posted by Dre on .
Which of the following distance measuring techniques works to measure distances to other galaxies beyond the Milky Way? CHECK ALL THAT APPLY
A) Hubble's Law
B) main sequence stars
C) Cepheid variable stars
E) radar ranging
F) galaxy rotation
G) white dwarf supernovae
I believe the answers are B, C, and G. Could someone please tell me if I'm right and explain this to me?
A) will give an approximate value for distant galaxies. Close galaxies can vary a lot from the Hubble relation because of local velocity differences. (Out nearest glaxy is actually getting closer and will eventually collide with the Milky Way!) By the way, Hubble's "Law" is not considered a law. It is an approximately linear relation between velocity and distance, based on a curve fit to scattered data.
C) is a good answer
G) would be OK is it just said "supernovae", but white dwarfs do not become supernovae
The other choices are nonsense.