• Dear physicists...
    8 replies, posted
What if it is not universe expanding that causes the redshift, but light itself loses energy (frequency) after it travels a very long way?
:psyboom:
Magicks
[QUOTE=TheKnowItAll;25567790]:psyboom:[/QUOTE] Avatar fits [editline]22nd October 2010[/editline] No pun intended
[QUOTE=Nikita;25567633]What if it is not universe expanding that causes the redshift, but light itself loses energy (frequency) after it travels a very long way?[/QUOTE] Because the distance is irrelevant. It's only the direction of which the source is traveling which is. So if you had two stars at exactly the same distance from Earth, but one of them was moving towards us and the other away, the light would be perceived as different between the two. This despite the fact that the light has travelled exactly the same distance. So therefore redshift doesn't have to do with light losing energy over distance.
[QUOTE=Codename 47;25568097]Avatar fits [editline]22nd October 2010[/editline] No pun inteded[/QUOTE] Why thank you good sir :golfclap:
Two camels in a tiny car
[QUOTE=Rad McCool;25568497]Because the distance is irrelevant. It's only the direction of which the source is traveling which is. So if you had two stars at exactly the same distance from Earth, but one of them was moving towards us and the other away, the light would be perceived as different between the two. This despite the fact that the light has travelled exactly the same distance. So therefore redshift doesn't have to do with light losing energy over distance.[/QUOTE] Actually the further something is away from us, generally the more red shifted it is. It is the 'space' in between which is expanding. The more space = more redshifting of the frequency. OP's logic is sound (to an extent). It's like saying 'how do we know the universe is expanding and not just that we are shrinking'. Both are kinda the same thing really when you have no external frame of reference to judge it against. I guess the only way to know for sure is to keep an eye on the horizon of the universe and see if any new galaxies eventually pop into view. If they do, then this would show it to be expanding. If not then OP could be right. This would take millions of years of looking though.
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