How do we know that galaxy clusters contain a lot of mass in the form of hot gas that fills spaces between individual galaxies?
A) We detect this gas with x-ray telescopes.
B) We infer its existence by observing its gravitational effects on the galaxy motions.
C) The hot gas shows up as bright pink in visible-light photos of galaxy clusters.
D) We can observe the frictional effects of the hot gas in slowing the speeds of galaxies in the clusters.
A) We detect this gas with x-ray telescopes.
You might also like to view...
Based on all we know about the terrestrial worlds, what single factor appears to play the most important role in a terrestrial planet's geological destiny?
A) its size B) its composition C) its distance from the Sun D) whether or not it has liquid water
How do we know that the interior of jupiter is a liquid metallic material?
What will be an ideal response?
Water comes down the spillway of a dam from an initial vertical height of 170 m. What is the highest possible speed of the water at the end of the spillway?
a. 5.89 m/s b. 18.4 m/s c. 57.7 m/s d. 1 670 m/s e. 3 330 m/s
During a single period, the distance traveled by a wave is
A) one-half wavelength. B) one wavelength. C) two wavelengths. D) more information is needed