ASTR 1504/1514: Astronomy: Exploring the UniverseMidterm Exam 21. Which of the following contributes most to the large difference in the average daytimeand nighttime temperatures on the Moon?• A: The lack of a hydrosphere• B: The lack of a magnetosphere• C: The lack of a n atmosphere• D: The lack of geologic activity2. Why did the terrest r i al planets l ose their pr i m ar y atmospheres?• A: Their low gravities couldn’t hold them.• B: The solar wind blew them away.• C: Their high surface temperat u r es made them chemically react with rock.• D: The centrifugal force from their fast rotation rates made them fly off.3. Venuss surface temperature is fairly uniform from the equator to the poles because:• A: Venus rotates very rapidly, which causes strong zonal winds• B: Venus is covered by a thick cloud layer that absorbs most of the sunlight thatfalls on it• C: the carbon dioxide in Venuss atmosphere efficiently emits infrared radiation• D: Venus rotates slowly so Coriolis forces do not disrupt Hadley circulation4. Which component in our atmosphere is a direct consequence of the emergence of life.• A: Carbon dioxide• B: Water vapor• C: Nitrogen• D: Oxygen5. The gas giants are composed primarily of:• A: hydrogen• B: helium• C: water• D: ammonia6. The compositions of Uranus and Neptune differ primarily from that of Jupiter andSaturn in that th e outer two planets contain more:• A: hydrogen• B: helium• C: water ice• D: carbon dioxide7. Why are Jupiter and Saturn n o t perfectly spherical?• A: They formed from the collision of two large planetesim al s.• B: They rotate rapidly.• C: They have storms that develop preferentially along their equators.• D: They have very active aurora e that heat the atmosph e r es along the poles.8. As a group, which is the following describes the rotation of gi ant planets compared toterrestrial planets.• A: faster than• B: slower than• C: the same as• D: retrograde compared to9. What is the most common geologic feature seen on moons?• A: Craters• B: Volcanoes• C: Palimpsests• D: Geysers10. Which p r operty of a moon might l ea d you to believe it was a captu r ed asteroid?• A: It is tidally locked.• B: Its orbital axis is tilted by 10 degrees compared to the planets rotational axis.• C: It rotates clockwise around the planet when viewed from the planets northpole.• D: Its surface is very smooth and lacks craters.11. Meteorites a r e more likely to come from asteroids than comets.• A: True• B: False12. All meteor i t es are remnants of planetesimals that never coalesced to form a planet.• A: True• B: False13. A parsec is a unit of time.• A: True• B: False14. The absolu t e magnitude of a star is a measure of its luminosity.• A: True• B: False15. Stars wit h a higher apparent brightness are necessarily closer to us than fainter stars.• A: True• B: False16. How many arcseconds are there in a degree?• A: 60• B: 360• C: 3,600• D: 6,00017. When an electron moves from a higher energy level in an atom to a lower energ y level:• A: the atom is ionized• B: a continuous spectrum is emitted• C: a photon is emitted• D: a photon is absorbed18. Star A is a red star. Star B is a blue star. Which is hotter?• A: Star A• B: Star B• C: We also need to know the luminosi t ie s of the stars to d et er m i n e their temper-atures.• D: Color is not related to temperatur e at all.19. The spectral class of a star is related to its:• A: luminosity• B: temperature• C: radius20. Stars are made mostl y of:• A: helium• B: oxygen• C: hydrogen• D: nitrogen21. In the quantum m echanical view of the atom, an electron is b est thought of as:• A: a cloud that is centered on the nucleus• B: a pointlike particle orbiting the nucleus• C: free to orbit at any distance from the nucleus• D: all of the above are t r ue22. Binary star systems are extremely useful in studying stars because they allow us todetermine st a r s masses.• A: True• B: False23. Which se qu ence correctly lists t h e spectral classes of stars in order of decreasing tem-perature (from hottest to coolest)?• A: A B F G K M O• B: O A B G F M K• C: A F O B M G K• D: O B A F G K M24. When looking at a standard H- R d i ag r am , the hottest stars are on the left-hand sideof the diagram.• A: True• B: False25. Main-sequence stars range in mass from approximately:• A: 0.5 to 10 M⊙• B: 0.08 to 140 M⊙• C: 1 to 100 M⊙26. In our Sun , hydrostatic equilibrium exists only in the core, where energy productionvia fusion can balan ce gravity.• A: True• B: False27. In the proton-proton chain, the net result is that 4 protons are converted into 1 heliumnucleus an d energy, positrons, and neutrinos are released.• A: True• B: False28. In the rad i at i ve zone inside the Sun, ph ot ons are transported from the core to theconvective zone in a matter of seconds.• A: True• B: False29. Our Sun is uniqu e compared t o the other stars in our galaxy because of its:• A: temperature• B: size• C: evolutionary stage• D: proximity30. The majority of the Sun s energy comes from:• A: gravitational contraction• B: its rapid rotation• C: hydrogen fusion• D: helium burning31. Neutrinos are particles with small masses that interact easily with normal matter.• A: True• B: False32. The solar neutrino problem was solved by postulating that neut r i n os have a small massand oscilla te between three different types of neutrino.• A: True• B: False33. The temperatu r e of the corona is much hotter than any other layer in the solar atmo-sphere.• A: True• B: False34. Which of the following methods is least import a nt to tr an s port ener gy from the coreto the surface of the Sun?• A: Radiation• B: Convection• C: Conduction35. Sunspots app ear dark because:• A: they have lower densities• B: they have lower rotation rat es• C: they have lower temperatures• D: they are storm systems like those on the Jovian