Redshift and Hubble constant

  • #1
Which statement is true?

A The apparent speed of recession of a galaxy is given by the product of the Hubble constant and the distance to the galaxy.

B The further away a galaxy is, the lower its apparent speed of motion away from us.

C A galaxy with a redshift of 5.37 is situated at a look-back time of 4.1 billion years.

D Space is expanding uniformly so that the distance between galaxies remains constant.
 

Answers and Replies

  • #2
negitron
Science Advisor
842
1
Which statment(s) do you think is/are true and why?
 
  • #3
I think statement A is true but I'm not 100% sure whether D is false and there is only one true statement.
 
  • #5
negitron
Science Advisor
842
1
Well, isn't it generally true that the farther a galaxy is from us, the faster it appears to be receding?
 
  • #6
Yeah, I didn't think B or C were the answers.
I'm still stuck between whether A or D is the right answer and I really need help.
 
  • #7
cepheid
Staff Emeritus
Science Advisor
Gold Member
5,192
38
Does it make any sense for the distance between things to remain constant in an *expanding* universe???

When we say that a galaxy is moving away from us, what does that mean? Does it not mean that it is getting farther away with time?
 
  • #8
Statement A is definitely correct.
 

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