Chapter 11 Flashcards
Why was the newtonian view of the universe problematic?
His idea that all of the stars were bound to each other by gravity meant that the world would collapse on itself.
How could Newton’s theory work?
The stars were bound by equal gravitation on all sides. This was a far too delicate of a balance
What is escape velocity?
The velocity required for something to leave the atmosphere of a planet/star/black hole etc
What happens if the universe has negative net energy?
It cannot escape its own gravity and will collapse back on itself
What happens if the universe has positive net energy?
It can escape its own gravity and will continue to expand forever
What happens if the universe has zero net energy?
It will expand but eventually slow and stop
What shape of the universe does Newtonian gravity apply to?
Closed/spherical
What is ‘k’ in the Robertson-Walker metric?
the curvature constant
What are the 3 values of ‘k’?
1
-1
0
What does the Friedmann Equation solve for?
The rate of expansion of the universe
What makes up cosmic background radiation?
Leftover photons from the Big Bang
What are standard models?
the simplest of universe models that obeys the conservation of mass/energy, suntan some specified total mass-energy density, and have a cosmological constant of 0
What do we know about the rate of expansion for standard models?
It is getting decelerating. All universes that follow the standard model of gravity will decelerate
What does R equal when t=0?
0
What will a flat model of the universe do?
expand forever, but eventually slow
