Is the universe truly expanding?

[tressure]

Hello everyone, i am just bothered by the theory that our universe is expanding, if so i want to know, what substance is filling the void as our universe expands, and where does this substance come from,

Thank you

 

[Doug Huffman]

What is "the void" to which you refer, please?

 

[rootone]

Space is expanding, but I don't know of any theory which infers that additional matter is being created as a result.

 

[tressure]

For a thing to grow in size, expand ; something must be added into it... like a balloon. If you want a balloon to expand, u simply blow air into it. Dont you think the same thing should be happening if our universe is expanding?

 

[rootone]

You could expand a balloon by placing it inside a contanier with less air density.

 

[tressure]

What is "the void" to which you refer, please?

okay, you do know that as something expqnd space is created, and has to be filled up by something, when i say void, i refer to this space which has to eventually be replaced by something

 

[tressure]

okay, now you do know that space is vaccume, can you get less pressure/ density than vaccume?.

 

[Doug Huffman]

Cosmological space is mostly a hard vacuum with 10^-6 molecules per cubic centimeter, or, inverting, 10^6 cubic centimeters per molecule.

 

[tressure]

... i just wish you could answer my question, that is, what is getting filled into the space if it is growing

 

[rootone]

Nothing additional has to be filling in the space, whatever atoms it already contains just get more spread out.
Same thing as when you place your balloon in a low pressure container.
You didn't need to put more air into the balloon, but it still got bigger.

 

[tressure]

Okay, i assume you know about multiverse, there should be a boundary, that bounds everything in our universe. If the universe is not expanding and its contants are being spread out, don't you think they would by now have spread outside of the universe?

 

[Doug Huffman]

You are correct that there is a boundary between the universe and the hypothetical multiverse. That boundary is the limit of causation at lightspeed for the age of the universe. Practically, it is how far we can see, the universe's horizon.

 

[rootone]

The multiverse is not known to be a fact, it's a possible explanation for some of the properties our universe has, but the existence of it has never been tested for,
Some think it cannot ever be tested for, and therefore it isn't really a scientific proposition at all.
However the expansion of the universe is a measurable fact.

... Must go now, I have visitors, I'm sure somebody else will like to assist wit your quesiton

 

[tressure]

You are correct that there is a boundary between the universe and the hypothetical multiverse. That boundary is the limit of causation at lightspeed for the age of the universe. Practically, it is how far we can see, the universe's horizon.

ARe you saying that this boundary is not fixed?

 

[tressure]

T

The multiverse is not known to be a fact, it's a possible explanation for some of the properties our universe has, but the existence of it has never been tested for,
Some think it cannot ever be tested for, and therefore it isn't really a scientific proposition at all.
However the expansion of the universe is a measurable fact.

... Must go now, I have visitors, I'm sure somebody else will like to assist wit your quesiton

THanx

 

[tressure]

You are correct that there is a boundary between the universe and the hypothetical multiverse. That boundary is the limit of causation at lightspeed for the age of the universe. Practically, it is how far we can see, the universe's horizon.

I Think it is,logical to say that if really the contants of the universe are moving apart and the universe is not expanding, then a few galaxies would be at that edge or outside

 

[Doug Huffman]

Actually the large structures of the universe, galaxies and clusters and super clusters, are gravitationally bound together. It is the space between them that is expanding.

 

[tressure]

Actually the large structures of the universe, galaxies and clusters and super clusters, are gravitationally bound together. It is the space between them that is expanding.

If that's the case then, what's being injected into space inorder for it to expand, i mean it can't just expand and expand, some substance has to be added into it!

 

[Doug Huffman]

What is space? Was there space before the Big Bang? Will there be space during the hypothetical Big Crunch?

 

[tressure]

What is space? Was there space before the Big Bang? Will there be space during the hypothetical Big Crunch?

Space is vaccum, does this vacuum expand? Where does it come from? if we measure it to be 15 today, and tomorrow it is 20 where did the extra 5 come from?

 

[tressure]

What is space? Was there space before the Big Bang? Will there be space during the hypothetical Big Crunch?

No. Space i a property of big bang, remember reason why space is said to be expanding is due to.the observation that after it banged everything flew apart, but flew apart into what?

 

[Doug Huffman]

No. Vacuum is the absence of stuff. Yes, stuff is roughly constant, already a very low density of stuff per space.

 

[Doug Huffman]

It is NOT an observation! If there is only one singular thing then there doesn't have to be any space. If that singular thing is unchanging then there doesn't have to be any time.

 

[tressure]

No. Vacuum is the absence of stuff. Yes, stuff is roughly constant, already a very low density of stuff per space.

IM going to go to bed now. Thank you so much for helping solve this, i hope we can continue some time... cheers

 

[Doug Huffman]

I commend to you Stanford University's Professor Leonard Susskind's streamed lecture series.
https://www.youtube.com/playlist?list=PLQrxduI9Pds1fm91Dmn8x1lo-O_kpZGk8
He starts with classical mechanics and works through quantum entanglement, I believe the end of the formal series, and extends it with topics of current interest, Explanation of the Higgs Mechanism and The Holographic Principle.

 

[Drakkith]

okay, you do know that as something expqnd space is created, and has to be filled up by something, when i say void, i refer to this space which has to eventually be replaced by something

That is incorrect. The expansion of the universe means that the distance between unbound objects increases over time. It does not mean that space is being filled up by anything. A key thing to note here is that expansion, as explained by General Relativity, is a geometrical effect, not a physical effect. What I mean is that while a balloon has to be filled up with air to expand, a physical effect, the expansion of the universe is a result of the geometry of the universe.

Okay, i assume you know about multiverse, there should be a boundary, that bounds everything in our universe. If the universe is not expanding and its contants are being spread out, don't you think they would by now have spread outside of the universe?

Not really, but it depends on exactly what you mean by 'multiverse'. Galaxies can move outside of our observable universe and never have a chance to interact with us again, so you could almost think of them as existing in a separate universe, but this is simply a result of the accelerating expansion of space. They are still within our actual universe an will remain so forever.

Other types of multiverse theories are different and I couldn't begin to compare all of them.

I Think it is,logical to say that if really the contants of the universe are moving apart and the universe is not expanding, then a few galaxies would be at that edge or outside

The phrases 'contents of the universe are moving apart' and 'universe expanding' mean exactly the same thing. As the distance between unbound objects grows over time, the universe expands. There is no physical barrier that is moving into empty space or into some void or multiverse sea or anything like that. (Not according to the standard model of cosmology at least)

Space is vaccum, does this vacuum expand? Where does it come from? if we measure it to be 15 today, and tomorrow it is 20 where did the extra 5 come from?

What are you measuring? If I were to measure the average density of space it would continue to decrease forever. If I were to measure the average distance between objects, it would increase over time. We can't measure 'the vacuum' because the vacuum is an absence of all matter. We have to measure real objects that exist within this vacuum, such as hydrogen and helium gas.

No. Space i a property of big bang, remember reason why space is said to be expanding is due to.the observation that after it banged everything flew apart, but flew apart into what?

There is no 'big bang'. The big bang was not an event. The big bang theory is a description of the evolution of the universe, starting from its extremely dense, extremely hot state right at the beginning of the standard model and running to the present day, where the universe has expanded and cooled over the course of 13.7 billion years. The common use of 'big bang' refers to an imaginary explosion which is where everything supposedly came from. This understanding is wrong. Nothing in the Big Bang Theory says anything about how our universe was created. It only explains that the universe started off hot and dense and expanded, cooling off over time. It serves as a framework in which to place many other theoretical predictions, such as the calculated abundance of the primordial elements and the evolution of stellar objects, in order to explain our current understanding of the structure and history of the universe as a whole. It does not suggest any ultimate origin for the contents of the universe.

In this it is uniquely similar to the theory of biological evolution. Biological evolution explain how organisms changed over the course of billions of years, growing from extremely simple single-celled organisms into the complex multi-celluar lifeforms we see today. The theory contains many, many other sub-theories that describe, in detail, all the different processes that lifeforms use/undergo. But, like how the Big Bang Theory doesn't explain the ultimate origin of the universe, evolution does not explain the ultimate origin of life. That is a separate theory known as abiogenesis.

 

[diogenesNY]

IM going to go to bed now. Thank you so much for helping solve this, i hope we can continue some time... cheers

Tressure, I suspect that some of this conversation may be only weakly interacting :)

May I suggest that you have a look at the following article:

http://astronomy.case.edu/heather/us211.07/misconceptions.pdf

This is an article by Charles Lineweaver and Tamara Davis, originally published in _Scientific American_ in 2005. It addresses your question (and several others) quite directly. It should provide the enlightenment you are seeking more lucidly than any clumsy attempt that I might make.

diogenesNY

 

[Blackberg]

If you're in space and you pull your hands apart, there doesn't have to be something coming in between. Space is just separation between things. It's nothing but "distance" (Except if you want to talk about photons, cosmic particles, virtual particles etc.)

 

[tressure]

Tressure, I suspect that some of this conversation may be only weakly interacting :)

May I suggest that you have a look at the following article:

http://astronomy.case.edu/heather/us211.07/misconceptions.pdf

This is an article by Charles Lineweaver and Tamara Davis, originally published in _Scientific American_ in 2005. It addresses your question (and several others) quite directly. It should provide the enlightenment you are seeking more lucidly than any clumsy attempt that I might make.

diogenesNY

Thank you i will have a look at it.

 

[tressure]

Ii thought of somethig today ... after all the research i did online ...it makes sense to me that some matter is getting eaten by space, that is why it appears to be growing/ expanding. Then the big question would be: if this is true, which matter is it? Is it ev en possible for a matter to transform into nothing?