Hubbles law isaac physics help!

https://isaacphysics.org/questions/phys19_k1_q6?board=ab9d1012-b7db-4dcb-ba2d-3de8289978cf&stage=a_level
I got the answer to the first part but got 6500 for the second and it says its wrong
I calculated (-393.4*10^-9+3.94*10^-7)/(393.4*10^-9)*3*10^8/70=6536 Mpc
Thank you!

(edited 1 year ago)

Reply 1

Joseph McMahon

Original post by MayaVellichor

Reading this it appears you have greatly overcomplicated what is involved.

You are asked for: the distance between the Earth and the Galaxy. Hubble's Law provides a relationship between the recessional velocity of a galaxy and the distance it is from Earth. You are given a value to use for H and already have recessional velocity.

Pay attention to the units you have available in the question and make sure you choose the right option when checking your answer.