The Naked Scientists

The Naked Scientists Forum

Author Topic: What does a redshifted Universe mean?  (Read 3915 times)

Offline shmengie

  • Jr. Member
  • **
  • Posts: 17
    • View Profile
What does a redshifted Universe mean?
« on: 28/04/2008 03:14:59 »
The further back in time we look, he more light is redshifted?  It seems to me that cosmologists believe this means the Universe is accelerating.

That logic does not make sense.  Quite the contrary, IMO, it means the universe is slowing down!

Further back you look the more it's red shifted == moving away faster longer ago.

The closer objects are the less light is shifted == they're moving away slower closer to present.

Doesn't that mean that the universe is expanding slower closer to present and the further back in time you go, the faster it expands?

Am I missing some piece of logic that states the further back in time you go the faster things are moving now?

I guess we're all in the dark, since light speed is light speed and we can't see the present 13.7 billion light years away.
« Last Edit: 02/05/2008 10:31:49 by chris »


 

Offline graham.d

  • Neilep Level Member
  • ******
  • Posts: 2208
    • View Profile
Re: What does a redshifted Universe mean?
« Reply #1 on: 28/04/2008 11:09:08 »
The calculations take this into account. It is sometime dangerous to just interpret the neat soundbytes :-)
 

Offline shmengie

  • Jr. Member
  • **
  • Posts: 17
    • View Profile
Re: What does a redshifted Universe mean?
« Reply #2 on: 29/04/2008 02:57:15 »
Does that mean that the light from the furthest objects is less shifted than some that are less distant?
 

Offline JP

  • Neilep Level Member
  • ******
  • Posts: 3366
  • Thanked: 2 times
    • View Profile
Re: What does a redshifted Universe mean?
« Reply #3 on: 29/04/2008 05:14:43 »
I know it's consistent with the models of the expansion of the universe that things farther away are MORE redshifted than things closer to us.  You get this same effect whether or not the universe is accelerating--it can be expanding at a constant rate and you still get this.

I would guess the cause is something like this:  As light travels, the fabric of the universe is stretching.  The light is therefore stretched out as well, as it has to travel on this fabric.  The longer the light spends traveling, the longer it has to be stretched, and the more redshifted it gets.
 

Offline shmengie

  • Jr. Member
  • **
  • Posts: 17
    • View Profile
Re: What does a redshifted Universe mean?
« Reply #4 on: 29/04/2008 09:30:41 »
Stretching the fabric or "ether" of space is the culprit of redshift.  Gravity can bend light.  Bending light will elongate it's wavelength, because it will travel a longer distance than if were traveling in a straight line.

As black holes develop they must concentrate more ether near the singularity.  As light travels through the emptiness of space, it's wavelength will elongated because there is less ether in the voids between galaxies than there are near the centers of galaxies.

This could be evidenced by a galaxy that is tilted toward us on an angle.  The stars on the far side and the stars on the near side would neither be moving away or toward us at a different rate, but the shift would be differentiated by the bend produced by blackhole in the center.


 

Offline LeeE

  • Neilep Level Member
  • ******
  • Posts: 3382
    • View Profile
    • Spatial
 

lyner

  • Guest
Re: What does a redshifted Universe mean?
« Reply #6 on: 01/05/2008 15:00:51 »
Quote
This could be evidenced by a galaxy that is tilted toward us on an angle.  The stars on the far side and the stars on the near side would neither be moving away or toward us at a different rate, but the shift would be differentiated by the bend produced by blackhole in the center.
Isn't this stuff all well documented?
 

Offline shmengie

  • Jr. Member
  • **
  • Posts: 17
    • View Profile
Re: What does a redshifted Universe mean?
« Reply #7 on: 02/05/2008 04:13:44 »
Isn't this stuff all well documented?
I'm suspect the Doppler effect, comparing stars on opposite sides of galaxies have been documented well. 

Since stars on the near and far sides of a galaxy should be moving the same rate toward or away from us, there might be little or no reason to document or search for a discrepancy if one exists.  It may be assumed that there will be no difference in the doppler effect on stars in near vs. far sides, so why bother. 

We know there should/will be a difference comparing the stars on the opposite sides perpendicular to our view, moving toward and away. 

There shouldn't be a difference for the ones on the near and far sides parallel to our view, those should be moving the same rate toward or away from us.  That wouldn't suggest which way a galaxy is spinning, but it would suggest that gravity can influence the doppler effect.

Is that documented?  If so, I would like to know.  Unfortunately, I expect the difference will be nominal, enough so that it may be difficult to document.

« Last Edit: 02/05/2008 04:37:58 by shmengie »
 

The Naked Scientists Forum

Re: What does a redshifted Universe mean?
« Reply #7 on: 02/05/2008 04:13:44 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums
 
Login
Login with username, password and session length