The 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 2
What 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.
Emperor penguins with their black and white plumage stand out against the snow and colonies
Jets Created by a Black Hole in a Binary System
The black-and-white colobus is an African colobine.
Use of a hand tool to apply pressure to a trigger point.
Find an equation of the tangent line to the graph of f(x) = sqrt(x) / (x+1) at the point x=1
Mass spectrometry (MS) patterns for a trypsin-digested peptide sequence