Recent content by Enquerencia

I am certain that my confusion here rests in a misunderstanding on my part and not in a mistake having been made by countless physical theorists. Nevertheless, I have had a hard time wrapping my head around it. Here is the crux: We observe that light from distant objects is more redshifted...

Yes, this is the context in which I was trying to imagine an infinite universe in a finite space. I had a pretty hard time with it. However, that's not to say that I came to believe that it was impossible, I just couldn't wrap my head around it completely. I still have a lot to comprehend, even...

Wow, that was awesome. I didn't mind at all hearing you explain some of the things I basically already understood, because you explained them very concisely and elegantly. I feel I understand them better now than I did before. General relativity explains that mass and energy bend the curvature...

I've really been trying very hard to wrap my head around this lately, and i apologize if I seem to be!having difficulty asking the question in a way that makes sense, but if the universe has a measurable size (I did catch that "minimum size" detail, which I take to mean that it may not have a...

I'm talking specifically about whether the universe flat and infinite, or if it is curved, perhaps even closing in on itself like a sphere such that a long enough journey in any direction would end at its beginning. Or if it is finite, with an edge. I read somewhere that the matter in the...

It may be that nothing is, or even can be empirically known about exactly how big our universe is, or the shape of its geometry (flat, round, etc.), but what are some basic, provable facts that can be used to work out a theory or to debunk one? I know this is a very broad question. I have come...

For fictional time travel, and causality in logical but fantastical terms, there are some really good Futurama episodes that deal with it really well. I thought GoT handled it right. In a magical universe, sure. It works. Edit: My favorite instance of bootstrap time travel is in Bill and Ted's...

There was a really interesting article I read some years ago, I can't begin to find a link now, that elegantly explained the inherent paradox of time travel. It involved a man arriving at a point in time, sticking around for a length of time and then traveling back to that first point in time...

Is there a "lounge" type forum within PF, or another forum you can recommend for purely speculative, but not entirely uninformed discussion. I suppose you might not be permitted to advocate another forum within this one. I will search. Thank you again for your time and for your thoughtful and...

Okay. I'm fully aware of the relationship between mass and energy, and the incompatibility of relativity with quantum mechanics. I'm comfortable with non-euclidean geometry, and I'm also aware that a singularity, like an infinity, is a mathematical way of saying "you're asking the question...

I do want to add one more question. If this type of geometry is possible, is there a mechanism for describing this type of closed space existing within our universe, be our universe flat or closed, or is that a mathematical absurdity?

I'm actually fairly comfortable with this interpretation, I think. So, if I understand this correctly, the idea that the universe used to be smaller than it is now, or that it is getting bigger, is incorrect? It has always been infinite, just more dense? Now it is getting less dense, but is...

Just to clarify, the reason I inferred that the universe is closed is that, while infinite and edgeless, with its center everywhere, it is expanding, and was once much smaller than it is now. So I'm also puzzled by this. During the first handful of Planck times, just after the big bang, if...

I guess what I find puzzling is how spacetime can be flat and infinite, with its center everywhere, but not be "round," or perhaps a better term would be "closed." I always interpreted that, while not actually spherical, the nature of our universe was such that traveling far enough in a straight...

So expansion only exists in empty space, between galaxies and clusters? Why would this be?