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## Comment Re:Absorbed not necessarily equal to electricity (Score 1)439

No, the worst case is much, much lower. The problem is that there are two different definitions of efficiency going on here. The 90-100% conversion to electricity means that 90-100% of the absorbed photons are turned into single electrons. This does *not* say that 90-100% of the energy in the original photons is converted to energy in the electrons. In fact, just as in all other solar cell devices, the photons initially create fast moving electrons, converting all of their energy. But most of that kinetic energy is lost to heat before the electrons can be extracted from the device and used to do work.

So, the take-home message is that efficiency can refer to number of converted photons, regardless of how much energy was lost to heat.

## Comment Re:Black holes are fiction (Score 1)314

You can derive the Schwartzchild radius using newtonian physics like clone53421 is claiming, and if that was what people were basing the existence of black holes on, then clone would be right. But it is just an accident that this derivation works.

If you do the derivation properly, using general relativity, you get the same result for the Schwartzchild radius. Though there are some interesting differences in how "radius" is defined in general relativity.

So, I'm sorry that the only derivation you saw was the incorrect classical physics one (which is used to motivate the result using simple math), but the answer is still true. But honestly, if you really thought that you were the first person to realize this problem with the derivation-- that none of the thousands of physicists to learn it since it was derived had noticed this glaringly obvious problem, then you are a monumental fool.

## Comment Re:metamaterials are just periodic structures (Score 2, Interesting)113

Metamaterials don't need to be periodic. They are made up of small (compared to the wavelength of light they work with) nano-fabricated structures, but even if they are randomly distributed it will have the desired effect. Just like both periodic structures (crystals) and amorphous ones (glass) have "normal" dielectric constants, so can metamaterials.

Some people say "periodic" when they just mean "made up of small stuff". If that was your complaint, then I challenge you to find something with any index of refraction that isn't "made up of small stuff."

## Comment Re:Relitivity (Score 1)383

Assuming you weren't being snarky, he's just speaking in the language of physics. Don't take "observe" literally-- he just meant when the light reaches us. If you were being snarky, then when you close your eyes, you'd be likely to be eaten by a grue.

## Comment Re:Relitivity (Score 1)383

Yes, but that's meaningless, and moreover you don't have to speculate. If the light has not reached us yet, then the two events (here&now and the ka-boom) are not causally connected. That is, they are "space-like" separated. You can show that there exists a reference frame with any time duration between two space-like separated events. So, in some reference frame, I'm typing this post *after* the light from the supernova has occurred. In another frame, I'd have to wait a billion years for it to happen. And all choices are equally arbitrary, including yours.

## Comment Re:Relitivity (Score 1)383

Perhaps it would help if I logged in... we can all be glad that ACs cannot mod things up.

## Comment Re:Relitivity (Score 1)383

No, he would never say the last line. Time travels at the speed of light. When we see it, it is the same instant of time when it exploded. Or more formally, the two events become causally connected the instant we see the light.

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