (Score 5, Interesting) 161

-> it looks like this motors are only a bit off in the laboratory test (they are almost EURO 6 - but not without the cheat)

"Only a little bit off"? They emit 10-40 times as much NOx as they're supposed to (EPA source[PDF warning]). That's not "a little bit", that's "actually a fuckload".

-> EURO 6 from VW is fine (see http://www.theicct.org/nox-con...) as other German manufacturers, but some others have problems.

The linked paper only shows test results from a single VW vehicle. Not enough to say anything about VW's general compliance or lack thereof.

Comment Re:US got bored forcing their laws on other countr (Score 1) 162

That is completely legal.

However US courts claim that US law is to held up "in Europe!" which makes the teacher lose his job.

We europeans lough our asses off about such stupidity.

I would laugh with you, if that's what actually happened. Except it's not (unless you can provide a contrary link). What actually happens (on multiple occassions, apparently) is that the teacher was fired for violating school rules. Not for violating US law (because in fact a teenager drinking wine in Paris is not a violation of US law.). The teacher was responsible for following the schools rules, the teacher failed to do so, and the teacher was fired/punished for doing so. The only involvement of the courts (AFAICT) is that they agreed the school could fire the teacher.

Now, of course "zero tolerance" rules are incredibly stupid, but that's more of a low-level institutional problem than a US law problem. Note that there actually are a couple of US laws that apply to US citizens even outside the country: for example, laws against pedophilia (to prevent sex tourists from going abroad and having sex with 12-year-olds or younger). Drinking abroad, however, is not against US law.

Slashdot Top Deals

A good supervisor can step on your toes without messing up your shine.