Expansion of the universe Flashcards
1
Q
Why do stars rotate?
A
galaxies rotate about their cores
2
Q
How does distance affect velocity of star
A
stars on outer arm of galaxy should travel slower than those closer to galactic core as experience smaller gravitational force of attraction
3
Q
Mass of galaxy can be determined using what?
A
orbital speed of stars within it
4
Q
What is dark matter?
A
amount of matter in galaxies that we cannot see
5
Q
the rate of expansion is?
A
increasing
6
Q
What is dark energy?
A
force acting against gravitational attraction
