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marcus

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its routine in mainstream cosmology that much of space expands away from us faster than the speed of light

A poster (DrChinese) back in PF Astro "Archive" was inquiring about this---it was in the "Superluminal Recession Speeds". If you want, we could carry on the discussion out here rather than back in Astro Archive.

The paper we were discussing was Davis and Lineweaver

"Superluminal Recession Velocities"

http://arxiv.org/astro-ph/0011070 [Broken]

A more recent and complete discussion is in Lineweaver's

"Inflation and the CMB"

http://arxiv.org/astro-ph/0305179 [Broken]

To get an idea of the magnitudes, the CMB has redshift 1100

and the highest observed redshift of a quasar is 6.4

A great many objects have z > 2. How many? I dont know but the volume in which objects have redshift 2 or greater is more than 95 percent of the volume of the observable universe.

I'll check that with Wright's "cosmocalculator" and be back.

http://www.astro.ucla.edu/~wright/CosmoCalc.html

It is very handy, you just type in a value for z and select the "flat" button----it uses the most recent values of the hubble parameter and for dark energy, to calculate the distance and light travel time and so forth, from the redshift z you put in.

You might want to translate some observed redshift like z = 3 into a recession speed----how fast was the object receding at the time the light was emitted and how fast is it currently receding?

If so ask about it (several people around here can explain) or if you know you might want to explain how its calculated yourself.

A poster (DrChinese) back in PF Astro "Archive" was inquiring about this---it was in the "Superluminal Recession Speeds". If you want, we could carry on the discussion out here rather than back in Astro Archive.

The paper we were discussing was Davis and Lineweaver

"Superluminal Recession Velocities"

http://arxiv.org/astro-ph/0011070 [Broken]

A more recent and complete discussion is in Lineweaver's

"Inflation and the CMB"

http://arxiv.org/astro-ph/0305179 [Broken]

To get an idea of the magnitudes, the CMB has redshift 1100

and the highest observed redshift of a quasar is 6.4

A great many objects have z > 2. How many? I dont know but the volume in which objects have redshift 2 or greater is more than 95 percent of the volume of the observable universe.

I'll check that with Wright's "cosmocalculator" and be back.

http://www.astro.ucla.edu/~wright/CosmoCalc.html

It is very handy, you just type in a value for z and select the "flat" button----it uses the most recent values of the hubble parameter and for dark energy, to calculate the distance and light travel time and so forth, from the redshift z you put in.

You might want to translate some observed redshift like z = 3 into a recession speed----how fast was the object receding at the time the light was emitted and how fast is it currently receding?

If so ask about it (several people around here can explain) or if you know you might want to explain how its calculated yourself.

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