The amount of dark matter in the universe is
A) about the same as the amount of visible matter.
B) many times more than the amount of visible matter.
C) about twice as much as the amount of visible matter.
D) many times less than the amount of visible matter.
E) entirely unknown at the present time.
Question 2
By observing gas clouds orbiting the centers of galaxies, we have learned that galaxies are made mostly of dark matter. In these observations
A) the light from the gas clouds is obscured by some unseen material.
B) the low speeds of the gas clouds show that they are being slowed by some unseen material.
C) the high speeds of the gas clouds show that they are being pushed by some unseen material.
D) the low speeds of the gas clouds show that they are gravitationally attracted to the center by unseen material.
E) the high speeds of the gas clouds show that they are gravitationally attracted to the center by unseen material.
The small dorsal fin of this blue whale is just visible on the far left.
White matter
Big Picture of the Evolution of the Universe
Gray Matter Development over the Surface of the Cortex
Find the final amount if the initial amount is 400 units.
The Universe According to Ptolemy, Second Century A.D.