Planet Redshift?

Question

Why are planets with red shift at the speed of light are said they are at the edge of the known universe. My physics teacher confuse me so I hate asking him.

Ah yeah i meant galaxies sorry lol.

Thanks tastywheat, you answer explains it all. Now I will have less chance of failing my exam ^_^

Answer 1

If you think of the universe as an expanding plumb pudding, then the galaxies further away from us are moving away more quickly than the nearer galaxies/stars. The red shift is due to the Doppler effect - the faster things move away from us, their natural frequency appears to be lower. In sound, this shows itself as a note lower in pitch than the original: in light, it shows as a shift towards the red (i.e. lowever frequency) end of the light spectrum.

Answer 2

First, you will never see a planet at the edge of the known universe, since it is too far.

The crux of the statement is that objects at the edge of the universe appear to be speeding up, so they exhibit a blue shift. However, a planet of a star has to rotate TOWARDS us some of the time, so it would show a red shift.

Answer 3

I'm assuming that by "planets" you mean "galaxies"...

Since the universe is expanding at an accelerating rate, galaxies that are farther away from us are moving faster than galaxies that are closer to us.

The limit of this is where galaxies are moving at the speed of light (relative to us). This causes these galaxies to be completely redshifted (practically invisible). This logical "barrier" forms the edge of the known (observable) universe.

Answer 4

Hey if your tutor is confusing you,tell him . it is not good for either your education or his tutoring,all tutors should be aware of each student and check their understanding,if this is some personality problem,either nip it in the bud or get another course/tutor.(you have your answer from the 1st answer Tastywheat)(maybe your enquiring mind is better served here!)

Answer 5

dunah x