Size of the universe?

[PainefulTruth]

Ok, light and matter have a definite speed limit that can't be exceeded. But the expansion of the universe can cause the distance between very remote objects to increase at rates greater than the speed of light. A quirk in the structure of the universe allows us to see a few photons left behind as expansion of space between these objects begins to exceed the speed of light. The expansion does continue to increase so that no such photons are "leaked" out. So we don't know how fast and far objects have expanded past our observable horizon.

My question for anyone out there who might have the information, when, between the first Planck Time and today, did the rate of expansion between any two distant objects first equal light speed? Put another way, when did the expansion between any two parts of the universe first accelerate so that the expansion caused each to "disappear" from the other? I think theories about the ultimate size of the universe currently lie between 90 billion light years into the trillions of light years. The problem is we don't know the principle behind the dark energy causing the expansion. But if we knew when the universe expansion did first reach light speed, we might be able to extrapolate it out to indicate the size of the universe today. (When I say "we" I am of course referring to the mankind collectively "we" )

 

[hangover]

The universe isn't big enough, so science now says there are multiple universes. Someday they'll figure out how we can transport ourselves on a thought beam. Thoughts go at the speed of light, don't they?

 

[IlarMeilyr]

The size of the universe is not a constant.

It is expanding. At one point long ago, it was the size of the pinpoint from whence emerged all of everything.

Getting from one end of the universe to the other in those days was FAST!

 

[rdean]

The universe isn't big enough, so science now says there are multiple universes. Someday they'll figure out how we can transport ourselves on a thought beam. Thoughts go at the speed of light, don't they?

No, they don't. Try to figure out why.

 

[hjmick]

Bigger than a bread box...

 

[rdean]

bigger than this?

 

[hangover]

The universe isn't big enough, so science now says there are multiple universes. Someday they'll figure out how we can transport ourselves on a thought beam. Thoughts go at the speed of light, don't they?

No, they don't. Try to figure out why.

Duh, gee mister wizard, "Slower minds keep right."?

 

[Steven_R]

Ok, light and matter have a definite speed limit that can't be exceeded. But the expansion of the universe can cause the distance between very remote objects to increase at rates greater than the speed of light. A quirk in the structure of the universe allows us to see a few photons left behind as expansion of space between these objects begins to exceed the speed of light. The expansion does continue to increase so that no such photons are "leaked" out. So we don't know how fast and far objects have expanded past our observable horizon.

My question for anyone out there who might have the information, when, between the first Planck Time and today, did the rate of expansion between any two distant objects first equal light speed? Put another way, when did the expansion between any two parts of the universe first accelerate so that the expansion caused each to "disappear" from the other? I think theories about the ultimate size of the universe currently lie between 90 billion light years into the trillions of light years. The problem is we don't know the principle behind the dark energy causing the expansion. But if we knew when the universe expansion did first reach light speed, we might be able to extrapolate it out to indicate the size of the universe today. (When I say "we" I am of course referring to the mankind collectively "we" )

We really don't know any of those answers. The observable universe is a sphere about 46 billion light years in diameter. Each direction we can see light is 13.8gyr old, plus we add in what we know about rate of expansion. Is the universe actually larger than the observable universe? We just don't know. Is it finite or infinite or something else? Maybe, maybe not depending on which version of the math you agree with.

As to when after the Big Bang did expansion outpace light, we don't know that either, in large part because we don't know the mechanism behind it or the limits of the universe. It would be like trying to figure out the average speed of a car on a trip when you know when it left, but not when it got to the destiniation, don't know the route, and find out the route it did take added in a few miles at some point. Figuring out Dark Energy will go a long way towards defining some of the variable involved and then maybe we can go from there.

It's both frustrating that we don't know and terribly exciting that there is so much left to discover.

 

[Politico]

No one knows and no one ever will.

 

[Spiderman]

No one knows and no one ever will.

And it doesn't really matter if we ever find out. That is until we develop faster than light travel.

 

[Politico]

Exactly. And that won't happen either in any of our lifetimes.

 

[PainefulTruth]

The universe isn't big enough, so science now says there are multiple universes.

While not disproven, I think the many worlds quantum interpretation has fallen out of favor along with the Copenhagen interpretation. Ultimately we have no idea what our universe is expanding into, and if there are multiverses, might they not just be part of an ultimate cosmos.

The size of the universe is not a constant.

As would be the case if the universe is expanding as it is now, or contracting.

We really don't know any of those answers. The observable universe is a sphere about 46 billion light years in diameter. Each direction we can see light is 13.8gyr old, plus we add in what we know about rate of expansion. Is the universe actually larger than the observable universe? We just don't know. Is it finite or infinite or something else? Maybe, maybe not depending on which version of the math you agree with.

And to be specific, the oldest light we can see is 13.7 billion years old, but it was emitted by an object that space has expanded so as to make it 23 billion light years away from us--thereby stretching and reddening that light in the process. In 3 trillion years, all but our local gravity bound galaxies will be carried by space that is expanding away from us faster than light and thus be invisible. And the radius of the observable universe is 43 billion light years because we can still observe light "leaking" back towards us from objects being carried by space as it begins to surpass the speed of light.

As to when after the Big Bang did expansion outpace light, we don't know that either, in large part because we don't know the mechanism behind it or the limits of the universe. It would be like trying to figure out the average speed of a car on a trip when you know when it left, but not when it got to the destiniation, don't know the route, and find out the route it did take added in a few miles at some point. Figuring out Dark Energy will go a long way towards defining some of the variable involved and then maybe we can go from there.

It seems that since we can see things for a time after they become superluminal, that we could pinpoint what the time is (was) when that happens.

It's both frustrating that we don't know and terribly exciting that there is so much left to discover.

True.

No one knows and no one ever will.

Famous last words.

 

[flacaltenn]

The universe isn't big enough, so science now says there are multiple universes.

While not disproven, I think the many worlds quantum interpretation has fallen out of favor along with the Copenhagen interpretation. Ultimately we have no idea what our universe is expanding into, and if there are multiverses, might they not just be part of an ultimate cosmos.

The size of the universe is not a constant.

As would be the case if the universe is expanding as it is now, or contracting.



And to be specific, the oldest light we can see is 13.7 billion years old, but it was emitted by an object that space has expanded so as to make it 23 billion light years away from us--thereby stretching and reddening that light in the process. In 3 trillion years, all but our local gravity bound galaxies will be carried by space that is expanding away from us faster than light and thus be invisible. And the radius of the observable universe is 43 billion light years because we can still observe light "leaking" back towards us from objects being carried by space as it begins to surpass the speed of light.



It seems that since we can see things for a time after they become superluminal, that we could pinpoint what the time is (was) when that happens.

It's both frustrating that we don't know and terribly exciting that there is so much left to discover.

True.

No one knows and no one ever will.

Famous last words.

That large bolded part above COULD BE a convienient and Occam style explanation for the predominance of "dark matter" constituting the bulk of the mass of the universe. Instead of a mysterious different form of energy --- it COULD BE just energy that has "cloaked" itself in stealthy speed.

As for the answer to your question.. My girlfriend says "Its THIS BIG"...

 

[PainefulTruth]

Women instinctively understand relativity. What she's saying is, "Men think this is 6 inches!"