- #1
Xtyn
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How do you define "at rest" in the Universe?
I was reading in a Scientific American an article called: "Misconceptions about the Big Bang" By Charles H. Lineweaver and Tamara M. Davis.
In it I found this:
Individual galaxies move around at random within clusters, but the clusters of galaxies are essentially at rest. The term "at rest" can be defined rigorously. The microwave background radiation fills the universe and defines a universal reference frame, analogous to the rubber of the balloon, with respect to which motion can be measured.
How can you measure motion in respect to microwave background radiation?
Also, I was drawing something and I want to know if it is correct.
The "0" 's are bodies, "-" is a photon.
Each row is a year.
Because of space expansion, the bodies are increasing their distance (relative to one another) at the speed of light.
The bodies are at first 3 light-years apart.
......0-...0
......0...-...0
........0...-...0
.......0...-..0
......0...-.0
......0...-0
......0.....0
Although the bodies were 3 light-years apart, the photon arrived in 6 years from the first to the second body and it shows the first body as it was 6 years ago. When the photon arrives, the bodies are now 9 light-years apart.
So, the photon traveled 6 light-years.
Is this correct?
Can those bodies be "at rest"? If not, my calculations are wrong, because if they move through space, time gets dilated.
I was reading in a Scientific American an article called: "Misconceptions about the Big Bang" By Charles H. Lineweaver and Tamara M. Davis.
In it I found this:
Individual galaxies move around at random within clusters, but the clusters of galaxies are essentially at rest. The term "at rest" can be defined rigorously. The microwave background radiation fills the universe and defines a universal reference frame, analogous to the rubber of the balloon, with respect to which motion can be measured.
How can you measure motion in respect to microwave background radiation?
Also, I was drawing something and I want to know if it is correct.
The "0" 's are bodies, "-" is a photon.
Each row is a year.
Because of space expansion, the bodies are increasing their distance (relative to one another) at the speed of light.
The bodies are at first 3 light-years apart.
......0-...0
......0...-...0
........0...-...0
.......0...-..0
......0...-.0
......0...-0
......0.....0
Although the bodies were 3 light-years apart, the photon arrived in 6 years from the first to the second body and it shows the first body as it was 6 years ago. When the photon arrives, the bodies are now 9 light-years apart.
So, the photon traveled 6 light-years.
Is this correct?
Can those bodies be "at rest"? If not, my calculations are wrong, because if they move through space, time gets dilated.