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[MonkeyHead]

You can't destroy energy, but it can and will spread out thinner and thinner, until eventually every little photon is flying off in some trajectory that has a 0% chance of ever intercepting a black hole.

Yes you can. CMB photons, and any photons travelling through expanding space are continually being redshifted = losing energy. It's not a matter of energy density going down, but energy of individual photons dissipating.

Conservation of energy is a concept that is undefined on cosmological scales. Here's a good article about it: http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html

My own understanding of that particular situation is that the energy of the photon is possibly being transferred into gravitational potential in some way... I suspect I need to read up full on this to make a more significant comment than that though.

[Sergarr]

Wait, if on large scales there's no conservation of energy, doesn't that mean you can imagine a process that will create energy out of nowhere?

EDIT: Ah. This is an interesting article. I think it said that because time and space are bounded together, then concepts which rely on one of them become relying on all of them. Or something. This is a little bit above what I can understand easily (maximum sarcasm).

[MonkeyHead]

Wait, if on large scales there's no conservation of energy, doesn't that mean you can imagine a process that will create energy out of nowhere?

Well, in its crudest sense, I suppose that is one explanation for how the universe might have come into being. Not a good one though

[MaximumZero]

Once upon a time, there was nothing. Then, it blew up.

[kaian-a-coel]

Once upon a time, there was everything. Then, it blew up.

fixed (maybe?)

[Putnam]

Yeah, there never really was nothing. Everything has always been there, at least as long as time has been a thing.

[iceball3]

Yeah, there never really was nothing. Everything has always been there, at least as long as time has been a thing.

Or, at least, there's no evidence of nothing, to say the least.

[Darvi]

You can't prove nuthin'

[Sergarr]

Yeah, there never really was nothing. Everything has always been there, at least as long as time has been a thing.

Or, at least, there's no evidence of nothing, to say the least.

The evidence of nothing is nothing i.e. nonexistent

[iceball3]

Yeah, there never really was nothing. Everything has always been there, at least as long as time has been a thing.

Or, at least, there's no evidence of nothing, to say the least.

The evidence of nothing is nothing i.e. nonexistent

Well, there could be evidence in the form of something that forms an effective frame against reference against nothing, which is something referring to nothing. I think.

[Scoops Novel]

Quantum chesire cat, discuss

[TheDarkStar]

NASA found that a variant of the M Drive works: news article and NASA report.

[Solifuge]

NASA successfully tests a thruster based on the EMDrive, which doesn't require propellant, doesn't produce exhaust, and operates on electrical charge alone.

"Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma."

That makes them the third party to confirm that the drive is not only plausible, but that their take on the design generates thrust, despite being a closed system. And I am really excited about it.

PPE: Ninja'd, but I remain excited.

[TheDarkStar]

[SCIENCE INTENSIFIES]

It was inevitable.

[Sirus]

If my reading of the article was right, it's a very, very low-power thruster mostly only good for satellites. Possibly space probes as well. No starships yet, sadly :/