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What Is Space?

nautil.us

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Re: What Is Space?

#81

Post by richrichardsson »

chiefofgxbxl wrote: post #66
resu_nimda wrote: post #40

Earlier quoted context omitted.

- The Planck units [0] are generally associated with the attempt to quantize space and time. - Macroscopic phenomena are in turn governed by microscopic phenomena, where the strong and weak forces dominate, so I would say our dimension is equally governed by those. At high energies we know the electromagnetic and weak forces combine into the "electroweak" force, and it is commonly hypothesized that at even higher ene…

From my understanding (just a Quantum Physics I class, I could be wrong here) the Planck units quantize space or time to the extent that they define the smallest thing we can practically measure due to Heisenberg's Uncertainty Principle, but they do not preclude that things can actually be smaller than that. That is, something like length or time can be continuous, but our measurements can only ever be discrete multi…

> For example, a really small object can have a length smaller than the Planck length, but we wouldn't truly know how long it was because the Planck length acts as a fundamental limit on the precision/granularity of our measuring instruments.

Would that be, to all intents and purposes, undetectable by us then? If so then that might be a possible explanation of "dark matter", assuming all these things were individually smaller than the Planck length.

Re: What Is Space?

#82

Post by xioxox »

platz wrote: post #9
Noxchi wrote: post #8

How fast are you really going? One of the things I've thought about is relatively. Consider a toddler strapped to his car seat in a luxurious BMW cocoon while his father speeds down the autobahn at 200km/h. He calmy drinks from his sippy cup. You're in a passenger jet above him going 700km/hr. You're going 500km/hr faster than him. But how fast are you really going? Consider that the Earth is spinning around the sun…

there are no absolute reference frames. only relative ones! however, at least there is a fixed relationship between reference frames they all must obey with regards to the speed of light.

There is the frame of the cosmic microwave background, which allows you to measure you speed with respect to the average expansion of the universe. It's not special in terms of physics, but it is a reference.

Re: What Is Space?

#83

Post by andyjohnson0 »

jsmthrowaway wrote: post #70
sillysaurus3 wrote: post #53

Earlier quoted context omitted.

Could gravity be the result of space trying to deflate/return to the pre-Big Bang singularity, kind of like pulling magnets apart? i.e. is gravity the “opposite” of, or a reaction to, “space?” I may be off the mark with what you believe, but just in case: It's a common misconception that the big bang originated at a specific point. The big bang seems to have happened everywhere simultaneously, so it wouldn't be true…

Holy shit, the Big Bang happened everywhere simultaneously because the Big Bang brought quantum fields into existence. Wow. I get it now. As a non-physicist, wording it like that made a lot that I didn't understand suddenly click.

> the Big Bang happened everywhere simultaneously

Until the big bang happened there wasn't any "where" for anything to happen in

Re: What Is Space?

#84

Post by andyjohnson0 »

resu_nimda wrote: post #40
Razengan wrote: post #16

Some related questions that I don't know where, or how, to ask: - Is there a “quantum” of space? Where/how is location stored? - If electromagnetic repulsion is what makes matter “take space”, and if virtually all macroscopic phenomena are governed by electromagnetism and gravity, then could this reality be said to be “gravelectromagnetic”, and might there be other “dimensions” governed by other forces, like “cones”…

- The Planck units [0] are generally associated with the attempt to quantize space and time. - Macroscopic phenomena are in turn governed by microscopic phenomena, where the strong and weak forces dominate, so I would say our dimension is equally governed by those. At high energies we know the electromagnetic and weak forces combine into the "electroweak" force, and it is commonly hypothesized that at even higher ene…

> the Big Crunch, where gravity would pull the universe back to a single point

Just as the big bang didn't happen in a single place, a Big Crunch wouldn't be a contraction back to a single point. Rather, the scale factor [1] that characterises cosmic expansion would simply(!) decline back to zero.

[1] https://en.wikipedia.org/wiki/Scale_factor_(cosmology)

Re: What Is Space?

#85

Post by [deleted] »

graycat wrote: post #22

Do we know enough yet to have some good guesses about (1) the purpose of the universe, https://news.ycombinator.com/item?id=14570170 (2) the end of the universe, (A) big expansion and cool down to nothing, (B) no more expansion and cool down to nothing, (C) contraction back to another big bang, (D) something else very different?

[deleted]

Re: What Is Space?

#86

Post by jdkuuuu »

jsmthrowaway wrote: post #70
sillysaurus3 wrote: post #53

Earlier quoted context omitted.

Could gravity be the result of space trying to deflate/return to the pre-Big Bang singularity, kind of like pulling magnets apart? i.e. is gravity the “opposite” of, or a reaction to, “space?” I may be off the mark with what you believe, but just in case: It's a common misconception that the big bang originated at a specific point. The big bang seems to have happened everywhere simultaneously, so it wouldn't be true…

Holy shit, the Big Bang happened everywhere simultaneously because the Big Bang brought quantum fields into existence. Wow. I get it now. As a non-physicist, wording it like that made a lot that I didn't understand suddenly click.

This really makes it sound like a simulation

Re: What Is Space?

#87

Post by jdkuuuu »

ChuckMcM wrote: post #49
kobeya wrote: post #48

Earlier quoted context omitted.

> If someone was going to say "Well I don't know anything about that, ask someone else." Then the company knew they weren't going to be as successful as we would want them to be. Except that is EXACTLY the correct response -- "I don't know, but I understand that physicists have a good idea of what space-time is, and I'll review the literature and see what the scientific consensus is and we can work from there." The e…

I completely agree with you. When I said (paraphrased) "I don't know, ask someone else" I meant literally that. People who are asked a question about something they don't know anything about can either, do as you suggest propose a way to research the question (win), or do as I've observed refuse to go any further (lose). People who make things up on the spot generally are weeded out before we got to that point.

Not if the question is “how should we say this in Greek?“ and the guy in the next office knows Greek.

Re: What Is Space?

#88

Post by [deleted] »

ChuckMcM wrote: post #49
kobeya wrote: post #48

Earlier quoted context omitted.

> If someone was going to say "Well I don't know anything about that, ask someone else." Then the company knew they weren't going to be as successful as we would want them to be. Except that is EXACTLY the correct response -- "I don't know, but I understand that physicists have a good idea of what space-time is, and I'll review the literature and see what the scientific consensus is and we can work from there." The e…

I completely agree with you. When I said (paraphrased) "I don't know, ask someone else" I meant literally that. People who are asked a question about something they don't know anything about can either, do as you suggest propose a way to research the question (win), or do as I've observed refuse to go any further (lose). People who make things up on the spot generally are weeded out before we got to that point.

[deleted]

Re: What Is Space?

#89

Post by vidarh »

kobeya wrote: post #57
TheSpiceIsLife wrote: post #52

Earlier quoted context omitted.

You can have it both ways. I'd probably say something like "That's not my field of expertise, though if you'd like me to speculate I'd be glad to."

The point is I don't see how speculation about things you know nothing about is supposed to be an accurate gauge of a persons inate intelligence.

How you speculate about things you know nothing about is a far better gauge of problem solving skills than asking questions about an area where you can rely on learned facts, in my opinion.

It's not going to be accurate, but that is not the point. The point is whether you return a blank stare or start trying to reason and analyse the problem.

Sure, you might end up with any number of "I have no idea what the right value for this is - if it wasn't an interview, I'd look it up, but for the sake of argument let's say the value is X". That's fine. Your ability to make that leap and continue is more important than the right result (so is your ability to recognise and admit that you don't know and are substituting guesses)

Re: What Is Space?

#90

Post by comboy »

Razengan wrote: post #16

Some related questions that I don't know where, or how, to ask: - Is there a “quantum” of space? Where/how is location stored? - If electromagnetic repulsion is what makes matter “take space”, and if virtually all macroscopic phenomena are governed by electromagnetism and gravity, then could this reality be said to be “gravelectromagnetic”, and might there be other “dimensions” governed by other forces, like “cones”…

r/askscience on reddit is my go to place for this kind of questions
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