swansont

Wasn't in my stockpile, actually. Spontaneous smartassery.

The top of the visible is a tad smaller, though — 400 nm is about 3.1 eV, and 700 nm is about 1.75 eV, so the efficiency from that standpoint can be above 50%. Normal fluorescent bulbs have an overall luminous efficiency of around 10%, but incandescent bulbs are somewhere around 2%. Incandescents waste a lot of energy in the IR. (Keep in mind in evaluating those numbers that the ideal white light source has an efficiency of 35.5%, because luminosity is defined in terms of light at 555 nm, where the eye is most sensitive.) So the "relatively small" here has to be taken in context — even though 10% doesn't seem very efficient, it's still five times better. http://en.wikipedia.org/wiki/Luminous_efficacy One advantage that LEDs would seem to have over fluorescent bulbs is the ability to choose the bandgap rather than rely on a molecular or atomic transition, usually mercury (at 254 nm IIRC)

The relevant factor is the bulk modulus, and for metals it's usually in the 100's of GPa. http://en.wikipedia.org/wiki/Bulk_modulus

I split this from the gravitons thread, since it is OT for that. Depending on how this goes, it may end up in speculations. smooth, please lose the attitude. It is a barrier to constructive discourse.

When did Singer become a "climate physicist"? Has he done any research and published any peer-reviewed articles? Anybody can publish books and op-eds. And Singer has flip-flopped his stance; a few years ago it was "there is no warming" and now it's "there is warming and it's not anthropogenic — it's unstoppable." His consistent position has been "less/no government involvement" but that's ideology, not science.

If only we had some April fuel to warm things up.

And as you showed a few posts back, 2008 is a data point is somewhat above the trendline. Once you distill the discussion, that's all that's been noted here. Nothing more to see. Let's move on.

It depends on how the shift happened, because energy, momentum and angular momentum are conserved — the quantities would change with a shift in the moon's orbit. The response of the earth would depend on what actually happened. If the moon were simply in a different orbit, then there would be a difference in the strength of the tides and probably in the amount of precession and nutation of the earth. ——— And to whoever hacked the editor: Oh, you magnificent bastard!

What breach of contract? If I tell Kary May Kosmetics that I (and others) won't use their products until they stop testing them on unicorns, what contract is potentially being breached?

The events to which insane_alien refers are cosmic rays, which can have a much higher energy than the LHC will achieve.

Note that academia isn't the only avenue open to you for doing research. Though government and industry will likely be applied research, rather than "basic" research.

How is this different from negotiating a lower price for a product because of the existence of competition?

Incandescent depends on heating, and emission of a spectrum approximating a blackbody, so a fair fraction of the energy is outside the visible range, giving rise to the "all heat but no light" misnomer. Fluorescent relies on a discharge to excite/ionize a material, and the photons emitted (usually in the UV) to excite a material that (wait for it) fluoresces, i.e. emits lower-energy photons. The "wasted" energy is often smaller, because the difference in energy from the UV down to the visible can be made relatively small. LEDs excite electrons across a bandgap in a semiconductor, and they emit photons when the drop back down. Also can be made to be very efficient, if the excitation closely matches the photon energy, so much of the input energy is delivered as photons.

Bingo. What I was alluding to a few posts ago, but stated better.

I suspect the problems arise because measurements are being made in different reference frames, and you are not free to just jump between them in your analyses. I can't vouch for the veracity of the site, but I found http://www.mathpages.com/rr/s7-03/7-03.htm "Thus when we say "the gravitational acceleration goes to infinity as our radial position approaches 2m" we really mean that the amount of acceleration required to boost us into a hovering frame goes to infinity"

Any problem you'd have with gravitons you'll have with the electromagnetic force as well. And perhaps worse with force carriers that have mass — do they fail to work outside the event horizon, but in a region where they are gravitationally bound and would be unable to interact with other particles at a greater r? I think one needs to consider two things — the differences between how virtual and real particles behave, and that GR is a classical theory, so any introduction of quantum effects is potentially incompatible and may lead to erroneous conclusions. I'm not a GR person, so I don't know where exactly those pitfalls are located. But that leads to a question — are we sure that gravitons wouldn't be emitted at the event horizon?

You're looking for the physics definition of time, and yet you insist on looking in a dictionary. My suggestion of looking up "coincidence" would point out that the dictionary definition is basically opposite that of the physics definition, demonstrating that the dictionary is not a technical resource. Which has been stated a number of times before. Is energy just a consideration? Something need not be physical to be real, and it can still be something other than a "consideration." You're looking for metaphysical answers to questions. Science isn't going to give them to you. You said they were composed of motion, which is clearly, well, laughable. http://www.nist.gov/public_affairs/releases/mercury_atomic_clock.htm The optical oscillations of the essentially motionless ion are used to produce the "ticks" or "heartbeat" of the world's most stable and accurate clock. http://physicsworld.com/cws/article/print/22097 The ideal frequency reference would be a single, motionless atom, unperturbed by any interactions with other atoms or the environment. http://whyfiles.org/078time/index.php?g=2.txt The cold, slow-moving, atoms are measured in the microwave chamber on the way up and back down, using the same general technique we've already seen. The improved precision results from the reduced Doppler effect and an increase in measurement time. i.e. there is an improvement in making the atoms move slower. Motion is not the basis of the measurement. I keep pointing out that this is a false dichotomy. The oscillation is in the wave function, which is not real. The atoms are placed in either one state or the other. But this is QM, so it's really not profitable to try and glean classical meaning from what's going on.

I don't think we're at the level of delving into legal definitions here. I think the idea here is one of ethics, as in the ethical equivalent of blackmail. It's fairly obvious boycotts are legal. You don't need any reason, good or bad, to not shop at a particular store. You can not shop at a store because you don't like their color scheme, or because you think their checkout clerks are ugly. An organized boycott is, in one sense, an advantage to a business, because they know what behavior is keeping customers out, and don't have to guess. They then get to decide whether the proposed change is cost-effective, or whether an ad campaign to spin (or unspin) the story is a better option, or maybe a third course of action is warranted.

Once you account for this, then you have to add in the artificial impact of schedule. If it's assumed that the winds will aid/delay you by 45 minutes, and the actual delay is less, the plane will slow down as it approaches the destination, to fit into the scheduled landing slot. (I recall a trip from London to Wash DC, where were 30+ minutes ahead of schedule as we reached North America, and we "burned" it all doing a slalom track across the northeast US and circling Dulles airport. Landed "on time")

Yes, I'd say the two rulers here have different lengths.

As far as I know, yes, but gravity is very weak — we haven't ever detected gravity waves because they are so hard to measure. So this severely limits the rate at which the dark matter would be able to shed any energy.

But it does get smaller, when you go to the other reference frame. The two rulers are measure in exactly the same way, and yet you get two different answers, depending on which frame you are in. But I thought your claim was that none of this was true. And yet you link to an animation that demonstrates length contraction using time dilation.

Not necessarily for the public good. It could simply be the feeling (correct or not) that the company screwed you. But it doesn't matter, because people aren't under any obligation to agree with you, either. I don't think so. You are making others aware of the situation — it's advertising, which businesses certainly do. They try and convince us to buy their product. A boycott is an effort to convince you not to buy their product.

Well, to be fair, I can see how some here would take "you seem to have a misunderstanding on how an atomic clock works" to be an attack. I also know on whom they would bet, if the contest were between the two of us, on who knows more about atomic clocks. An atom is not "composed of motion." It is composed of neutrons, protons and electrons. One can argue whether the electrons are in motion or not — QM describes a probability function of where they might be found, but that's beside the point. I said that the atomic clocks don't depend on the motion. Motion adds time dilation effects — the best clocks use atoms or ions that are as close to motionless as possible. In a standard atomic clock (Cs or Rb), you use the hyperfine splitting of the ground state — put half of the atoms in one state, and the other half in the other state. Because of the peculiarities of quantum physics, the ensemble is in a superposition of the two states, and behaves like it is oscillating between them. But none of that implies any physical motion of the electron. The difference between the states is the spin orientation of the electron. What is the definition of "coincidence" in the dictionary vs its use in science (particularly physics)? You're hung up on "physical" for some reason. Something can be real without being physical. Is energy real? Is it physical?

http://en.wikipedia.org/wiki/Joseph_Newman_(inventor)