Just because a star is 13b lya doesn't mean it is 13b years old

[Realitycheck]

I read it all of the time in articles, about stars that "are from a time right after the big bang'. With so many tens and hundreds of billions of light years of space outside the visible universe, just how is it that anybody is able to see what should be dead information? If a star is supposedly 13b lya now, then it was probably 7b lya when a given snapshot was taken, give or take a few, and the difference is made up by the expansion of space over time. And if we can't see them now, then supposedly the james webb will help us see this first generation of occurrences, but i just don't see it because these things that happened 13b ya happened when the universe was only a fraction of its size now and the light from a snapshot such as that long ago would have reached all available points much long ago. It is dead information.

Edited December 26, 2010 by Realitycheck

[alpha2cen]

We think what we know about the Universe, i.e. present Universe knowledge, is not all right.

It's the middle stage to go to the perfect trouth.

The information for 13b lya away star ll be no useful about that star itself when we ll arrived there in the future .

But it can help us to understand about ourself, our Solar system and the Universe itself.

Edited December 26, 2010 by alpha2cen

[Sisyphus]

I read it all of the time in articles, about stars that "are from a time right after the big bang'. With so many tens and hundreds of billions of light years of space outside the visible universe, just how is it that anybody is able to see what should be dead information? If a star is supposedly 13b lya now, then it was probably 7b lya when a given snapshot was taken, give or take a few, and the difference is made up by the expansion of space over time. And if we can't see them now, then supposedly the james webb will help us see this first generation of occurrences, but i just don't see it because these things that happened 13b ya happened when the universe was only a fraction of its size now and the light from a snapshot such as that long ago would have reached all available points much long ago. It is dead information.

 

I'm having trouble parsing what it is you are suggesting. But, to be clear, when we see an event that occured 13 billion years ago (i.e. soon after the big bang), that object we are seeing was much closer than 13 billion light years away when the light we are seeing was emitted, and is much farther away than 13 billion light years away now, because of expansion. I don't know what you mean by "dead information."

[MR. Science]

Well first of all we need to cut the billions of years stuff out of the conversation, most people on this forum hasnt been around 60 years, so how can we say something is billions of years old, all we know is its old, real real old, and no something can be qaudrillions of light years away but only 25 human years old.

[D H]

Well first of all we need to cut the billions of years stuff out of the conversation ...

No, we don't. Just because you do not want to read the truth does not mean you get dictate the terms of the debate here.

 

 

 

most people on this forum hasnt been around 60 years, so how can we say something is billions of years old, all we know is its old, real real old, and no something can be qaudrillions of light years away but only 25 human years old.

Ummm, no.

 

 

The light we see now emitted by some object 13 billion years ago has been traveling for 13 billion years. This does not mean that the object was 13 billion light years away from us 13 billion years ago, nor does it mean that the object is 13 billion years away from us now. What it means is that the object was only 3.35 billion light years away from us 13 billion years ago and that it is now 29.7 billion light years away (comoving distance).

 

The above values were calculated assuming a flat universe, a Hubble constant H₀ of 71 (km/s)/Mpc, and a mass density Ω_M of 0.270. Those values for H₀ and Ω_M are from the seven-year long WMAP study. Different values will yield different results, but qualitatively they will be similar. The object was much closer to us 13 billion years ago than than that 13 billion years appears to suggest, and it is much further than 13 billion light years away from us now.

Edited January 18, 2011 by D H

[steevey]

I read it all of the time in articles, about stars that "are from a time right after the big bang'. With so many tens and hundreds of billions of light years of space outside the visible universe, just how is it that anybody is able to see what should be dead information? If a star is supposedly 13b lya now, then it was probably 7b lya when a given snapshot was taken, give or take a few, and the difference is made up by the expansion of space over time. And if we can't see them now, then supposedly the james webb will help us see this first generation of occurrences, but i just don't see it because these things that happened 13b ya happened when the universe was only a fraction of its size now and the light from a snapshot such as that long ago would have reached all available points much long ago. It is dead information.

 

I know that a star is some specific multiple of millions of light years away, but the only way to say "that star is 1 billion years old because its 1 billion light years away" is if the universe was always expanding at the exact speed of light. Since the universe has been expanding at slow, and maybe even faster rates than the speed of light, the distance doesn't equal the age.

[MR. Science]

Lets lock this thread up before it gets out of control.

 

 

[D H]

Out of control, how? By stating the best estimates science can give?

[Realitycheck]

No, we don't. Just because you do not want to read the truth does not mean you get dictate the terms of the debate here.

 

 

 

 

Ummm, no.

 

 

The light we see now emitted by some object 13 billion years ago has been traveling for 13 billion years. This does not mean that the object was 13 billion light years away from us 13 billion years ago, nor does it mean that the object is 13 billion years away from us now. What it means is that the object was only 3.35 billion light years away from us 13 billion years ago and that it is now 29.7 billion light years away (comoving distance).

 

The above values were calculated assuming a flat universe, a Hubble constant H₀ of 71 (km/s)/Mpc, and a mass density Ω_M of 0.270. Those values for H₀ and Ω_M are from the seven-year long WMAP study. Different values will yield different results, but qualitatively they will be similar. The object was much closer to us 13 billion years ago than than that 13 billion years appears to suggest, and it is much further than 13 billion light years away from us now.

Oh yeah, comoving distance. Thank you for your input DH. I should have worked harder at stating a question in English, but I knew that there were misunderstandings in the field, according to Martin's articles. So what this probably means is that the ever-so-popular WMAP representation of the expansion of the universe is drawn nowhere near to scale (no surprise there), that the rate of expansion is actually much closer to that which is depicted for inflation, and if you just add some practicality into your depiction of inflation, everything works out just fine. I guess whats hard to fathom is that the universe could be that big that long ago. Once you see that, then everything kind of falls into place. That's actually kind of hard to fathom again, that the universe grew to 3.5+ billion ly diameter in just 700 million years, so now we're back to the impossibilities of inflation, but I guess that is part of other threads. All that inflation stuff sounds like nothing more than a mathetical plug anyway. What if the "Big Bang" started from a big sphere of quark gluon plasma? What would keep everything pressurized, the confines of an unborn universe? Where would it come from? What would let everything go? Excess pressure against what wall?

Edited January 23, 2011 by Realitycheck

[Spyman]

Yes, it's hard to fathom how big the Universe is and it's hard to grasp how Nature behaves or to understand different scientific models of it.

 

AFAIK, there is nothing keeping everything pressurized, no walls confining the Universe with empty space outside and not any unborn universes, in mainstream cosmology.

 

We don't know how the Universe originated and from what or if the Universe has always been or what size it has.

 

Based on the best available measurements as of 2010, the most comprehensive and accurate explanation supported by scientific evidence and observations is that the Universe, from an extremely hot and dense state, 13.7 billion years ago, expanded rapidly and cooled to the present state.