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Right, I'm pretty sure this is exactly correctGood, I don't have to imagine fractal spacetime then!
Speaking of fractals, can a real-world object be a true fractal? Since physical objects have finite sizes, I would think that a fractal is always just an approximation.
Though, that's the same reasoning that says we can't have a perfect circle, so I'm not sure it's as profound as it seemed at first glance
Spooky!Maybe there really is a fundamental particle far below quarks and gluons, which has a really real shape - but it's a 3D Koch snowflake, which (somehow) gives rise to the quantum effects we see at the nano scale, and in turn the classical effects at the macro scale. So who knows, maybe it really is squiggly edges all the way down...
Well, the fact that our universe does not change, on average, as far as we can see strongly suggests that there is more of the same, at least for some significant distance. Exactly how far, we don't know.
It's not expanding from a single point. It's expanding at every point. Everywhere in the universe, the average distance between galaxies is increasing. Objects are moving away from every point. There is no center.If the universe is expanding outward from a single point, why isn't there a vast empty void in the center?
It's not expanding from a single point. It's expanding at every point. Everywhere in the universe, the average distance between galaxies is increasing. Objects are moving away from every point. There is no center.
The singularity is a misnomer. It didn't happen. It can't have happened because it's nonsensical. The existence of that singularity in our equations means that our equations aren't correct that far back in time.Please expand on this - I'm not following. It's my understanding that the universe arose from a singularity that began expanding outward about 13.7 billion years ago. Why then isn't the material universe like the skin of a balloon? I'm probably not explaining myself well here. I appreciate your patience.
Nope. Energy isn't conserved in an expanding universe. If you want a detailed description of the issue, check this out:Wait, it doesn't?
A long, long time. Wikipedia has a good breakdown:How long will it be until the heat death of the universe?
Somewhat. If you read the above link, one of the critical points will be planets being flung from their orbits over time. A sufficiently advanced civilization might be able to prevent this (though it would be one hell of an undertaking).Assuming the human race survives for the lifespan of the universe, can we theoretically delay the heat death of at least a portion of it to preserve our own existence somewhat longer?
The universe somehow gets weirder every time I talk to a physicist!Nope. Energy isn't conserved in an expanding universe. If you want a detailed description of the issue, check this out:
Is Energy Conserved in General Relativity?
The super short version is simply that there is no unique way to define overall energy in General Relativity. And what you can't define, you can't conserve.
But even more simply, an object in motion stays in motion unless acted upon by an external force. In other words, once the expansion gets started, it continues going on its own. There is no need to input additional energy to keep the expansion going.
Well, you can, as long as both vectors are at the same point. That is, you can find the relative velocity between two objects only as they are passing one another. Once the objects are far away, you can no longer simply subtract their velocities: the curvature of space-time in between the objects makes the definition of vector subtraction ambiguous.Hmm. Wait, why can't you simply add vectors in curved spacetimes?
Well, no, it doesn't work that way. From our perspective, we will always be (nearly) stationary with respect to the expansion. So will every other galaxy, from their perspective.I heard in passing something about the expansion of the universe observed to be accelerating. If this is the case, will we reach relativistic velocities in the future that will effectively cease the passage of time from our perspective?
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