Spacetime may be curved, but it may also be flat

[J-Sun]

Not quarbonated (that's quantum carbonation, right there, is what that is). No fizz, no froth, no foam.

Drat! Einstein's right again!

(But we'll trip him up one of these days because we just gotta go faster than light. )

In all seriousness, these results are very debatable but, as they say, stimulating. It could easily not mean what it seems to mean, but I thought it was interesting enough to pass along.

 

[Metryq]

In a new study, researchers have failed to detect the fairies that allegedly make flowers grow. Scientists are calling this a win for a competing theory that gnomes are responsible. "Trolls are too big, and unicorns would eat all the flowers. So it must be gnomes," one scientist said. "There's simply no other explanation!"

 

[allmywires]

Froth? Really? Since science is usually about making things as simple as possible, I would've thought they'd let Einstein have this one...

I always liked the idea of smooth space-time anyway. It makes me think of a sheet of elastic. Very bouncy. Froth is just...gross.

 

[Metryq]

I always liked the idea of smooth space-time anyway. It makes me think of a sheet of elastic. Very bouncy. Froth is just...gross.

The "froth" idea runs completely counter to the "no ether" notion of Einsteinian Relativity, too. If there were a froth or ether, then one would have a universal reference.

However, the trampoline-like sheet of elastic makes no sense, either. Many pop science shows demonstrate the "warped space-time" idea of gravity by placing a bowling ball on a trampoline and then rolling a marble past it. This is circular reasoning. Imagine "freezing" the curved "space-time" shape made by the bowling ball—say, make the same shape out of hard plastic. Now take that up to ISS and place a marble anywhere on the surface, even the slope of the "gravity well." The marble would not be compelled to roll anywhere without actual gravity under the shape. So the analogy—and "warped space-time"—explain nothing. (Occam's razor—the idea does not explain gravity, it only removes the explanation by one step.)

The universe is not foamy coffee or a trampoline.

 

[Vertigo]

In fairness the analogy is only that. It doesn't represent the true three dimensional nature of the curvature showing only one of an infinte number of 'planes' of the curvature.

As for the froth, it hardly suggests an ether-like space. It refers to particles coming in and out of existence in vacuum, not hanging around to form an 'ether.' And I thought it had been succesfully demonstrated in experiments but I may be wrong.

 

[allmywires]

Argh, I was going to say Occam's razor would put the principle of froth to bed but I couldn't remember the name of the thing. My lecturer's always banging on about it (Occam's razor, that is, not gravitational froth).

Curved space-time is an approximation, yes, but it's fairly simple (even if it's technically wrong). Froth is unnecessarily complicated and apparently, according to this article, wrong. Since we don't really know which is right, we 'should' assume the simplest model, correct? Unless I understand Occam's razor wrong, that is.

Back to convolutional seismic interpretation revision for me...

 

[Vertigo]

The two aren't actually in opposition; only the smoothness of space time. And as J-Sun said at the opening it's too early to say either way yet. It is only a theory that the extremely short wavelengths of these photons should have been affected by the extremely small gavitational effects of the 'froth' of tiny particles. Personally I would not have expected such tiny particles to have such an affect but I'm no expert in this field and the scientist seem to think otherwise. I guess you could also argue that over such huge distances the interactions on different photons should have averaged out and you'd expect to see them arrive almost simultaneously. And note that they did not actually arrive simultaneously.

As an aside Occam's razor does not always work otherwise we'd still be holding to Newtonian Physics.

 

[Metryq]

As an aside Occam's razor does not always work otherwise we'd still be holding to Newtonian Physics.

Occam's razor does not state that the simplest explanation is correct. The principle is "entities should not be multiplied unnecessarily." In other words, don't throw in a kitchen sink just because you have one on hand. Since the "three body problem" is unsolvable with Newton's model, something different (perhaps more complex and maybe requiring a kitchen sink) was then required. It should also be noted that Newton's Laws do not explain gravity, they merely quantify it. And while General Relativity is clever, it also does not explain gravity.

I guess you could also argue that over such huge distances the interactions on different photons should have averaged out and you'd expect to see them arrive almost simultaneously.

One could argue that. One could argue many things. What was the timing between the pulses at the beginning and middle of their voyage? All we actually know is that three photons—ostensibly from the same source and perhaps launched at exactly the same time—arrived at Earth detectors only a millisecond apart. Anything more than that is a lot of chowder from one oyster.

"We found a fingernail at the scene of the crime!" How do we know it is related to the investigation at all?

How was the distance of 7 billion lightyears determined (redshift assumed to be due to the Doppler effect?), and does that distance influence the expected effect?

 

[Vertigo]

I agree Metryq, and to be fair the scientist only seem to be saying that it suggests or is an indication. Really they can say no more than that. It is interesting nonetheless.

 

[Metryq]

Vertigo, I'm familiar with the quantum foam idea and many of the other "spooky" ideas that are seriously contemplated by modern physicists. If you know, what actual observations suggested the foam in the first place? (Other than tenuous, mathematical virtual worlds built upon other equally tenuous virtual worlds, that is.) I'd be extremely skeptical of any claims to observations of sub-atomic particles popping into and out of existence. Once upon a time, a video camera mounted in the focus of a radio telescope was "picked up" as a complex, alien signal.

It seems quantum foam was first proposed in 1955, long before the MAGIC telescopes offered any "evidence." Maybe god shaves with it?

 

[Vertigo]

I wish I could give you a less vague answer than the following but...

There was a BBC Horizon documentary on a year or two back where this topic was examined and unfortunately I do not remember the details. I do remember that they created a vacuum better than deep space (which is not terribly difficult) and in that they observed particle activity or energy levels (the same thing I suppose) that simply should not have been present for the amount of matter actually in that vacuum and could only be explained in terms of particles coming in and out of existence.

Sadly I cannot remember sufficient details for a meaningful google on it.

Edit: Actually a quick further google suggests that I might be thinking of virtual particles arising from quantum perturbation or vacuum fluctuation (http://en.wikipedia.org/wiki/Virtual_particle) which is a measurable effect, and, though sounding similar to quantum foam, I confess I'm not sure it is the same thing.

 

[Metryq]

Ah, as I thought, Dungeons and Dragons:

As such the accuracy and use of virtual particles in calculations is firmly established, but their "reality" or existence is a question of philosophy rather than science.

So there's no empirical evidence. Also, Deep space is generally much more empty than any artificial vacuum. Yet there is always a reserved seat for the specters of the imagination:

Perfect vacuum is an ideal state of no particles at all. It cannot be achieved in a laboratory, although there may be small volumes which, for a brief moment, happen to have no particles of matter in them. Even if all particles of matter were removed, there would still be photons and gravitons, as well as dark energy, virtual particles, and other aspects of the quantum vacuum.

Dark energy and virtual particles. Right. That sounds a lot like paying off the national debt by minting a trillion dollar coin.

 

[Vertigo]

Ah, as I thought, Dungeons and Dragons:


So there's no empirical evidence. Also, Deep space is generally much more empty than any artificial vacuum. Yet there is always a reserved seat for the specters of the imagination:

Dark energy and virtual particles. Right. That sounds a lot like paying off the national debt by minting a trillion dollar coin.

To be fair just because there is as yet no direct evidence does not make it Dungeons and Dragons. There is a lot of evidence of the manifestations of virtual particles and I don't see other theories that explain all these manifestations.

As to deep space; the key word there is 'generally' and also what is meant by deep space. My understanding is that we can better the vacuum of most interstellar space but not that of intergalactic space. Though I may be wrong.

I have heard many scientists state that they hate the ideas of dark energy and matter, but until a better theory comes along they have to work with what currently fits the facts.

I think it is very unfair to label any unproven theory so derogatorily. All theories are unproven; that is what the word means. They are best attempts to fit explanations to the known facts and then produce predictions. It's just that many of the predictions of modern times are extremely hard to prove. You yourself are a proponent of some of the alternative, less well accepted theories, and there is nothing wrong with that. But they too are only theories. They cannot explain provably all the current facts any more than any other theories. That is why they too are still just theories. It is simply a case of which theories the majority of scientst choose to consider most likely.

 

[Metryq]

Let's be clear about Dark Matter and Dark Energy—they aren't theories with some unproven aspects. They are entirely ad hoc patches to existing theories that have failed in a big way. In fact, Dark Energy is a patch on top of Dark Matter.

I've heard the "we stick with this model until something better comes along" argument many times. The pretense that there are no alternatives or better explanations is either ignorance or willful blindness. When almost every astrophysical news story reports "unexpected observations" and astronomers as baffled, one really ought to wonder.