Is the edge of our universe within our reach?

I believe that the edge of our universe is within our reach because the only way that i see disproves this is for inflation to be faster than light. As this might cause trouble with time, I think that that's the only explanation. If you assume that there's a center, than the edge must be within reach of the center. As we are obviously not at the center, we must be close to an edge.

DaveC426913
Gold Member
If you assume that there's a center...
Don't.

The universe has no center and no edge.

Or more appropriately, everywhere is the centre.

The observable universe has an adge but it will always be too far to reach, since, like a flashlight you are pointing at your feet, we will always be at the centre of what we can see.

We can't reach the edge of the universe because it's expanding at the speed of light, and as we know nothing can go as fast as the speed of light. I guess in a way, the universe is infinite relative to us.

Don't.

The universe has no center and no edge.

Why? Big bang happened at single point, and expansion is from that point. Expansion is always from somewhere to somewhere. If it happen to be a collapse of the universe than it shall collapse also to a single point, some very single point with some specific coordinates in our so far 3D percieved space.

The answer to the question should be: We don't have the edge of the universe. So far we have an edge of the observable universe. What lies beyond the observable boundary is the burning topic for scientific philosofers.
And yes, the observable universe is so big that its boundaries are in no way reachable for us.

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Yes, but we can't see where the center is, as every point can look like the center equally to us.
So everyone on Earth can rightfully say that they are at the center of their universe! =)

Anyway, the universe isn't so much expanding, it is more of stretching itself. Just imagine bread dough as the universe, with raisins in it as galaxies. As the dough bakes in a zero gravity oven, the raisins don't move, the amount of bread between them increases. And if you have an incredibly huge piece of dough expanding at 70 km/s/parsec (this is the expansion rate of the universe) and you can only see it expanding from inside the dough, you don't know where the center of the bread is.

wouldn't the Big Bang have happened in a single, definable point of space?
since all edges would be equal from the center, wouldn't it be a center?.........

Drakkith
Staff Emeritus
The big bang did not happen in a single point in space. Why? Because there was no space there for it to be in! The big bang was an expansion OF space itself. An expansion OF the universe itself as a whole. Every point in space is expanding away from every other point in space. There is no center, and there is no edge.

Now, a common example is the balloon. Imagie putting a bunch of dots, equally spaced, with a marker on an uninflated baloon. When you blow into it, the balloon expands. Every point on that balloon is moving away from every other point on the balloon. A dot that is 10 dots away from another dot is moving away much faster than one that is only 5 dots from that same dot.

Now, the key here is to realize that while the balloon is expanding INTO space, the expansion OF space itself does NOT require it to be expanding INTO something. I know it doesn't make any sense, but there is good reason that it is described that way.

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The big bang did not happen in a single point in space. Why? Because there was no space there for it to be in! The big bang was an expansion OF space itself. An expansion OF the universe itself as a whole. Every point in space is expanding away from every other point in space. There is no center, and there is no edge.

Now, a common example is the balloon. Imagie putting a bunch of dots, equally spaced, with a marker on an uninflated baloon. When you blow into it, the balloon expands. Every point on that balloon is moving away from every other point on the balloon. A dot that is 10 dots away from another dot is moving away much faster than one that is only 5 dots from that same dot.

Now, the key here is to realize that while the balloon is expanding INTO space, the expansion OF space itself does NOT require it to be expanding INTO something. I know it doesn't make any sense, but there is good reason that it is described that way.

that example with baloon is not explaining your approach - each baloon has its center. Each bubble has its center. Btw there are scientists believing in multiverse in which our universe is just one the the multitude of bubbles. Of course with its centers.

"there was no space there for it to be in" - really? How do you know? LOL.
It is not a scientific truth, it's just a belief which is not shared by all, even among scientists. And besides there are currently even more tries of exotic explanations of a Big Bang (1D-2D-3D-4D), as well as preBang state, cyclic bangs, branes collisions and so on.
Belief is not a truth, its just a belief which may appear as a blunder in the end.

Drakkith
Staff Emeritus
that example with baloon is not explaining your approach - each baloon has its center. Each bubble has its center. Btw there are scientists believing in multiverse in which our universe is just one the the multitude of bubbles. Of course with its centers.

"there was no space there for it to be in" - really? How do you know? LOL.
It is not a scientific truth, it's just a belief which is not shared by all, even among scientists. And besides there are currently even more tries of exotic explanations of a Big Bang (1D-2D-3D-4D), as well as preBang state, cyclic bangs, branes collisions and so on.
Belief is not a truth, its just a belief which may appear as a blunder in the end.

Truth? First of all, NOTHING is 100% true. Every scientific model, theory, or whatever is only true to a certain degree.

"there was no space there for it to be in" - really? How do you know? LOL.

I'm sorry, I didn't realize you came here to laugh at people who gave explanations of current scientific theory.

What I said above is a standard view of the universe. Is it the ONLY view? No!

that example with baloon is not explaining your approach - each baloon has its center. Each bubble has its center.

Which is why it is only an example. Hence my further explanation that the universe was NOT like a balloon and that it is difficult for many people to understand.

If you are simply going to criticize me based on nothing relevant, then please leave.

Is it the ONLY view? No!...
If you are simply going to criticize me based on nothing relevant, then please leave.

You sounded peremptory and it is not acceptable in such a question. Nice that now you had to realise it.
I came here not on your invitation, so let me ignore your silly suggestion.
In turn I would advice you to use "imho" more often when talking about unsolved problems of physics.

Drakkith
Staff Emeritus
You sounded peremptory and it is not acceptable in such a question. Nice that now you had to realise it.
I came here not on your invitation, so let me ignore your silly suggestion.
In turn I would advice you to use "imho" more often when talking about unsolved problems of physics.

Yeah...thats not going to happen and that is a ridiculous thing to expect from anyone. From what has been explained to me and others BY advisors and moderators and such from this site is how I explained it in my post. Like I said, it isn't the only view, but it is the one which, to my knowledge, is the most used by everyone here on the forum. I'm not sure why you are so upset over this.

You sounded peremptory and it is not acceptable in such a question. Nice that now you had to realise it.
I came here not on your invitation, so let me ignore your silly suggestion.
In turn I would advice you to use "imho" more often when talking about unsolved problems of physics.

Just to add to Drakkith above, it's not "imho" - it's the current accepted theory on the matter. Why would anyone claim it's their opinion when they're only going by what is currently accepted in science?

This forum only deals with the mainstream, that is the mainstream.

http://www.physorg.com/news/2011-04-ams-particle-detector-international-space.html: [Broken]

"Never in the history of science have we been so aware of our ignorance," said AMS [Alpha Magnetic Spectrometer] Deputy Spokesperson Roberto Battiston. "Today we know that we do not know anything about what makes up 95% of our Universe."

what "mainstream" we are talking about?

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Drakkith
Staff Emeritus
http://www.physorg.com/news/2011-04-ams-particle-detector-international-space.html: [Broken]

"Never in the history of science have we been so aware of our ignorance," said AMS [Alpha Magnetic Spectrometer] Deputy Spokesperson Roberto Battiston. "Today we know that we do not know anything about what makes up 95% of our Universe."

what "mainstream" we are talking about?

The view that is generally accepted as being the most correct by the majority of science. Which as far as I know, it is.
Just because we know that we don't know everything doesn't mean that everything must be called opinions and such. And it doesn't mean that an emerging theory is any more correct than the current one. That takes evidence and time.

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http://www.physorg.com/news/2011-04-ams-particle-detector-international-space.html: [Broken]

"Never in the history of science have we been so aware of our ignorance," said AMS [Alpha Magnetic Spectrometer] Deputy Spokesperson Roberto Battiston. "Today we know that we do not know anything about what makes up 95% of our Universe."

Yes, and?
what "mainstream" we are talking about?

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Nabeshin
Today we know that we do not know anything about what makes up 95% of our Universe."

This is an incredibly terrible and inaccurate statement. Simply because we do not know what the dark matter particle is or the origin of dark energy does not mean we know nothing about them. In fact, I'd say we've done quite well with dark matter despite not knowing what it is.

Look, if you're just going to criticize mainstream science, then just leave PF right now. There are plenty of other message boards on the internet that will be much more tolerant.

Now if you want to find out why it is that the universe has no centre, then great! There are hundreds of threads here already answering the question, and Drakkith has given a good response already. You've demonstrated a common misunderstanding of some fundamental concepts in big bang cosmology, and that's fine, but you should listen to explanations, not be antagonistic.

Scientific truth is not established by voting of a majority.
The above citation is about the current state of current science ignorance in cosmology and it directly applies to the question discussed in this topic.
Cosmology differs from classic physics where mainstream is really an unshakable mainstream.

Scientific truth is not established by voting of a majority.

Nobody said it was. Do you understand what makes what Drakkith said the mainstream accepted theory?

Nobody said it was. Do you understand what makes what Drakkith said the mainstream accepted theory?

"The view that is generally accepted as being the most correct by the majority of science"

"The view that is generally accepted as being the most correct by the majority of science"

Based on observation/evidence, not a vote. Don't confuse the context.

Drakkith
Staff Emeritus
Scientific truth is not established by voting of a majority.
The above citation is about the current state of current science ignorance in cosmology and it directly applies to the question discussed in this topic.
Cosmology differs from classic physics where mainstream is really an unshakable mainstream.

Scientific truth is established by having theories that best fit the available evidence.

The big bang did not happen in a single point in space. Why? Because there was no space there for it to be in! The big bang was an expansion OF space itself. An expansion OF the universe itself as a whole. Every point in space is expanding away from every other point in space. There is no center, and there is no edge.

Now, a common example is the balloon. Imagie putting a bunch of dots, equally spaced, with a marker on an uninflated baloon. When you blow into it, the balloon expands. Every point on that balloon is moving away from every other point on the balloon. A dot that is 10 dots away from another dot is moving away much faster than one that is only 5 dots from that same dot.

Now, the key here is to realize that while the balloon is expanding INTO space, the expansion OF space itself does NOT require it to be expanding INTO something. I know it doesn't make any sense, but there is good reason that it is described that way.

thanks, i think i understand now

To date, cosmology has not defined an "origin", nor any accepted explanation of, well, anything regarding "creation"
That's just the way it is, for now.