Dark Energy/Zero-Point Energy/Tesla

[KrazyHorse]

Organic = bio
Chemistry = chemistry


Same difference.

[Az]

Organic = bio

let's return to the topic, ok?

[pchang]

Adding EM stuff into cosmology was from Hans Alfven. This is backed up with plenty of experimental evidence. Cosmologists don't like it because they have a hard enough time with just gravity.

[DanS]

a) I don't think that Tesla was even close to the smartest man of his time

Even close? Hmmm... How to judge? He may not have been the smartest, but he is widely regarded as one of the greatest men of his time, among Edison, Bell, Einstein, Pasteur, Marconi, etc. He is hailed especially loudly in the slavic world.

[Dauphin]

Originally posted by pchang
Adding EM stuff into cosmology was from Hans Alfven. This is backed up with plenty of experimental evidence. Cosmologists don't like it because they have a hard enough time with just gravity.

As you probably know, Alfven also thought that the Big Bang theory was not required.

[pchang]

Yes. But that is not sufficient justification to ignore EM effects in cosmology. Why not have the Big Bang AND EM?

[TCO]

how's your neck, Bill? Imran was really worried about you...

[TCO]

What happens if a watcher sees a particle making a racist remark?

[TCO]

Originally posted by KrazyHorse


Same think happened to the undergrad particle course I took.

Part of the reason I decided on CM...

That and he fact that HE theoists have no ****ing clue what they're doing.

Well...plus CM is just cooler. Very crew-cut scientist cool.

[TCO]

Originally posted by Ramo
Well, the ZPE comes from the idea that over short times, there's uncertainty in energy (which is a result of the Hamiltionian operator not commuting in general with an arbitrary observable, rather <[H,A]> = i(hbar)d< A>/dt, if you were curious ), causing particles to pop in and out of existence. So, there's a vacuum energy density due to these particles that permeates space. Because pressure can be thought of as -dE/dV, and because energy actually increases when the volume of a given vacuum increases, the pressure due to the vacuum energy density is negative. Now, Einstein's field equations impose a dependence on pressure as well as mass, so imply that the vacuum energy density, in the absence of mass or positive pressure, would cause an outward acceleration.

ZPE is a form of "dark energy." Another form is called quintessence, which is somehow based on temporal variation some scalar energy field, and something I know nothing about.

Dark matter is the stuff theorized to account for what's seen as missing mass.

I've never heard of a Telsa energy.

I'm used to hearing ZPE referred to such things as the kinetic energy of an electron (in it's lowest state) or the kinetic energy in a lowest state of vibration in a H2 molecule. Those don't have anything to do with particles popping in and out of existence, but are basic things that you can get out of the time independant Shroedinger's equation.

[alva]

Ban him!!!

[TCO]

Originally posted by KrazyHorse
The difference between dark matter and dark energy is that dark energy increases when you increase the volume of the universe. Dark matter does not. This has serious consequences.

Dan, the reason that we don't think that dark energy is the vacuum energy is that the vacuum energy is something like (depending on who you believe) 10^40 to 10^120 times too large.

Supersymmetry "fixes" this to the extent that it kills off the vacuum energy entirely, leading to a zero cosmological constant (zero dark energy density). The idea that you'll somehow use supersymmetry (with some sort of enormously tiny supersymmetry-breaking term, I suppose) to erase all but a very tiny bit of the vacuum energy in order to properly explain the observed cosmological constant is called fine-tuning. Physicists don't like that. Even more troubling, the need to fine-tune crops up over and over again in particle physics. For instance, the hierarchy problem.

The reason this happens is that particle physicists are idiots.

Yeah, ****ing yeah!!! BTW, there are still very basic effects in magnetism and the such, where we can not get (first principles) theory to explain experimental results. Heck BCS theory was hard enough...

[TCO]

Originally posted by KrazyHorse
As to the Tesla thing, if Tesla postulated anything like that without evidence then his ideas were just as useless as were the classical atomists'. Without solid experimental evidence for your flights of fancy you're simply practicing intellectual masturbation. Without some sort of mathematical framework it's not even all that intellectual.

Yeah! Rickover would be proud!

[Dauphin]

Originally posted by TCO


I'm used to hearing ZPE referred to such things as the kinetic energy of an electron (in it's lowest state) or the kinetic energy in a lowest state of vibration in a H2 molecule. Those don't have anything to do with particles popping in and out of existence, but are basic things that you can get out of the time independant Shroedinger's equation.

That's what I have always heard refered to as the Zero-Point Vibration Energy. But that's splitting hairs I guess..