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Phigure wrote:

kay wrote:

alphacat wrote:

alphacat wrote:This is pretty interesting stuff. Seems like they might be on to something important here.

https://www.simonsfoundation.org/quanta ... m-physics/

Meh. http://4gravitonsandagradstudent.wordpr ... lly-words/

I'd thought the original article made those points reasonably clearly?

yeah it does and i dont think it makes it any less interesting, its just a matter of generalizing/modifying it to make it work with the actual standard model

Exactly!

A little fun anyone?

http://www.aptitude-test.com/mechanical-aptitude1.html


I got 100%, but 5 and 6 I guessed on. So really only 86.7%.

It didn't look like any other than A were even doing anything in #5.

It was pretty simple though.

Calculators for simplicity, but no formulas or equation solvers for fairness.

Currently Working on Einstein's Riddle. Three empty rectangles left. Only animals to spare.
http://www.aptitude-test.com/einsteinsriddle.html

...

nerd

My bad, I was two tiles off.
Instead of submitting the answer my dumb ass clicked to see the solution, and then didn't notice its own mistake.

that video is completely unscientific trash tbh

related videos from the same user:
wanna own? get a life
god is in the neurons
athene's theory of everything

Didn't watch, but the title of the video doesn't seem to have anything at all to do with matters of Physics.

Negative absolute temperatures debunked:

http://web.mit.edu/newsoffice/2013/its- ... -1220.html

The main claim of such experiments is that they are able to produce systems with negative absolute temperatures, or temperatures below 0 degrees Kelvin.

Is it not wrong to say that negative numbers are smaller than positive ones? Aren't they of equal size? Is that not inherent and unchanging regardless of physical convenience, for lack of a better word?
You can't add negatives and expect positives, right? So why did they expect to get more out of input energy? You'd need negative input for a negative output. That's even what an equation would say. Isn't it?

jesslem wrote:

The main claim of such experiments is that they are able to produce systems with negative absolute temperatures, or temperatures below 0 degrees Kelvin.

Is it not wrong to say that negative numbers are smaller than positive ones? Aren't they of equal size? Is that not inherent and unchanging regardless of physical convenience, for lack of a better word?
You can't add negatives and expect positives, right? So why did they expect to get more out of input energy? You'd need negative input for a negative output. That's even what an equation would say. Isn't it?

The article briefly explains why negative absolute temperatures would have meant a system that was hotter, not colder than one with a positive absolute temperature near zero. You can also look it up on wikipedia.

Entanglement, wormholes and possibly gravity:

http://web.mit.edu/newsoffice/2013/you- ... -1205.html

kay wrote:

jesslem wrote:

The main claim of such experiments is that they are able to produce systems with negative absolute temperatures, or temperatures below 0 degrees Kelvin.

Is it not wrong to say that negative numbers are smaller than positive ones? Aren't they of equal size? Is that not inherent and unchanging regardless of physical convenience, for lack of a better word?
You can't add negatives and expect positives, right? So why did they expect to get more out of input energy? You'd need negative input for a negative output. That's even what an equation would say. Isn't it?

The article briefly explains why negative absolute temperatures would have meant a system that was hotter, not colder than one with a positive absolute temperature near zero. You can also look it up on wikipedia.

That wasn't what I was talking about. I misquoted on second look though.
From that quote, it goes on to say that in these systems were supposed to be able to be able to do more work than the heat energy supply would permit for regular systems. I looked a little further into the entropy equations and I gathered that the temperature, while not solely responsible is a factor in the calculation. And this essentially means that a negative temperature value would 'go into' the input energy value more times than its positive counterpart, and to me that just doesn't make sense. Not unless it's being given some kind of anti-heat, or better yet, losing heat, and that still doesn't make less sense.

Furthermore, the fact that there are more particles in higher energy states 'burning' the same amount of input heat suggests that the system is less efficient doesn't it?

tl:dr

I wasn't questioning the conclusion of the paper, I was questioning the hypotheses that brought it out.

I believe, and I could be wrong, that the assertion was due to a belief that negative absolute temperatures represented an unconventional distrubution of energies. So it wasn't actually negative in the real sense. It was also an unstable state so it would want to release energy to return to a stabler, lower energy state. But, because you reached the unstable state by pumping out energy out of the system, it made it seem as though you were pumping energy out, and then the system was putting out more energy on top of that.

Makes absolutely no sense, but that's what happens when you:
a) Follow maths blindly, and
b) Forget the initial assumptions that your maths/conjecture is based on

Hawking - No Black Holes (edit: if no event horizon)(mb muncey, i was at work)

Interesting read:
http://www.nature.com/news/stephen-hawk ... es-1.14583

He said black holes don't exist if theres no event horizon, not that black holes don't exist.

I think he's postulating that black holes don't exist as we currently define them, because the current definition implies an event horizon ie a point of no return. It seems like a logical step from all his work on black hole evaporation and the apparent quandary of the distruction of information.

kay wrote:I think he's postulating that black holes don't exist as we currently define them, because the current definition implies an event horizon ie a point of no return. It seems like a logical step from all his work on black hole evaporation and the apparent quandary of the distruction of information.

^ +1