Spiral density wave theory and self-sustaining star formation are ways to explain why ____.
a. stars orbit the galaxy with different periods at different distances from the center
b. sun-like stars are evenly distributed through the disk of the galaxy
c. dark matter affects the orbit of stars outside the visible disk of the galaxy
d. molecular clouds are compressed forming young stars along spiral arms
e. the central bulge of the galaxy has a bar shape
Question 2
One of the first tests of the general theory of relativity was the ____.
a. description of the orbit of the moon
b. determination of the speed of light as a constant
c. change in mass of a particle moving at a high speed
d. demonstration of a hammer and a feather falling at the same rate on the moon
e. determination of the rate of advance of the perihelion of Mercury's orbit
Center of Mass of a Binary Star System
Theory of Endosymbiosis
Tornado Formation: Supercell Tornado Development
Theory of Plate Tectonics
Tornado Formation
Gastrulation and the onset of organ formation.