Author Question: What distance method did Edwin Hubble use to determine the distance to local galaxies? a. Hubble ... (Read 117 times)

melly21297 · **on:** Jul 27, 2018

What distance method did Edwin Hubble use to determine the distance to local galaxies?

a. Hubble law
b. supernova observations
c. period-luminosity relationship of variable stars
d. parallax

Question 2

Why is there a lower end to the main sequence?

What will be an ideal response?

Brenm · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

c

Answer to Question 2

The mass-luminosity relation tells you why the main sequence must have a lower end. Low-mass objects have lower pressures and temperatures in their cores, and those with less than about 0.08 solar mass are too cool to allow hydrogen fusion.