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Comment: Re:And the US could turn Russia into vapor (Score 1) 878

by reve_etrange (#46586193) Attached to: Russian State TV Anchor: Russia Could Turn US To "Radioactive Ash"
Fair enough. It's just that since redeeming public debts has no impact on private net financial assets except for the loss of future interest income, any consequences of a drastically larger QE program would probably have more to do with institutional risk assessments than, say, consumer price adjustments.

Comment: Re:Possible exception to the "law"... (Score 2) 194

the assumption that the current physical laws and constants were true then. By definition, they weren't - the four fundamental forces did not assert themselves until a finite period of time

If they didn't "assert themselves," does that imply that they did exist? I think that this way of speaking is a little confusing, because we believe that current "laws" represent special cases of more general laws, rather than different laws entirely.

If nothing had mass at the instant of the Big Bang, how does Einstein's theory of Relativity apply? Objects become infinitely massless as their speed approaches c?

Massless particles inherently move at c. They can't be accelerated or decelerated because they have no inertia, although they do have momentum.

As far as we know, this was just as true right after the big bang. Particles, or field excitations or whatever, had no mass, and moved at c. They did have energy, and an energy density, and therefore were gravitationally attracted. This attraction would be described by quantum gravity, instead of General Relativity.

Once the particles acquired mass via the Higgs mechanism (probably at or about the same time that the modern-day forces became completely separated), the universe was still an ultra-hot quark plasma, so the newly massive particles still moved very rapidly. Just not at c.

Comment: Re:Just a thought... (Score 1) 194

And even if there was a problem with space expanding superluminally, inflation would be the least of our worries, as we would need another explanation for the size of the observable universe. (We can see objects at ~40 billion light-years distance, even though the universe is only 13.8 billion years old).

Comment: Re:the "laws" of physics (Score 1) 194

Are you proposing that the laws change randomly or something?

If the laws of physics change with time, then what we thought were the laws aren't actually the laws, but rather the actual laws with parameterized time. It might make some experiments more difficult, but there is no philosophical conundrum. Actually, this idea is already implicit in lambda-CDM ("standard model" of cosmology), where there is a time-dependent "scale factor" in the Friedman equations.

Comment: Re:Well, yeah... (Score 1) 194

Only matter and radiation must move at or below the speed of light. Relativity poses no limit on the relative velocities of objects, provided these velocities are acquired via the expansion of space. During the inflationary epoch after the big bang, space itself (probably) expanded at a rate faster than the speed of light. We think this process magnified small fluctuations, which nucleated the aggregation of matter into galaxies, that it separated different regions of the universe after they were in thermal equilibrium, and that it diluted away rare particles such as magnetic monopoles.

The whole idea of an "observable universe" is predicated on relative velocities greater than the speed of light. The event horizon at the edge of the universe exists because beyond that distance space (and the objects in it) are moving away from us at a speed greater than that of light, resulting in the causal separation of regions of the larger universe.

Actually, we know some rapid expansion must have occurred, because we can see objects which are apparently ~40 billion light-years away, even though the universe is only 13.8 billion years old.

Comment: Re:Possible exception to the "law"... (Score 1) 194

The parent may have confused you with the choice of terminology. All particles, including the Higgs boson, are excitations of fields which permeate all spacetime. These fields have existed at least since the big bang. There is no need for any of them to have "come first."

It is true that today there are many sorts of massless particles, and it is very likely true that cooling after the big bang led to some rearrangements of the quantum fields (called the 'Higgs mechanism') which led to many particles acquiring mass or becoming more massive.

Comment: Re:Possible exception to the "law"... (Score 2) 194

First, massless particles, like the photon or graviton, don't go past c. They go exactly c. Anything going faster would be a tachyon, which isn't like any of the massless particles we know. BTW, these BICEP2 results seem to confirm the existence of gravitational waves, and thus of gravitons. Otherwise, I would have said "supposed gravitons" or something like that.

There is also the concept of tachyonic fields, which are fields whose particles have imaginary mass. The Higgs before symmetry breaking occurred is an example, but despite their name, excitations of tachyonic fields propagate at or below the speed of light.

In short, you can't accelerate even massless particles past c. Nevertheless, objects can have faster-than-light relative velocities as long as these are acquired via the expansion of space.

Comment: Re:An illusion (Score 1) 194

The proposed acceleration is not at the "edge" of the observable universe. It is (apparently) everywhere that matter is not bound by gravity. Inflation, which is most likely quite distinct from our current expansion, was likewise everywhere in space during its brief moment after the big bang.

In any event, the universe is very close to 13.8 billion years old, yet the farthest objects we can see are some 40 billion light years away.

Comment: Re:An illusion (Score 1) 194

I think most cosmologists believe in an infinite universe, wherein inflation has led to many "bubble" observable universes due to the finite speed of light and finite age of the universe. See chaotic/eternal inflation.

The observable universe is actually much larger than ~15 billion ly. The farthest objects we can see are at extremely high redshifts implying distances of about 40 billion ly. You may note that this is greater than the age of the universe times the speed of light.

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