Is the universe infinite or finite?

[Alexizupinhea]

I believe that's not true, but a don't remember well enough to explain why it's not it at this time.

I'm pretty sure, though not an expert, that light moves at c in a vacuum relative to anything and everything; and thus no object, including light, even if somehow already "attached" to an object moving at some fraction of the speed of light (one that is worth saying).... the light being "emitted" or "thrown" will still only move at the speed of light, c, relative to anything (I want to say the light itself being the only exception, but I don't want to say something wrong).

 

[ninja_tux]

I'm pretty sure, though not an expert, that light moves at c in a vacuum relative to anything and everything; and thus no object, including light, even if somehow already "attached" to an object moving at some fraction of the speed of light (one that is worth saying).... the light being "emitted" or "thrown" will still only move at the speed of light, c, relative to anything (I want to say the light itself being the only exception, but I don't want to say something wrong).

Yes! You are correct, like I said it's explained by Einstein's Theory of Special Relativity. You can read a not-so-jargonny explanation of it here: Special relativity - Simple English Wikipedia, the free encyclopedia or another good explanation here:HowStuffWorks "How Special Relativity Works"

If you don't want to read that, basically what happens is that relative to anything (that is, in any frame of reference) the speed of light in a vacuum will be exactly the same.

As far as I'm aware, light is the only known thing to "warp" the classical rules so to speak haha The only other thing I can think of would be gravity waves...which have been theorized to exist but yet to be detected by man.

 

[Cenobite9]

It is also possible that the universe could be much like going around the Earth in that one would never reach the end, they would just end up back where they started. I believe this was one of the theories that Dr. Michio Kaku guy had about the universe.

 

[nikokapo]

It is also possible that the universe could be much like going around the Earth in that one would never reach the end, they would just end up back where they started. I believe this was one of the theories that Dr. Michio Kaku guy had about the universe.

Huh? So each "planet" would have its own universe? Where would these planets exist then?

 

[zaery]

Actually, the expansion of the universe is accelerating.

You're right, but what i was trying to say is that we cannot see the entire universe, because the light from the farther places hasn't reached earth yet. Therefore, the area that we can see is expanding at exactly the speed of light, and isn't changing.

Also, for everyone else, time dilation messes with people's brains. If it's 100% correct, and has no theoretical flaws, then from a photon's point of view, it is emitted and absorbed at the exact same time >.<

 

[ossumguywill]

I don't see a reason for the universe to "end". There should be infinite empty space beyond what matter has filled (assuming the structure of the universe applies with most assumed rules of euclidian geometry, like that parallel lines will never intersect). However, that empty space is probably irrelevant because the universe will just collapse soon in a few <insert big number here> years. It will never expand past a certain size. Crap, everything we do is pointless unless we can invent inter-dimensional travel and save our asses from being crunched into a pinprick. Thinking about the cosmos always makes me depressed, I've never come to a happy conclusion when pondering the universe
The only thing that gives me hope for the future (very, very, very distant future) is the fact that maybe someday whatever sapient life form we have evolved to will be able to modify the laws of physics themselves. But then, maybe we will have broken the linear time perception barrier and the destruction of the universe will be irrelevant anyway. Now I'm really bummed out, I'm born in to a species that only became sapient a few million years ago :cryyy: does this stuff make anyone else sad?

 

[Alexizupinhea]

It does make me sad ossum^^. I'm confused if you're more sad that the universe is going to end (unless future species figure out a way to prevent it), or if you're sad that we will not live to see any "substantial" increase of our knowledge in the astronomy world (though I bet astronomers say otherwise). I'm most sad (not to bring up a whole new topic) that I will probably not live to see communication with other life forms out there (which I believe there definitely is, based on the number of galaxies, stars, and planets there are out there... and the odds that one would be set up "perfectly" like our mother earth)

 

[photonaholic]

I think our sun will go nova before the universe collapses, just my thought though.

and on the subject of lifeforms if "we" are the "best" the universe has to offer, that is sad.

 

[MrGreenJeans]

Yes, the sun will be long gone. Its existence will have represented only a blink of an eye when compared to the age of the universe when the universe reaches absolute zero. One of my favorite theoretical physicists is Michio Kaku. He's a very personable man who lives in the real world as opposed to many of the theoretical researcher I've come across. He discussed the fate of the universe from a non-collapsing perspective. I found it very interesting. I found a good description of the processes on Wiki although it leaves out a couple of eras but closely follows the talk.

Future of an expanding universe - Wikipedia, the free encyclopedia

When you think about it, it can be somewhat depressing but nothing in nature is specifically designed to raise the human spirit. The time line is immense to say the least.

 

[mfo]

I think our sun will go nova before the universe collapses, just my thought though.

and on the subject of lifeforms if "we" are the "best" the universe has to offer, that is sad.

Couldn't have said that better myself.

Yes, the sun will be long gone. Its existence will have represented only a blink of an eye when compared to the age of the universe when the universe reaches absolute zero. One of my favorite theoretical physicists is Michio Kaku. He's a very personable man who lives in the real world as opposed to many of the theoretical researcher I've come across. He discussed the fate of the universe from a non-collapsing perspective. I found it very interesting. I found a good description of the processes on Wiki although it leaves out a couple of eras but closely follows the talk.

Future of an expanding universe - Wikipedia, the free encyclopedia

When you think about it, it can be somewhat depressing but nothing in nature is specifically designed to raise the human spirit. The time line is immense to say the least.

Michio Kaku is my favorite also

 

[ninja_tux]

I think our sun will go nova before the universe collapses, just my thought though.

and on the subject of lifeforms if "we" are the "best" the universe has to offer, that is sad.

Our Sun actually isn't massive enough to ever supernova, it will get hotter and expand, eventually engulfing Mercury and incinerating the Earth's surface making in uninhabitable. When the Sun finally uses up all the fusionable material such that it isn't efficient any longer, it will blow off it's outer layers of gas (really plasma) and become a little white dwarf. This should all start to happen in about 5 billion years, so I very much doubt humans in the traditional sense will be around

 

[ossumguywill]

It does make me sad ossum^^. I'm confused if you're more sad that the universe is going to end (unless future species figure out a way to prevent it), or if you're sad that we will not live to see any "substantial" increase of our knowledge in the astronomy world (though I bet astronomers say otherwise). I'm most sad (not to bring up a whole new topic) that I will probably not live to see communication with other life forms out there (which I believe there definitely is, based on the number of galaxies, stars, and planets there are out there... and the odds that one would be set up "perfectly" like our mother earth)

All three of those make me sad.

I think our sun will go nova before the universe collapses, just my thought though.

and on the subject of lifeforms if "we" are the "best" the universe has to offer, that is sad.

Yep, the earth will be useless 5 billion years from now. But in the next few thousand, we will have left. The question is, can we leave the universe? But by the time it collapses, I'm sure whatever creature we have evolved to will have something figured out... like I said, maybe natural time travel. I believe Einstein said that our linear perception of time can be beaten, so that we can go to any moment in our lives, like the aliens kurt vonnegut's "slaughterhouse 5". At that point death will be irrelevant.

 

[StardustSprinkles]

I believe it is infinite. Assuming that the big bang theory is correct, I think that it is an infinintely exploding explosion that will keep going forever. It is everything we are and everything we know.

 

[Cenobite9]

Huh? So each "planet" would have its own universe? Where would these planets exist then?

No, think of it more as the universe being spherical in nature and all of the planets, galaxies, stars, etc. existing on the 'surface' of this sphere. In a case like that there would be no end as one would just continuously go around the surface. Of course that's only an unproven theoretical view of what the universe might be. I've watched enough of those Science channel specials about the universe to know that no one really knows and we'll probably never find out. Those scientist guys have some really bizarre and wonderful theories about the universe though...

 

[ossumguywill]

No, think of it more as the universe being spherical in nature and all of the planets, galaxies, stars, etc. existing on the 'surface' of this sphere. In a case like that there would be no end as one would just continuously go around the surface. Of course that's only an unproven theoretical view of what the universe might be. I've watched enough of those Science channel specials about the universe to know that no one really knows and we'll probably never find out. Those scientist guys have some really bizarre and wonderful theories about the universe though...

That also means that euclidean geometry is incorrect, and parallel lines can intersect at some point. There are all kinds of theories for the shape of space-time, euclidean, spherical, toroidal, conical, etc.
It could also mean that the shortest distance between two points is not, in fact, a straight line, rather a line which appears curved to us but is in fact a shorter distance that takes us outside of the norms of space-time. In fact, if the universe lied on a spherical plane and we could go through the sphere we could cut travel distance by up to ∏/2 times, I think.

 

[MrGreenJeans]

If we look at the law of universal gravitation we know that regardless of the distance between masses there is some gravitational influence, albeit very very weak at galactic distances. This law describes the influence of gravity. When we look at relativity we find that gravity is represented by warped space-time. Knowing that every object affects every other object in the universe inversely proportional to the distance squared we an postulate that the shape of space-time is no where near flat and most likely not spherical. It is a convoluted, twisting 4-dimensional entity with no consistent shape or central frame of reference. Stepping outside of basic physics and mathematics we begin to enter the realm of manifolds to describe various components of space-time.

In the early 1900s there were several observations of eclipses to verify Einstein's theory of general relativity (the melding of universal gravitation and special relativity). Basically they were verifying gravitational lensing due to warped space-time. As it was clearly verified we are left with a non-euclidean universe. If, while traveling on the a light ray you encounter a sufficient gravitational field the ray would bend to follow the warp of space-time. From your reference point, however, you would appear to continue in a straight line, never feeling any effects of inertial change as there is no inertial change.