Jump to content
Edisonian

Where Does Space End? It Must End Somewhere!

Recommended Posts

I refer the right honourable gentlemen to a post i made further up.I do not mind your sarcasm but its not that difficult to get Ste to email you i could give you a ref if you wish

Share this post


Link to post
Share on other sites

isn't a coid a region of SPACE that has no matter in it? if so, it would still be part of this universe.

Share this post


Link to post
Share on other sites
I refer the right honourable gentlemen to a post i made further up.I do not mind your sarcasm but its not that difficult to get Ste to email you i could give you a ref if you wish

 

It wasnt sarcasm, no pun intended there. I was just saying, hey everyone knows someone, or at least knows someone that knows someone. So, how do you define void.

Share this post


Link to post
Share on other sites
isn't a coid a region of SPACE that has no matter in it? if so, it would still be part of this universe.

 

If you entered into it, then it would have matter, then there would no longer be that void, and space just expanded.

Share this post


Link to post
Share on other sites

putting matter in space does not make it expand. it makes it contract.

 

there have to be space to put the matter to expand said space, so it makes no sense.

 

the "void" would contain space which would mean it is part of the universe.

Share this post


Link to post
Share on other sites

The term "void" generally means nothingness, rather than an empty instance of x.

 

 

putting matter in space does not make it expand. it makes it contract.

No, he means all the space that exists just got bigger, as in expanding territories.

Share this post


Link to post
Share on other sites
The term "void" generally means nothingness' date=' rather than an empty instance of x.

 

 

 

No, he means all the space that exists just got bigger, as in expanding territories.[/quote']

 

Like if you draw a line, and you are standing to the left of it, and to the right of the line you have the void. If you step over the line and draw a new line, the void just got moved farther out, and space just expanded.

Share this post


Link to post
Share on other sites

The void isnt enveloping the universe like a nice jacket,its devoid of all matter,immeasurable.Its a barrier it doesnt exist as a thick empty part of space.By its very definition it doesnt exist.Try looking at it from a different perspective the universe continually turning in on itself with nothing further to expand into.

Share this post


Link to post
Share on other sites

Or say hyperthetically you set off in your space ship in a given direction eventually you would return back to your start point.Maybe thats why time and space are curved.

Share this post


Link to post
Share on other sites

I said that earlier....

 

Think of it as a continues loop, or if you are standing in front of door looking in a dark room, with the exact same door behind you. You then throw a ball into the door in front of you, and it hits you in back of the head.

 

Or if lets say you have a piece of paper, and you draw a circle on it representing Earth, you then bend the paper to make the ends touch and create a cylinder. You draw a line from the circle and you end back at the circle. Is that what you mean philbo?

Share this post


Link to post
Share on other sites

yes i do if you accept the barrier( its difficult to fingd the correct words)but this would in my opinion make the universe finite without saying whats outside of that,and that etc.

Share this post


Link to post
Share on other sites

Space is infinite, and cannot be empty, as the uncertainty principle applying to particles and so-forth applies to fields (gravitational and electromagnetic, etc.) aswell. In the words of Stephen Hawking "in empty space the field cannot be fixed at zero, because then it would have both a precise value of zero, and a precise rate of change (also zero). There must be a certain minimum amount of uncertainty, or quantum fluctuations, in the value of the field. One can think of these fluctuations as pairs of virtual particles of light or gravity that appear together at some time, move apart, and then come together again and annihilate each other."

It is also predicted that there will be pairs of virtual matter particles also, one matter and one anti-matter that would also continually be annihilated.

Therefore the only way space can have any sort of boundary would be if it (space-time) was indeed curved in on itself, but would not be an edge because beyond it would be a complete void. It should be noted that this is nothing like space, or 'empty space' as we define it, and irrelevant to our universe.

Share this post


Link to post
Share on other sites

Therefore the only way space can have any sort of boundary would be if it (space-time) was indeed curved in on itself' date=' but would not be an edge because beyond it would be a complete void. It should be noted that this is nothing like space, or 'empty space' as we define it, and irrelevant to our universe.[/quote']

Yes ive tried to put across to all this complete void, not 'empty space' and to me it is relevent as it makes the universe finite,and open to us a treasure of wonders far greater than we could imagine( was that a bit over the top dramatics)

Share this post


Link to post
Share on other sites

The universe cannot be infinite(the law of conservation of energy)to expand further than its maximum it would require an energy source' date='Seeing how it is accepted that some form of bigbang started the expansion,when all the energy is converted the end yes(like your car using its petrol tank up).

Now what is outside the universe is the void,which is empty of all matter,nothing exists there,no time to measure its thickness because no matter is present nor ever will be...[/quote']

 

Sorry, but I disagree with this. Space is infinite, in the sense that most people mean: if you set out in one direction you can travel forever without ever hitting a boundary. There is no 'void' - space just keeps on and on. I don't see why you have a probelm with the conservation of energy here, and I am a little unsure of what you mean by the universe's 'maximum'?

 

At the moment of the big bang, space-time was 'created', and it was then already infinte (created is not really an adequete word since 'created' really implies time existing before, which it didn't - we have argued this many times with the philosophy nuts who visit here from time to time). All it is doing is stretching outwards. If there was enough mass to close the universe (which there is not), the gravitational attraction of the mass in the universe would eventually overcome the initial impetous of the big bang and the universe would start to collapse. At the 'big crunch', the universe would still be spacially infinite (or have periodic boundary conditions). In actuallity, there is not enough mass to do this (according to the WMAP data) so it will keep expanding forever, and the universe will undergo a heat death.

 

Notice that whether or not space is infinite is not the same as whether or not there is infinite mass in the universe. The latter has been proven to be false, but the former has not. It doesn't really make sense to have a boundary though, since that would imply a 'centre' to the universe, breaking translational symmetry.

 

When we look at the night sky, the universe that astronomers see is finite but in a different sense. Since the light which we see has to take time to get to us, and the universe is about 14 billion years old, the furthest we can possibly see is 14 billion light years (actually it is less than that, but these are details...). So in this sense the universe is finite, but I think that is a little misleading.

Share this post


Link to post
Share on other sites

im not sure whos making the assumptions you are talking about, but:

 

space is infinite, however we say that space has edges... these edges are the furthest bit of matter in a certain direction. beyond that is matterless space - a true vacum. so when a comet or something goes past the 'edge' of space, it creates a new edge.

(i dont know how matterless waves and particles e.g. EM radiation and photons/phonons fit into this though)

 

can you accept that? (re-reading that sounds rude, its meant in a friendly way :D)

 

infinite is not a human, everything human has a limit or boundary, it is a non-human concept 'infinit' (except in maths...) is not possible to imagine, but it is scientificly prooven, we are an advance nation (in a sense) we can proove things like this and know they are true.

and i know your there thinking that they used to think the world was flat... in a few hundred years this will seem like stupid rubbish, however somewhere the stupid rubbish will stop coming out... and that time has already happened, we are advance enough to know stuff like this. (repeat top two paragraphs for a good effect!)

Share this post


Link to post
Share on other sites

5614 apart from reminding me just how confusing my posts must be,you surpass my expectations just what the heck are you talking about.

(quote)im not sure who is making the assumptions you are talking about.....

and i know your thinking that they used to think the world was flat...in a few hundred years this will seem like stupid rubbish,however somewhere the stupid rubbish will stop coming out...and that time has already happened,we are advance enough to know stuff like that(end quote)

Now i take it for granted regardless of the field of ones expertise,most here have an average intelligence(though my spelling at times is fun lol)

so when i pass the buck and ask others to point out someones presumptions(pssst there not based on fact mate...)

I did not expect someone to not (a)understand the question (b) make a conceited remark like we are advanced enough to know stuff like this.( mmm were does the we fit into that...you dont include yourself in that statement do you)

Share this post


Link to post
Share on other sites

Well, lets take it one step at a time shall we philbo?

 

1. To which post were you refering (presumptions)? (They are numbered.) Post 40?

 

2. Which 'presumptions' do you see and object to?

Share this post


Link to post
Share on other sites

I think the presumptions they were referring to were (post 40)

 

1. you assume our universe to extend equally in all directions to infinity

2. space time to extend outwards in all directions along straight lines to infinity

3. that this entire fabric of space-time was created at the very instant of the big-bang

 

and I'm not even going to try with post 42... space having an 'edge' that is the furthest bit of matter in our universe? this seems to me an extremely simplistic and naive view of things (uncertainty principle anyone?!?).

 

oh and before anyone points to my previous thread, i do in fact agree with them (post 40), I'm just not so sure that our universe is not curved in on itself making it thus finite (but there would still be no realistic boundary).

Share this post


Link to post
Share on other sites

I'm just not so sure that our universe is not curved in on itself making it thus finite (but there would still be no realistic boundary).

 

If you believe the experimental data' date=' then it's not. WMAP has shown that the universe is open - not closed.

Share this post


Link to post
Share on other sites

personally, i think WMAP was a waste of money. it is based on a small part of our universe.

Share this post


Link to post
Share on other sites
personally, i think WMAP was a waste of money. it is based on a small part of our universe.
Could you expand on that please, if you have rough figures to hand? How much money? How small? Thanks.

Share this post


Link to post
Share on other sites

The way I see things...

 

The universe is now aged at 13.7 billion years isn't it now??

But the universe is too big to have grown this much in that time, then they introduced this "inflation stage" of development and everything fitted into place again. Back then it could expand quicker than it does now.

 

What's outside the universe?? I LOVE this one!!

You can't say there is a void or just nothing outside our universe. Because even nothing not even a void could exist outside it.

So to be accurate you've got to say, there's nothing at all not even nothing outside out universe, haven't you??

 

 

What if there was a galaxy right on the edge of the universe??

I think if I was on a planet in that galaxy I'd be packing my bags and legging it as far away as possible. So maybe we'll find out about the edge of the universe when the fleet of alien ships come whizzing by, stopping to tell us we're going the wrong way. ;)

 

 

Another theory I have is that any particles trying to become a part of this nothing that's not even nothing, will be repelled with more force than it went in with.

But I mentioned that in another thread about tachyons. ;)

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.