physical space?

[losfomot]

Physical space is abstract and depends on the absolute. If one removes the absolute' date=' then there is no physical space.

 

Gottfried Leibniz (Sir Isaac's nemesis) rejected the physical existence of space, absolute or otherwise. I believe he was correct. Only the absolute is physical (matter and energy), the relative is abstract (only in our head).[/quote']

 

Doesn't relativity imply the physical existence of space?

 

When people talk about space being flat or curved, or when people talk about space having geodesics... doesn't this imply the physical existence of space?

 

And yet relativity, by definition, also states that everything is relative, there are no absolutes.

[J.C.MacSwell]

Doesn't relativity imply the physical existence of space?

 

When people talk about space being flat or curved' date=' or when people talk about space having geodesics... doesn't this imply the physical existence of space?

 

And yet relativity, by definition, also states that everything is relative, there are no absolutes.[/quote']

 

 

My personal view is yes, but with no preffered frame/s in which matter could be considered at rest.

[Tom Mattson]

Doesn't relativity imply the physical existence of space?

 

SR is certainly consistent with this view' date=' but GR lends a lot more support to Leibniz, who I happen to agree with. Leibniz held to what is now called the relational view of space and time. That is, if there were no objects and no events, we would have no concept of space or time. It holds that if the universe were devoid of matter, energy, and dynamical processes that there would not be this huge empty container with a ticking clock left over. There would be literally [i']nothing[/i].

 

When people talk about space being flat or curved, or when people talk about space having geodesics... doesn't this imply the physical existence of space?

 

Not really. It's just a convenient mental picture.

 

And yet relativity, by definition, also states that everything is relative, there are no absolutes.

 

Relativity does not say that, nor does it imply it. There are invariants in relativity, which are known as Lorentz scalars.

[Severian]

One should think of space-time as simply a rule which allows you to define a distance between two events. Whether or not you choose to regard that as something physical, existing separately from the events themselves, is up to you but is once again an unscientific question since it is untestable.

[Dave]

Okay, this thread is now re-open. The other posts have been junked - try and get it right this time, guys.

[Deviation]

Kind of like the Big Bang?

 

If the space was created in the bigbang then why can we consider that point as the 0,0,0 cordinate for the universe ?

[swansont]

If the space was created in the bigbang then why can we consider that point as the 0,0,0 cordinate for the universe ?

 

There's no way of telling where that point is.

[Johnny5]

If the space was created in the bigbang then why can we consider that point as the 0,0,0 cordinate for the universe ?

 

 

There's no way of telling where that point is.

 

 

How about look towards polaris?

 

Yes no?

[Deviation]

There's no way of telling where that point is.

 

May be not but then its certainly at the center of universe.

 

There may be a way to find it.

 

All things have speed of time relative to each other. ie. Faster the object slower its time and viceversa. So if we can find objects that have the fastest time relative to all the objects in the universe then thoes objects must be very near to the Origin point of the universe.

 

Thanks.

[Saint]

Doesn't relativity imply the physical existence of space?

 

When people talk about space being flat or curved' date=' or when people talk about space having geodesics... doesn't this imply the physical existence of space?

 

And yet relativity, by definition, also states that everything is relative, there are no absolutes.[/quote']

 

I think your question has two parts. First, relativity would like to see light as travelling through nothing. That is, light requires no medium If it did, then relativity would have issues. So in that sense, relativity would like to see "empty" space. But I guess it could also require that light simply not interact with physical space, if it exists.

 

Second, I think you are correct about your take on gravity (bending space, blah blah blah). People here have stated that that is simply a mental construct to help us better understand reality (ie. we need to view space as physical, so we use that model).

 

Gravity has been explained in a number of ways. Some have said that mass alters space itself. Some have said that mass generates gravity particles. Or any combination of the two. If mass alters space itself, then there must be something to alter - physical space. If mass generates particles (waves), then there must be something through which those particles (waves) move. If there is no medium, then there are no waves.

 

Hey, at least the absence of physical space could solve the duality of light problem.

[losfomot]

Okay, this thread is now re-open. The other posts have been junked - try and get it right this time, guys.

 

 

I thought that this was a good idea at first, I like the idea that threads be kept 'on track'... but too much was junked... better to have a thread that gets off track than to have a thread that is amputated. Oh well, now I know.

Funny how this one got off track right away again.

[losfomot]

In our universe, we look in one direction, and we can see galaxies roughly 13-14 billion light years distant. We can't see further than that because things are moving away from us at close to the speed of light, and are redshifted out of existence (so to speak). We see the same thing in the opposite direction. If we were to pick a galaxy from each direction, each at a distance of 13 billion LY (we'll call them galaxy A and B), we would be looking at 2 galaxies that are moving away from eachother faster than light. Nothing can move faster than light, so how is this possible?

 

This has been explained by the fact that the motion of these galaxies, relative to eachother, is due to space 'expanding', and therefore is not subject to the speed limit of C.

 

However.. 'fact' seems like a strong word here. If space is not a physical entity to expand, then it seems like this explanation breaks down. If 'space' is not really expanding, then galaxies are simply moving away from eachother faster than light (thereby (assumedly) increasing the area of the universe (maybe volume would be a better word?)).

 

So we are still left with the question... How can these objects be moving apart faster than the speed of light?

[Guest Andromeda]

In our universe, we look in one direction, and we can see galaxies roughly 13-14 billion light years distant. We can't see further than that because things are moving away from us at close to the speed of light, and are redshifted out of existence (so to speak).

 

Sorry--but for my understanding...why is that? Are there no other proposed theories to say why we cannot see beyond that certain distance due to redhift and that the other galaxies have to be travelling faster than light(supposedly)?

 

Also--about the fact whether space-time is physically existent--My understanding goes as far as the fact that when we extend our vision into space, we do not see endless amount of galaxies and stars etc. We see darkness which is implying that there is a certain 'edge' to it all. The darkness we see is beyond that of space and space is supposedly expanding into the 'nothingness' outside space. Therfore, space should have physical existence.

 

Do correct me if i'm COMPLETELY missing the point.

[losfomot]

understanding goes as far as the fact that when we extend our vision into space, we do not see endless amount of galaxies and stars etc.

 

Yes we do see endless (well... not endless) amounts of galaxies when we extend our view deep into space. A patch of space which, through an average telescope, shows mostly blackness is actually rich in galaxies. The deepest we've ever looked, I believe, is called the Hubble Ultra Deep Field. You can check it out here.

[losfomot]

In our universe, we look in one direction, and we can see galaxies roughly 13-14 billion light years distant. We can't see further than that because things are moving away from us at close to the speed of light, and are redshifted out of existence (so to speak).

 

It seems that I am wrong about this... most of the galaxies that we see are receding from us faster than light already. See... that's just weird.

[Saint]

It seems that I am wrong about this... most of the galaxies that we see are receding from us faster than light already. See... that's just weird.

 

Well, they are redshifted to the degree that would suggest FTL speeds. There's a difference.

 

Basically, we need to start accepting that physical objects can reach FLT speeds, or find alternate explanantions for the extreme redshift.

 

Up to this point, most relativists have had to stick to the idea that space itself is expanding. Although I don't know how they can claim that "nothingness" is expanding. Where is the extra "nothing" coming from?