According to Kepler's third law, calculate the orbital period of a planet approximately 6.0 AU away from the Sun.
a. 6 years
b. 15 years
c. 30 years
d. 36 years
e. 214 years
Question 2The event horizon of a black hole is the point where _____.
a. the mass of the black hole is concentrated in a singularity
b. the accretion disk around the black hole contacts its surface
c. the escape velocity equals the speed of light
d. tidal forces ionize infalling gas
e. an infalling particle reaches equilibrium with radiation pressure
Question 3What was Eratosthenes's mathematical contribution to the history of astronomy, even though it was incorrect?
a. He calculated the diameter of Earth by what he learned from travelers' itineraries.
b. He estimated Earth's revolution rate by measuring the length of shadows casted on the surface.
c. He determined that all the planets orbited Earth every 24 hrs.
d. He attempted to calculate Earth's radius by utilizing the position of sunlight.
e. He believed all of nature was underlain by musical principles.
Question 4A stellar core with a mass greater than 3 solar masses will collapse until it reaches _____.
a. the radiusof Earth
b. the radius of Mt. Everest
c. the radius of a grain of sand.
d. the radius of a helium atom
e. a radius of zero