How do Stefan's law and a knowledge of Earth's history tell us that the Sun's temperature cannot have varied much in the last 3.5 billion years?
What will be an ideal response?
Question 2Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates?
A) The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.
B) Being on a high mountain top means being relatively high in the atmosphere, which tends to limit turbulence.
C) Dry regions mean less rain and clouds, and mountaintops in dry regions may even allow some infrared observations.
D) Mountaintops far from cities are generally subject to less light pollution than locations nearer to cities.
Question 3Most of first extrasolar planets found were detected by
A) noting the drop in the star's light as the planet transits its disk.
B) imaging them with the HST in the infrared, where they are easier to stop.
C) noting the Doppler shifts of the star as the planet orbits it from side to side.
D) receiving radio transmissions from them, much like Jupiter emits.
E) detecting the oxygen in their atmospheres spectroscopically.
Question 4The energy in the atmospheres of most of the jovian planets comes
A) almost entirely from the Sun.
B) almost entirely from their interiors.
C) both the Sun and their interiors, in roughly equal proportions.
D) tidal heating.
Question 5When new particle pairs are being created as fast as they annihilate, it is:
A) hydrostatic equilibrium.
B) thermal equilibrium.
C) the threshold equilibrium.
D) the cosmological constant.
E) the critical density.
Question 6The direction of the rotation of Venus is exceptional because it is in a(n) ________ direction.
Fill in the blank(s) with correct word
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