New Teacher Seeks Help on Universe Expansion & Space

[narrator]

Adding to Philip's question,

Is the expression "space-time" a bit of a misnomer? It brings with it a sense that space has some quality that acts upon matter. In discussions about expansion, the distinction between space and relative distance between bodies is always pointed out because space in and of itself has no quality that can act on matter. I'm not trying to be glib, but I'm guessing that perhaps because language is less precise than math, that expressions like space-time are more for the convenience of language than precision.

 

[chaszz]

Matter, when in motion, acts on time. The faster some object goes relative to me, the slower its time elapses compared to my time. Protons fired near the speed of light in accelerators become more massive, heavier and harder to accelerate faster as they get closer to the speed of light. They are also flattened perpendicular to the direction of flight, so they become vertical ellipses, because their space is shortened in that direction. Particles called muons which have a known rate of decay, when fired in accelerators, take longer (in our time) to decay because their time slows down as they approach the speed of light. A large gravitational mass like the Earth bends the space around it, and also slows down time near it. These are some of the interdependent relativistic relationships of space, mass and time. They are why "spacetime" is more than a convenient way of expressing something about two unrelated entities. These relationships have been proven to exist many times in experiments of many different types. Before making generalizations about what space is and its relationship to time, I suggest you guys might want to read the stickies and the FAQ in the Relativity forum. I am a layman myself and know that it can be cutting to be spoken to this way, and I am sorry about it. But these forums are supposed to be places dealing with verified physical conclusions, not opinions.

 

[narrator]

Before making generalizations about what space is

Mine is a "generalization" that has been repeated here many times in answer to questions. Space is nothing, has no effect on anything, and being nothing is not affected by anything, is basically the message. As one example, when talking about expansion, the oft repeated clarification is that expansion does not produce more space but more distance between objects, because space (being nothing) cannot be created.

But these forums are supposed to be places dealing with verified physical conclusions, not opinions.

Verified physical conclusion expressed within the bounds of language, which at times can be imprecise.

 

[Tanelorn]

Space and Time are simply dimensions and Spacetime is the apparent warping of these dimensions as a result of the interactions of Bosons and Fermiions.
Space and Time are therefore not like ponderable matter, Space and Time are simply the total range of all possible locations.
According to the standard model of particle Physics all large scale, macro, physical phenomena, ultimately must be derived from the behaviour, characteristics and interactions of Bosons and Fermions.
The standard model of particle Physics is the fundermental heart of all of Physics which is itself the root from which all of science is derived.


I feel like a preacher of religion, but I really do mean this in a rhetorical tone. Also these views are still relatively young and so are still being tested.

 

[petm1]

Space is the area that matter occupies, we measure it by the yard and the second. Relative space-time we measure using a photon, our yard stick, and a clock, us.

 

[juanrga]

I'm brand-new to this site, an English teacher, certainly not a physicist, but I'd sure appreciate some (gentle) help.

The short version of my question:

How can the universe expand into infinite space?

Are there two kinds of space? The first is the distances between galaxies in our universe, and the second, space, is something else?

Where did space come from? Was it there before the Big Bang?

If there is space and space, why isn't there time and time?

Universe is not expanding into infinite space.

There only a kind of space in the equations of the Big bang.

There are different speculations for what there was before the Big Bang, but none scientific hypothesis that can be tested.

 

[chaszz]

Space and Time are simply dimensions and Spacetime is the apparent warping of these dimensions as a result of the interactions of Bosons and Fermiions.
Space and Time are therefore not like ponderable matter, Space and Time are simply the total range of all possible locations.
According to the standard model of particle Physics all large scale, macro, physical phenomena, ultimately must be derived from the behaviour, characteristics and interactions of Bosons and Fermions.
The standard model of particle Physics is the fundermental heart of all of Physics which is itself the root from which all of science is derived.


I feel like a preacher of religion, but I really do mean this in a rhetorical tone. Also these views are still relatively young and so are still being tested.

Relativity does not take its cues from the Standard Model of Particles or from Quantum Mechanics, nor do they take their cues from Relativity. These all may be regarded as fundamental theories though they cannot yet be reconciled with each other. This probably shows that all these theories are not yet fundamental enough and something better is waiting in the wings, for how long nobody knows. The String Theories are candidates, but so far without a shred of proof.

In the meantime, the Standard Model needs the Higgs boson to be found, which may happen in the Large Hadron Collider at CERN. If it is not found, there may be a lot of trouble in the Standard Model. So it is not quite fundamental in any sense as yet. Also many have remarked over the years at the large number of constants in nature that must be "just exactly so" for the Standard Model to work. It may, or may not be, showing cracks in its foundation.

Relativity also may have serious challenges presented to it in (1) The possible exceeding of the speed of light by neutrinos, and (2) quantum entanglement where communication between two particles appears to take place at faster-than-light speeds. So perhaps quantum mechanics, which has no such challenges currently, and is the most successful physical theory of all time, is winning the fundamental wars at this point. But it has little to say on space and time.

Perhaps we may agree to disagree here on the nature of space and time, whether they are real ponderable entities or not, since there are no true authorities to fall back on in "fundamental" theories that disagree with one another and cannot at this time be reconciled. I at any rate am willing to leave it there.

 

[McCartney]

Bosons and Fermions:

Are they floating in space?

If space is expanding. Is there a dilution of Bosons and Fermions?

Is there a vacuum in space?

I would say that if there was a vacuum then space is nothing.

Can space expand into nothing?

 

[Imax]

Think of the Universe as having two possible shapes, infinite or finite. Imagine you’re on Earth and you’re going to travel the Universe in a space ship. You can start off in any direction but you have to travel in a straight line (i.e. a geodesic). If the Universe is infinite, then it doesn’t matter the direction you choose. You can never come back to where you started from. If the Universe is finite (i.e. compact), then you can choose a direction, following a space-like geodesic (i.e. straight line), and you will eventually come back to where you started from. Space doesn’t have to be expanding into nothing.

 

[bill alsept]

Think of the Universe as having two possible shapes, infinite or finite. Imagine you’re on Earth and you’re going to travel the Universe in a space ship. You can start off in any direction but you have to travel in a straight line (i.e. a geodesic). If the Universe is infinite, then it doesn’t matter the direction you choose. You can never come back to where you started from. If the Universe is finite (i.e. compact), then you can choose a direction, following a space-like geodesic (i.e. straight line), and you will eventually come back to where you started from. Space doesn’t have to be expanding into nothing.

If the universe is finite then there is also the possibility that one would come to the edge of the universe. If this were possible then it could also be possible that the density out there would be low and time may be moving so fast out there that we or multiple generations could never live long enough to get there.

 

[Imax]

If the Universe is finite and forms a closed manifold, then it’s compact without boundaries. There doesn’t need to be an edge. The density of Bosons and Fermions can change locally, but their density could be globally homogeneous. If the Universe is finite and compact, then it could take a very, very long time to circumnavigate a closed space-like geodesic. Just because it could be closed does’nt mean that the Universe is small or static. It's possible that we or multiple generations could never live long enough to circumnavigate the Universe.

 

[PatrickPowers]

I'm brand-new to this site, an English teacher, certainly not a physicist, but I'd sure appreciate some (gentle) help.

The short version of my question:

How can the universe expand into infinite space?

Are there two kinds of space? The first is the distances between galaxies in our universe, and the second, space, is something else?

Where did space come from? Was it there before the Big Bang?

If there is space and space, why isn't there time and time?

As far as anyone knows the Universe isn't expanding into anything. We don't know of anything outside of the Universe, more or less by definition.

When the Universe came into existence it was completely crammed with unthinkably dense stuff. Though for some reason it began to expand rapidly, there was no empty space whatsoever for quite some time.

According to Albert Einstein, time and space have no meaning unless there is matter and energy around. Matter and energy create time and space.

I believe that no one at this time has any idea what was there before the big bang.

 

[McCartney]

As far as anyone knows the Universe isn't expanding into anything. We don't know of anything outside of the Universe, more or less by definition.

When the Universe came into existence it was completely crammed with unthinkably dense stuff. Though for some reason it began to expand rapidly, there was no empty space whatsoever for quite some time.

According to Albert Einstein, time and space have no meaning unless there is matter and energy around. Matter and energy create time and space.

I believe that no one at this time has any idea what was there before the big bang.

Einstein and Newton explained gravity; the former with more accuracy. However, I believe we really don't know what is gravity. We have read how mass bends the space, but we don't know how it happens. Sometimes it sounds like a fairy tale because it is hard to imagine such a thing.

Perhaps stars and planets in the universe are the equivalent of protons and electrons within an atom and they are somehow bound together by a force that we are trying to explain.

 

[phinds]

Sometimes it sounds like a fairy tale because it is hard to imagine such a thing.

Depends on your level of imagination.

Perhaps stars and planets in the universe are the equivalent of protons and electrons within an atom and they are somehow bound together by a force that we are trying to explain.

You are right that we don't know WHY gravity does what it does, but the mechanisms of WHAT it does are well understood and your "protons and electrons" analogy sounds like something from a 1930's science fiction story, not something from a science book.

 

[McCartney]

Depends on your level of imagination.




You are right that we don't know WHY gravity does what it does, but the mechanisms of WHAT it does are well understood and your "protons and electrons" analogy sounds like something from a 1930's science fiction story, not something from a science book.

Is more than imagination when one can see the bending of light, however, all we have done is come up with an explanation and the explanation works very well.

LOL, at least it was the 1930s and not 1905. Thanks for your sarcasm.

The issue is we do not yet understand gravity.

 

[PatrickPowers]

Einstein and Newton explained gravity; the former with more accuracy. However, I believe we really don't know what is gravity. We have read how mass bends the space, but we don't know how it happens. Sometimes it sounds like a fairy tale because it is hard to imagine such a thing.

I have read from reliable sources that General Relativity assumes inertia and derives gravity. At seems to be hard to say how this is derived, though.

 

[Tanelorn]

My present understanding is that all macro forces and effects including gravity are as a result of the interactions of Bosons with Fermions and their residuals. The bending of space is simply an illusion because space itself has no objective existence. The same applies to spacetime and time.

 

[McCartney]

My present understanding is that all macro forces and effects including gravity are as a result of the interactions of Bosons with Fermions and their residuals. The bending of space is simply an illusion because space itself has no objective existence. The same applies to spacetime and time.

One needs more than one area in space with mass to have gravity.

Gravity weakens with increased distance among objects. Do bosons and fermions behave differently when they are in close proximity to mass.

Is the boson and fermion network (or concentration) in the universe a constant?

 

[Tanelorn]

McCartney please take a look at this page. It details the Fermions (matter) and Bosons (force carriers). This should help answer your questions.

http://en.wikipedia.org/wiki/Standard_Model

 

[mgervasoni]

They say it's hard to imagine infinite space.. It could be a 4th dimension. BUT, if you did walk all the way to the edge of space and took one more step, you'd be right back where you started. It's like if someone couldn't grasp the concept of a 3 dimensional sphere. You'd put him on Earth and he'd walk and walk and sooner or later he'd get right back where he started, bewildered. Thus may be our ability to conceive how we could get to the edge of space, and be right back where we were.

 

[mgervasoni]

The protons and electrons acting like Solar Systems in the Bohr's atom model is what lead to all that science fiction in the 30's and after: universes within universes. Our modern concept of how atoms are and operate is very different from what you learned in high school science.

 

[phinds]

They say it's hard to imagine infinite space.. It could be a 4th dimension. BUT, if you did walk all the way to the edge of space and took one more step, you'd be right back where you started. It's like if someone couldn't grasp the concept of a 3 dimensional sphere. You'd put him on Earth and he'd walk and walk and sooner or later he'd get right back where he started, bewildered. Thus may be our ability to conceive how we could get to the edge of space, and be right back where we were.

I understand what you are saying but the "edge of space" is a very poor concept and should be avoided, since there isn't one.

 

[Imax]

There’s no need for an edge if the universe is finite or compact. It’s just like on Earth. You can travel in a straight line on Earth and you can come back to where you started from. The difference is that on Earth you’re limited to a 2D surface, but the Universe is 3D.

 

[Bread18]

There’s no need for an edge if the universe is finite or compact. It’s just like on Earth. You can travel in a straight line on Earth and you can come back to where you started from. The difference is that on Earth you’re limited to a 2D surface, but the Universe is 3D.

That would happen if we lived in a closed universe and, as far as I know, there isn't any evidence for that.

 

[mgervasoni]

I understand what you are saying but the "edge of space" is a very poor concept and should be avoided, since there isn't one.

Totally right Phinds, that was my point but perhaps poorly described. Just like there is no edge on earth, so is space/the universe... And again some people did think the Earth was flat/finite at one time which we just shake our heads at now.

And that's a very thought provoking statement that the Earth is 3D with a 2D surface, perhaps the universe is 4D with a 3D "surface"? (That's some string theory and other theories right?) Anyway, no need to speculate but it's a extremely interesting topic, and it's always good for our minds to think. :)

 

[Imax]

That would happen if we lived in a closed universe and, as far as I know, there isn't any evidence for that.

I’m trying to point out that there is no need for an edge, regardless of whether the Universe is finite or infinite. And, I agree with you. There is very little observable data indicating that it’s finite. Some models using Cosmic Microwave Background Radiation suggest that it may be finite, but I don’t think these are very conclusive. But, to quote Wiki (http://en.wikipedia.org/wiki/Big_Bang):

“According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly.”

How can you have rapid expansion in size if the Universe is infinite?

 

[Imax]

And that's a very thought provoking statement that the Earth is 3D with a 2D surface, perhaps the universe is 4D with a 3D "surface

It’s hard to imagine what a 3D Universe would look like embedded in 4D space.

 

[phinds]

.”

How can you have rapid expansion in size if the Universe is infinite?

Math involving infinity is NOT like normal math. If you double infinity what you get is EXACTLY the infinity that you started with.

 

[Drakkith]

How can you have rapid expansion in size if the Universe is infinite?

The SIZE of the universe may or may not have increased. The distance between all objects in the universe did increase as a result of expansion. Is that easier to visualize? With an infinite universe, doubling the distance between all objects is exactly the same as in a finite universe.

 

[Imax]

The SIZE of the universe may or may not have increased. The distance between all objects in the universe did increase as a result of expansion.

The Big Bang theory postulates that the size of the Universe is increasing and it possibly starting from some kind of point singularity. The question is Space. Was Space finite or infinite near the time of the Big Bang event? Did the Universe start out in an infinite space with its entire mass confined in a very small volume, or did the big bang event itself create space?

I can’t help but think that the BB singularity had some properties similar to Black Holes, and Black Holes can bend space-time. It’s possible that space was compact near the Big Bang, with all the mass/energy of the Universe confined to a point singularity.

 

[Drakkith]

The Big Bang theory postulates that the size of the Universe is increasing and it possibly starting from some kind of point singularity. The question is Space. Was Space finite or infinite near the time of the Big Bang event? Did the Universe start out in an infinite space with its entire mass confined in a very small volume, or did the big bang event itself create space?

To my knowledge the universe contains everything, including spacetime. Whether the size of the universe if finite or infinite is unknown.

I can’t help but think that the BB singularity had some properties similar to Black Holes, and Black Holes can bend space-time. It’s possible that space was compact near the Big Bang, with all the mass/energy of the Universe confined to a point singularity.

The Earth bends spacetime. So does my Dr. Pepper can sitting here on the desk next to me. A black hole only bends spacetime stronger than either of the former do. Also, as I have seen here on PF, supposedly most cosmologists don't believe an actual physical singularity existed, but that it is simply a consequence of having an incomplete theory.

 

[phinds]

The Big Bang theory postulates that the size of the Universe is increasing and it possibly starting from some kind of point singularity.

Absolutely not correct. There was NO "point" at which the BB happened, it happened everywhere. If there had been a point, the U would not exhibit the isotopy and homogeneity that are now observed.

 

[petm1]

I understand what you are saying but the "edge of space" is a very poor concept and should be avoided, since there isn't one.

Take a picture of any amount of time your camera will let you. We can make the illusion of photons going the opposite direction in time by making a negative. In this negative view the objects appear as holes and space the source of photons. Both pictures are of edges in my universe the edge is between inner space-time and outer space-time. Hope this helps.

 

[Tanelorn]

Chalnoth, what are you thoughts on the following?

"If you were traveling at the speed of light and turned a flashlight on, what would happen to the light?
Relative to you, the light from your flashlight would still be moving at 3 x 10^8 m/s.
To allow this to happen, your perception of time slows down the faster you move and you gain more mass (E=mc^2)."


I believe the above is correct. So my question is, at the beginning of the BB when all particles were moving very fast, would time effects like the above example effect our estimates for the rate of inflation, or even our estimates for the age of the universe since particles were moving very fast for quite a while? I am very uncertain of which relativitic frames of reference apply in this case.


Thanks!

 

[phinds]

Take a picture of any amount of time your camera will let you. We can make the illusion of photons going the opposite direction in time by making a negative. In this negative view the objects appear as holes and space the source of photons. Both pictures are of edges in my universe the edge is between inner space-time and outer space-time. Hope this helps.

I do not wish to be rude, but this is just nonsense and has nothing to do with physics.