Does size matter?

[PhantomLlama]

Isn't there a theory which states that the universe is finite but also edgeless, because it curves round on itself in the 4th space dimension?

It also explains why there is no center to the universe.

 

[Jet Black]

the uncertainty principle is really for quantum objects, it doen't have much to say here.

remember when we look at the sky, we are looking back in time. so when we look at alpha centauri, that is what it looked like 4 years ago, and when we look at andromeda, that is what it looked like three million years ago.... the furthest we will be able to see is 13.7 billion years, because that is the point at which the universe became transparent.

 

[PhantomLlama]

I always find it odd to think that the sun could have exploded seven minutes ago and we still wouldn't know about it.

(I know there is no concievable mechanism for the sun actually exploding seven minutes ago, but it is still odd)

 

[Nathan Poe]

I always find it odd to think that the sun could have exploded seven minutes ago and we still wouldn't know about it.

(I know there is no concievable mechanism for the sun actually exploding seven minutes ago, but it is still odd)

If we found out in advance, there might be just enough time to prepare a special news bulliten about it.

Basically Tom Brokaw coming on the air and telling us all to kiss our ***es goodbye

 

[webboffin]

Nathan, I know you already know this, but we'd only have an advantage of a few minutes warning if we knew before hand when the Sun was going to explode. Finding out in the after event would be too late to report as we'd all know in any case no matter where you were in Earth or space because the information would be travelling at the speed of light.

 

[JohnR7]

Nathan, I know you already know this, but we'd only have an advantage of a few minutes warning if we knew before hand when the Sun was going to explode.

If russia ever sends their atomic bombs up over the north poll you may only have two or three hours warning. Or should I say when they decide to blow us up, we will not have much warning

So, do you think the government should warn us, or just let the chips fall where they may? Of course you only have to worry about it if you live within 50 miles of one of the 100 biggest cities. If your 50 miles away, then you at least have a 50 - 50 chance of survival.

Their bombs are not known to be accurate though. Who knows, maybe they will miss the city all together.

 

[Gracchus]

It is a matter of scale.

"Isaac Asimov has a dramatic illustration: it is as fi all the matter of the universe were a single grain of sand, set in the middle of an empty room 20 miles long, 20 miles wide and 20 miles high. Yet at the same time, it is a if that single grain of sand were pulverized into a thousand million million million (10^21, or ten to the 21st power--Gracchus) fragments , for that is approximately the number of stars in the universe. These are some of the sobering facts of astronomy, and you can see that they are beautiful."

Dawkins, Richard "Unweaving the Rainbow: Science, Delusion and the Appetite for Wonder" (c) 1998 Richard Dawkins, Houghton Mifflin Co.

 

[ObbiQuiet]

the uncertainty principle is really for quantum objects, it doen't have much to say here.

It DOES have direct aplications to things we observe/interact with.

For instance: Say we are observing an animal. Your mere presense there may cause the animal to act differently then it would had you not been there. Or lets say you are measuring something with a ruler (I know humans cannot be this accurate, but still) just by you applying the ruler to the object you may change the object's length.

Anyway. Just something kinda cool I thought of a while ago.

 

[Gracchus]

As I understand it, the universe may be unbounded in three dimensions but bounded in the fourth, time. It is in the fourth dimension that it is expanding, and so its radius is not properly given in lightyears, which is a measure of spacial dimension but in units of time.
Thus, the radius of the universe would be about thirteen and a half billion years.

 

[webboffin]

What if the universe was totally void of anything living and of conscious; no observer; no thought; no awareness. Would it exist?

 

[lucaspa]

For the observable universe, that is about right. 2 times the age of the universe light years from one direction to the other. But, AFAIK (and IANA Astrophysicist), there is no reason to think the whole universe is finite. The space at the edge of our observable universe doesn't appear to be special in anyway, like it is near an edge.

There is every reason to think the whole universe is finite. After all, spacetime also came into existence at the BB. Therefore there is a finite amout of spacetime out there. Why would there be an "edge"? An edge implies a discontinuity between two parts of space. Since all there is of spacetime is what is in the universe, the spacetime anywhere in the universe is going to be similar.

 

[lucaspa]

It DOES have direct aplications to things we observe/interact with.

For instance: Say we are observing an animal. Your mere presense there may cause the animal to act differently then it would had you not been there.

True, but the disturbance has nothing to do with QM.

Or lets say you are measuring something with a ruler (I know humans cannot be this accurate, but still) just by you applying the ruler to the object you may change the object's length.

Uh, no. Because the wave function of uncertainty regarding length of any macroscopic line is so much smaller than an atom that no measuring device could detect the difference.

There is nothing in the macroscopic world that has an uncertainty large enough that observation would affect it in any way that could be detected in the macroscopic world.

 

[MartinM]

There is every reason to think the whole universe is finite. After all, spacetime also came into existence at the BB. Therefore there is a finite amout of spacetime out there

While there are non-trivial topologies which allow flat or open Universes to be finite in spatial extent, the simplest models are indeed infinite. Since observation shows the Universe to be at least very nearly flat, there's good reason to leave open the possibility of an infinite Universe.

 

[JohnR7]

There is every reason to think the whole universe is finite.

Our universe. Perhaps there is an infinite number of universes.

 

[ThePhoenix]

If russia ever sends their atomic bombs up over the north poll you may only have two or three hours warning. Or should I say when they decide to blow us up, we will not have much warning

So, do you think the government should warn us, or just let the chips fall where they may? Of course you only have to worry about it if you live within 50 miles of one of the 100 biggest cities. If your 50 miles away, then you at least have a 50 - 50 chance of survival.

Their bombs are not known to be accurate though. Who knows, maybe they will miss the city all together.

Accuracy with nukes aint much of a problem. Did you land within two miles of the target? Direct hit.

 

[pudmuddle]

What if the universe was totally void of anything living and of conscious; no observer; no thought; no awareness. Would it exist?

If a tree falls in the woods and no one is there....

If there was no conscious observer, meaning no ultimate power holding it all together, it would have never existed.
If God could die, and did, it would probably explode into chaos and self destruct.

 

[Nathan Poe]

Accuracy with nukes aint much of a problem. Did you land within two miles of the target? Direct hit.

Did you land within a hundred miles upwind of the target? Close enough. It's just take a little longer...