The density of the Universe is a. equal to the critical ...

[olgavictoria]

The density of the Universe is
 
  a. equal to the critical density if the Universe is closed.
  b. equal to the critical density if the Universe is flat.
  c. greater than the critical density if the Universe is flat.
  d. greater than the critical density if the Universe is open.
  e. None of the other choices are correct.

Question 2

If white dwarfs have exhausted their fuel, why are they hot?
 
  What will be an ideal response?

[kalskdjl1212]

Answer to Question 1

b

Answer to Question 2

When a star collapses into a white dwarf, it converts gravitational energy into thermal energy. Its interior becomes very hot.

[olgavictoria]

Both answers were spot on, thank you once again

[kalskdjl1212]

Great! Please up vote