The redshift of the galaxies is correctly interpreted as
A) the differences in temperatures and star formation in old and young galaxies.
B) a Doppler shift due to the random motions of galaxies in space.
C) an aging of light as gravity weakens with time.
D) space itself is expanding with time, so the photons are stretched while they travel through space.
E) placing our Galaxy near the center of the Local Group.
D
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What is the thermosphere?
A) the lowest layer in the atmosphere B) the part of the atmosphere that absorbs optical light C) the part of the atmosphere that absorbs ultraviolet D) the part of the atmosphere that absorbs X-rays E) the highest layer in the atmosphere
If the Moon is setting at noon, then it rose at
A) midnight. B) 9 A.M. C) 6 P.M. D) 6 A.M. E) noon.
Energy provided directly from Earth's interior is called
a. groundwater energy. b. geothermal energy. c. artesian energy. d. thermionic energy.
An object is discovered near the earth with values of 2E/m = 2.12 × 107 m2/s2 and L/m = 7.8 × 1010 m2/s. This object is in what kind of orbit around the earth?
A. Elliptical B. Parabolic C. Hyperbolic