Is space limited?
If so how is space expanding?
So there must be a space outside of space?
What is there?
Is it just an infinite white nothing being engulfed by space every single second?
The way I understand it is that due to the speed of light (among other things), we can only see a certain portion of the universe. For example, the light we can presently see is approximately 13-16 billion years old, and we subsequently use this number as the age of the (visible) universe - the light from ‘our’ Big Bang - but this does not rule out the possibility there is in fact light (i.e. matter) much older than this having simply not enough time to reach our telescopes, light from ‘another’ Big Bang. In other words, the universe’s visible matter may indeed be only a part of what composes the universe (and is, if we include things such as dark matter) but we’re situated in a moment in time where that data (the data that would confirm more visible matter than presently viewable) is simply unavailable. But - we may also not overlook that to assume the universe reaches further than we can now detect would also be mere speculation.
As for the question of how we know space is expanding, it has to do with cosmological redshift. Google it up; I’m sure you’ll find some good stuff.
The Sceptical position comes into mind at this stage, how can we be sure that this one millionth of reality that we Supposedly perceive has any connection to the one millionth of reality that actually exists?
Sisyphus0
That’s such a good question!
Your question might resemble, what does space expand across? Is there a fixed space that we can use to tell whether or not 3-space is expanding? I can’t wait until I take these courses in school. Philosophy and science are addictive.
I wonder though, how should one define space? Should we use the dictionary definition?
We may be stumped on this but I haven’t studied enough to know for sure.
I just wanted to say, “good question.”
Isn’t Space just empty? And don’t atoms just fill space up? So Space is just the thing that gets filled up and so it isn’t really a thing in it-self that can be measured but rather just like pure nothingness.
Sisyphus0
That’s the question isn’t it? I don’t know if that is what space is. If space is nothingness, then shouldn’t we say “space isn’t” rather than “space is”? But if we agree that there is something there that we cannot put our finger on then space is.
Seriously though, I wonder if this is a real problem for scientists. I want to ask aporia this. Aporia has a B.Sc. in Physics and Math and may know more about this than us. It seems to me that maybe space is not non-existent if it expands, but that remark could be just due to ignorance on my own part concerning this subject.
BTW, saying space is something, therefore space is nothing doesn’t make any sense.
When physicists talk about ‘space’ they’re not talking about ‘pure nothingness’, trust me. Space is not a void, and it most certainly can be measured, as well as bent and curved. What is commonly thought of as ‘empty space’ has been proved ‘not empty’ all the way down to the Planck scale (see quantum foam theory).
One way of looking at things is to imagine the concept of ‘north’. At the equator, ‘north’ exists. Move ‘north’. Then continue. You’ll eventually reach the North Pole.
What is north of the North Pole?
Nothing; the question does not make sense. Agree?
Same with space. Space expands. There is nothing beyond space.
north of the north pole is the other side of the world. if you imagine that the 3d universe is analogous to a 2d plane like the surface of a sphere, it curves around on itself and if you go in a straight line for 30billion years, youll end up right back where you started.
if that was true, how would we be able to know that a distant galaxy (or 50 of tehm) isnt actually the milky way a few billion years ago?
the only way i can imagine the universe is as a static space that curves around itself where all of the particles are shrinking
its easy to visualize and avoids this strange problem youve found. therefore it is obviously true. oh you disagree huh? well thats because youre stupid. and now bump the thread i linked to and give me your totally wrong theory.
I’m surprised that no one argued Kant into the discussion. According to him, space and time are those intuitions that pure mathematics bases itself upon when attempting to construct its apodictic and necessary judgements. Mental space is what makes the physical space possible. Space is not a property of the things in themselves, but only a form of our capacity of representation.
Furthermore… oh, no, I’m turning to pedantery. I’ll leave it here, then.