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Expansion Into Nothing

by georgiagrace
Tags: expansion
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georgiagrace
#1
Sep18-13, 11:45 PM
P: 4
Hello. I am very curious about astronomy, and nothingness. I have a question though: Many people say the the universe is expanding, and say that beyond the universe, there is "nothing". What I think though, is that "something must exist beyond all that is already here, and this something I think is empty space. But how, could this "nothing", that everything is expanding into, be space that is already there? I guess what I am trying to say is that "nothing", must be "something", that "nothing" does not exist, anywhere. My question is, why are your guys thoughts on this? Thankyou - Georgia
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Hyo X
#2
Sep19-13, 01:20 AM
P: 37
You are right in that 'nothing does not exist, anywhere'. Because if nothing did exist, it would be something.

However, the idea that the universe is expanding is difficult to understand from our daily perspective, in which everything exists, moves, and changes within the three dimensions of space. We try to interpret things with conservation of volume in mind, but that is problematic when dealing with the boundaries of existence.

Perhaps the best way to approach it is to understand how astronomers and scientists have made the measurements that allow us to say that the universe is expanding. By understanding those measurements and how they fit the theory, you can understand the limitations of what we can say with certainty, and you can choose how literally you interpret the predictions and the significance you ascribe to them.
Good luck! Science is fun.
Drakkith
#3
Sep19-13, 01:21 AM
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Our prevailing model does not require that anything be outside the universe for it to expand into. If the universe happens to be infinite in size this doesn't even make much sense unless you start adding dimensions. Keep in mind that while we don't KNOW the universe isn't expanding into something, we DO know that it doesn't HAVE to have pre-existing space to expand into. The distances between all objects within the universe can simply increase over time.

One thing to ask yourself is, what does it mean for the universe to expand? Are there some sort of boundaries?

To our knowledge there is not. The expansion that is described by cosmology talks about objects WITHIN our universe getting further away from each other. It does NOT talk about any boundaries of space moving about. And if there are no boundaries, does it even make sense to talk about the universe expanding into something? If far away galaxies were moving into pre-existing space, well obviously that space is within our universe.

Also, do you understand what expansion actually means in this context? We see galaxies moving away from us, so does that mean we are sitting still while everything moves away? In fact, this is both a yes and a no. An alien in another galaxy, billions of light-years away, sees the entire universe as expanding away from him! So were are all moving away from everyone and everything else, all at the same time.

Does that make sense?

Drakkith
#4
Sep19-13, 01:23 AM
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Expansion Into Nothing

Quote Quote by Hyo X View Post
You are right in that 'nothing does not exist, anywhere'. Because if nothing did exist, it would be something.
I would be very careful about statements such as this.
Without defining and agreeing on exactly what you mean by "nothing", "something", and "exist", people will just get into a huge argument over nothing.
georgiagrace
#5
Sep19-13, 01:51 AM
P: 4
Thanks all for your feedback, it has certainly made me think more. And if you guys are interested in thoughts like these, my friend Alonzo.nieves had similar thoughts, and also a theory, so I would recommended checking that out. Thanks again!
Drakkith
#6
Sep19-13, 02:05 AM
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Quote Quote by georgiagrace View Post
Thanks all for your feedback, it has certainly made me think more. And if you guys are interested in thoughts like these, my friend Alonzo.nieves had similar thoughts, and also a theory, so I would recommended checking that out. Thanks again!
Please keep in mind that a scientific theory is a very different thing from what most people believe it is. While I applaud your friend's interest in science, it is very unlikely that he has a working scientific theory. I say this not to discourage you or your friend, but to educate you and make sure you understand what science is and what it isn't.

http://en.wikipedia.org/wiki/Scientific_theory
georgiagrace
#7
Sep19-13, 02:10 AM
P: 4
Yes, that is true- I see now the difference between an hypothesis and a theory. Thankyou for that!
Dmitry67
#8
Sep19-13, 03:31 AM
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Topic starter, this question is asked every week, check Cosmology FAQ
georgiagrace
#9
Sep19-13, 03:35 AM
P: 4
Ok, thankyou for that recommendation, I am very new to this so I don't quite know where else to get opinions from, so thanks for that!


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