ASTR Exam 3 PDF

What are the main constituents of Earth’s atmosphere? Every time a comet gets near the Sun, some of its material a. hydrogen and helium streams away in the tail. Shouldn’t all comets be gone? b. nitrogen and oxygen...

What are the main constituents of Earth’s atmosphere? Every time a comet gets near the Sun, some of its material a. hydrogen and helium streams away in the tail. Shouldn’t all comets be gone? b. nitrogen and oxygen a. no, the comet material accretes again after leaving the Sun c. oxygen and carbon dioxide b. yes, but there are more comets stored in “deep freeze” d. oxygen and carbon monoxide e. water vapor and oxygen beyond Pluto c. not yet, but they will all be gone sometime in the near future Why is atmospheric pressure less on top of a mountain than at sea level? What class of bodies does Pluto most resemble? a. It is cooler in the mountains. a. a major planet b. Denser air sinks to sea level; the air on mountains is b. a large Kuiper belt comet lighter. c. an asteroid c. The pressure at every height in the atmosphere is due to the weight of the air above it. d. None of the above. Why do some comets come from far out in space and from all different directions (i.e., not in the plane of the solar system)? a. They come from other solar systems. If there were no greenhouse effect, Earth would b. They come from nebulae in interstellar space. a. be warmer than it is today. c. They come from a giant spherical cloud called the Oort cloud. b. have a thicker atmosphere. d. They come from the Kuiper belt when a comet is flung out by c. be colder than freezing. Neptune’s gravity. d. have no protection from ultraviolet radiation. About how often is it estimated that an asteroid or comet If Earth were more reflective (had a higher albedo), what impacts Earth with sufficient energy to cause mass extinction? would happen to its temperature? a. once a millennium a. It would go up. b. once every million years b. It would go down. c. once every hundred million years d. once in Earth’s history c. It wouldn’t change. Would it be plausible to discover that a small asteroid orbiting If Earth didn’t have an atmosphere, what would happen to within the asteroid belt has an active volcano? its temperature? a. Plausible. Several small objects in the solar system have a. It would go up a little. active volcanoes. b. It would go up a lot. b. Plausible. Several asteroids are known to be composed of c. It would go down a little. d. It would go down a lot. e. It basaltic material (lava). wouldn’t change. c. Implausible. Only planets, not moons or asteroids, have volcanoes. d. Implausible. Asteroids are too small to be geologically active It is typically colder on clear nights than on cloudy nights. now. a. Yes, the clouds produce heat, warming the surface of the Earth. b. Yes, the water within the clouds acts as an effective Why are there very few asteroids beyond Jupiter's orbit? greenhouse “gas.” A. There was no rocky material beyond Jupiter's orbit. c. No, clouds have nothing to do with temperature. B. The heaviest rocks sank toward the center of the solar d. No, the clouds are higher density and therefore produce system. a lower temperature in the atmosphere. C. Ice could form in the outer solar system.  D. A passing star probably stripped away all of those asteroids, even if they were there at one time. Which gases within our atmosphere act as greenhouse gases? a. water Which explanation for the belt seems the most plausible? b. carbon dioxide A. The belt is where all the asteroids happened to form. B. The c. oxygen and nitrogen d. all of the above belt is the remnant of a large terrestrial planet that e. a and b used to be between Mars and Jupiter. C. The belt is where all the asteroids happened to survive. But Why didn't they form a planet? Which of the following correctly arranges the layers of Earth’s atmosphere from closest to the surface to closest to space? What determines the direction of a comet's tail? a. troposphere, stratosphere, exosphere, thermosphere A. The tail extends behind the comet as it moves across the b. stratosphere, exosphere, thermosphere, troposphere solar system. c. troposphere, stratosphere, thermosphere, exosphere d. B. The tail extends in front of the comet as it moves across the thermosphere, troposphere, stratosphere, exosphere solar system C. The tail extends away from the direction of the Sun. D. The tail is randomly oriented since there is nothing in Infrared radiation emitted by Earth’s surface space that acts as a wind. a. heats the troposphere from below. b. causes convection. c. causes weather (storms). d. all of the above. Is it possible to photograph a planet orbiting around another e. none of the above. star? a. Yes, but with a large telescope because the planet would be faint. The stratosphere is heated by b. No, because the brightness of the star would overwhelm the a. warm air rising from the troposphere. planet. b. ultraviolet light from the Sun. c. Yes, but a space telescope would need to be used so that the c. convection. scattered light from the star would be minimized. d. x-rays. e. all of the above. In order to maximize your chance of seeing a faint, cooler planet next to a brighter, hotter star, you should observe in The sky is blue because a. visible light. a. of the reflection of the oceans. b. ultraviolet light. c. infrared light. d. x-ray light. b. blue is the color of oxygen gas. c. blue is the color of nitrogen gas. d. the blue light in sunlight scatters more than the red light. To detect an extrasolar planet by means of the Doppler shift, e. of clouds. you look for a periodic shift of the spectrum lines of the a. star the planet is orbiting. b. planet. What protects Earth from the high energy particles ejected c. star and the planet. from the Sun (the solar wind)? a. the troposphere b. the stratosphere The orbital period of an unseen planet will be c. the exosphere a. the same as the period of the star’s Doppler shift. d. the magnetosphere b. much longer than the star’s. c. much shorter than the star’s. e. the Van Allen radiation belts The shorter the period of the Doppler curve, What affects the global circulation pattern of Earth’s a. the closer the unseen planet is to the star. atmosphere? b. the farther the unseen planet is from the star. c. the greater a. hot air from the equator rising and cool air at the poles the mass of the planet. falling d. the smaller the mass of the planet. b. Earth’s rotation c. convection e. a and c. d. the Coriolis effect e. all of the above The larger the mass of the unseen planet, What affects long-term climate change? a. the larger the Doppler shift of the star. a. changes in the Sun’s brightness b. the smaller the Doppler shift of the star. b. changes in Earth’s reflectivity c. the faster the period of the star’s Doppler shift. d. the slower c. change in the tilt of Earth’s axis the period of the star’s shift. d. changes in greenhouse gas abundance e. all of the e. a and c. above Suppose you found a star similar to the Sun moving back and What was the source of the atmospheres we see today? forth with a period of 2 years. What could you conclude? a. gas accreted from the solar nebula a. It has a planet orbiting at less than 1 AU. b. comets b. It has a planet orbiting at greater than 1 AU. c. gas released from interior rocks (outgassing) d. c. It has a planet orbiting at exactly 1 AU. evaporation from ice d. It has a planet, but we don’t know its mass so we can’t know its orbital distance for sure. Where did the carbon dioxide in Earth’s atmosphere go? a. We never had any. Jupiter is about 1/10 the diameter of the Sun. If it transited, how b. It escaped into space. much would the Sun’s light dim? c. It dissolved in the oceans and was incorporated into a. about 10% (it would be 90% of its regular brightness) rocks. b. about 1% (it would be about 99% its regular brightness) d. None of the above. c. about 30% (it would be about 70% of its regular brightness) d. about 50% (it would be about half its regular brightness) Do the Moon and Mercury have an atmosphere? a. No, they entirely lost their atmospheres early on in their Our theory of solar system formation predicts that large, formation. gaseous planets form far from their star. How can we explain b. Yes, they are very low-density atmospheres though. the extrasolar hot Jupiters that are close to their stars? c. Yes, they have an atmosphere just like other terrestrial a. Our theory is wrong. planets. b. Large planets do form far from their star, but their orbits can change due to gravitational encounters with other objects. c. Large planets do form far from their star, but waves of Why do we think Mars was once warmer and wetter? material can pull on planets and alter orbits. a. It has plenty of volcanoes to outgas an atmosphere. d. b and c. b. It doesn’t have a strong magnetic field to protect it from solar wind stripping. c. There is evidence it once had liquid water. It is too cold Space missions are currently underway or planned to for that now. a. search for Earth-sized planets transiting stars. d. All of the above. b. search for wobbles in stars caused by planets much less massive than Jupiter. c. attempt to take direct images of extrasolar planets. What is the main reason that Venus is warmer than Earth? d. all of the above. a. The Sun’s light is stronger for Venus since it is closer to the Sun than Earth. b. Venus has a higher reflectivity than Earth. How do astronomers look for planets whose orbits might cause c. Venus has a lower reflectivity than Earth. them to pass in front of a star outside our solar system? d. The greenhouse effect is much stronger on Venus than a. They look for a small black dot passing in front of the star. on Earth. b. They look to see if the star’s position shifts or “wobbles” e. Human presence on Earth has led to declining slightly in the sky. temperatures. c. They measure the star’s brightness, and look for periodic dimming (transits). What would happen to Earth’s atmosphere if we moved it to Venus’s orbit? Suppose an alien was discovering the existence of Earth via a. The atmosphere would be blown away by the solar wind. the transit method. Where on the celestial sphere would the b. The greenhouse effect would runaway on Earth and it alien's exoplanetary system have to be? would become Venus-like. Suppose an alien was discovering the existence of Earth via the c. Nothing would change. transit method. Where on the celestial sphere would the alien's exoplanetary system have to be? A. Near the northern polar star Polaris Suppose that, somehow, all plants died out. What would B. Near a southern polar star Sigma Octantis C. Along the happen to the oxygen in our atmosphere? celestial equator a. The oxygen would eventually be used up in chemical reactions with the surface. b. The oxygen would initially decrease, but as greenhouse Suppose you found a star with the same mass as the Sun gases and temperature increased, it would recover to its moving back and forth with a period of 16 months. What could normal value. you conclude? c. The oxygen would increase as plants would not exist to A. It has a planet orbiting at less than 1 AU. remove it from the atmosphere. B. It has a planet orbiting at greater than 1 AU. d. Plants grow by intaking carbon and therefore the oxygen C. It has a planet orbiting at exactly 1 AU. content would be unaffected. D. It has a planet, but we do not have enough information to know its orbital distance. Would it be plausible for a planet that had an Earth-like atmosphere with plentiful oxygen, but no life of any kind, to What happens in a gravitational encounter that allows a exist in another solar system? planet's orbit to move inward? a. Plausible. Life requires far more than oxygen to exist. A. It transfers energy and angular momentum to another object. b. Plausible. The oxygen may have been transported there B. The gravity of the other object forces the planet to move by cometary impacts. inward. c. Implausible. Oxygen is highly reactive and its presence in C. It gains mass from the other object, causing its gravitational an atmosphere suggests replenishment by a living pull to become stronger. organism of some sort. d. Implausible. Oxygen is essential to life. If it is expected that each star within the Milky Way has at least one planet, about how many planets would there be in this single galaxy?  Why do Jupiter, Saturn, Uranus, and Neptune all have A. One million (1,000,000) rings? B. One-hundred million (100,000,000) a. They were left over from solar system formation. C. One billion (1,000,000,000) b. They all captured particles. D. One-hundred billion (100,000,000,000) c. All four planets had a large moon that disintegrated. d. All have small moons and orbiting particles that constantly collide and make rings. Why does the Sun shine? a. it is on fire b. chemical energy Saturn’s average density is less than water’s. Suppose c. gravitational energy d. nuclear fusion Saturn were placed on a much larger planet made entirely e. nuclear fission of water. What would happen? A. Itwouldsinktothecenterofthewaterplanet. B. Itwouldbespreadoutduetotherotationofthewaterplanet. Why is the Sun very dense on the inside? C. Itwouldmergeintothewaterplanet;densermaterials sinking a. Denser materials sank to its center. toward the core and lighter materials forming part of the b. Weight of the outer layers gas keeps the density high. atmosphere. c. It formed from dense material. D. TherewouldbeadevastatingimpactandSaturnwouldbe d. The photon pressure at the center is very high, increasing the torn apart to form a giant ring system around the water overall density. planet. What conditions are required for nuclear fusion of hydrogen to What is a key difference between the two planets Jupiter occur? and Saturn and the two planets Neptune and Jupiter? a. a temperature of millions of Kelvin and high density a. Size b. a temperature of millions of Kelvin and low density c. the b. Composition presence of uranium c. Mass d. all of the above d. Color e. All of the above. What is a hydrogen nucleus—the particle that fuses into helium in the Sun? If Jupiter were the size of a basketball, Earth would be the a. a neutron size of a(n) b. a proton a. bacterium. b. grain of rice. c. marble. c. an electron d. a positron d. orange. e. grapefruit. If the Sun’s core went out of balance and shrank a little, what would happen? About how long does it take a spacecraft to go from Earth a. The density and temperature would decrease, and fusion to Jupiter? would slow down, releasing less energy. a. a week b. The density and temperature would increase, and fusion b. a month would speed up, releasing more energy. c. a year c. The whole Sun would shrink. d. Not much would change. d. several years e. several decades If the fusion in the Sun’s core sped up slightly, releasing more Jovian planets energy, what would happen? a. have rings and large numbers of moons. a. The core would contract. b. all have many moons, but only Saturn has rings. b. The core would expand. c. have moons, but Uranus and Neptune have only one or c. The color of the Sun would change. two. e. are massive and rotate slowly. How do photons get through the Sun’s radiation zone? a. They bounce from atom to atom, being absorbed and What is the structure of Jupiter like? reemitted as they make their way to the surface. a. thin atmosphere, rocky core b. They are brought to the surface by conduction. c. They are b. thick atmosphere, rocky core brought to the surface by convection. c. gaseous on the outside, then liquid hydrogen, more dense metallic hydrogen, rocky core d. gaseous on the outside, then liquid hydrogen, then By the time photons reach the surface of the Sun helium, then the other elements (photosphere), they are mostly a. infrared light. b. visible light. What are the most common elements in the atmospheres c. ultraviolet light. d. x-rays. of Jupiter and Saturn? e. gamma rays. a. water b. hydrogen and helium c. oxygen and nitrogen d. oxygen and carbon e. none of the If we can’t see the Sun’s interior, how do we know what it is above like? a. observations of sunquakes b. observations of neutrinos c. computer modeling What are the most common hydrogen compounds in the d. all of the above atmospheres of the jovian planets? a. water (H2O), methane (CH4), ammonia (NH3) b. water and carbon dioxide (CO2) The Sun’s visible surface, or photosphere, has lower c. water and carbon monoxide (CO) temperature regions of strong magnetic field called d. sulfur dioxide (SO2) and propane (C3H8) e. none of the a. granulation. above b. magnetic traps. c. magnetic lines. d. sunspots. e. sundogs. Since there are a lot of flammable gases on Jupiter, such as methane and propane, if you lit a match, would Jupiter Since the Sun’s outer atmosphere, or corona, is millions of burn? degrees but not very dense, a. yes a. we can’t really detect it in any wavelength. b. we detect it very b. no clearly in visible light. c. we detect x-rays coming from it. Convection circulates gases from deep in Jupiter’s atmosphere to the top, where they What is the sunspot cycle? a. escape into space. a. the balance of pressure and gravity in the Sun’s core b. condense and make bubbles. c. condense and make b. the process of fusing hydrogen into helium clouds. d. form plasma. c. the 11-year cycle of changes in the occurrence of sunspots, flares, and solar wind d. the process by which photons from the Sun’s core make their Jupiter does not have a large metal core like Earth. How way to the surface can it have a magnetic field? a. The magnetic field is left over from when Jupiter accreted. How can a coronal mass ejection from the Sun affect Earth? b. Its magnetic field comes from the Sun. a. It can make beautiful auroras. c. It has metallic hydrogen inside, which circulates and b. It can cause geomagnetic storms. c. It can damage satellites. makes a magnetic field. d. It can disrupt electrical power. d. It has a large metal core. e. All of the above. Auroras near the poles of the planets Which of the following can be used to directly measure the a. are found on Earth. Sun’s mass? b. are found on Jupiter. a. solar luminosity and Earth-Sun distance c. indicate the presence of a magnetic field. b. solar temperature and Earth-Sun distance d. occur when particles in the solar wind hit a planet’s c. solar rotation rate and Earth-Sun distance atmosphere. d. Earth’s mass and the orbital period of Earth around the Sun e. all of the above. e. Venus’s orbital period and distance from the Sun What is the weather usually like on Jupiter? If fusion in the solar core ceased today, would worldwide panic a. high speed winds, low density clouds break out tomorrow as the Sun began to grow dimmer? b. low speed winds, high density clouds a. Yes, because Earth would quickly freeze over. c. winds of hundreds of miles per hour, thick clouds d. clear b. Yes, because Earth would no longer be bound to the solar and very cold system and would drift into space. c. Yes, because the Sun would collapse and the planets would soon follow. Jupiter is about three times as massive as Saturn, but only d. No, it takes thousands of years for photons created in nuclear slightly larger. Why? reactions at the solar core to reach the surface. a. It is made of denser material. e. No, the Sun would continue to glow brightly for billions of b. It is made of less dense material. years because of gravitational contraction. c. Adding mass increases gravity and compresses the interior. d. They are made of different gasses. e. None of the above. True or False? If you want to see a lot of sunspots, just wait for the time of solar maximum. a. True, the number of sunspots peaks at solar maximum. Looking at a jovian planet in different wavelengths of light b. False, the number of sunspots peaks at solar minimum. allows us to c. False, the number of sunspots is random and does not a. see different kinds of clouds. depend on whether it is the time of solar minimum or maximum. b. see to different depths in the atmosphere. c. see layers of different temperatures. d. all of the above. What two properties of Earth are necessary to use Newton's e. a and b. version of Kepler's third law to determine the mass of the Sun? A. Earth's radius and mass B. Earth's orbital radius and mass What is the most geologically active object we know of in C. Earth's orbital radius and orbital period D. Earth's radius and the solar system? orbital period a. Earth b. Mercury c. Mars d. Jupiter e. Io What would happen inside the Sun if a slight rise in core temperature led to a rapid rise in fusion energy?  A. The core would expand and heat up. How does Io get heated by Jupiter? B. The core would expand and cool. a. auroras C. The Sun would blow up like a hydrogen bomb. The solar b. ultraviolet radiation c. infrared radiation d. tidal heating thermostat keeps burning rate steady. What would increase the tidal heating of a moon? a. a more elliptical orbit b. a larger size c. a larger companion planet d. all of the above How does the energy Jupiter radiates back to space compare to the energy from the Sun that falls on it? This photograph shows the Space Shuttle orbiting about 300 a. Jupiter gives off more than it receives. kilometers above Earth's surface. What is the significance of the b. Jupiter gives off about as much as it receives. c. Jupiter whitish glow around the Shuttle's tail? gives off less than it receives. A) It shows that Earth's atmosphere still exists, though thinly, at this altitude. B) It shows that the Space Shuttle can cause auroras along its How do astronomers think Jupiter generates internal heat? orbit. a. fusion C) It shows that the Shuttle was firing its engines at the time this b. chemical reactions photo was taken. c. friction due to its fast rotation D) It shows that the Shuttle lights work in space as well as they d. shrinking and releasing gravitational potential energy e. work on the ground. tidal heating Titan is the only moon with a thick atmosphere, and its surface a. has never been seen. b. has been seen by infrared light and spacecraft. c. is warmed by a greenhouse effect. d. has oceans of liquid methane and ethane. e. all except a. What shape are moons? a. nearly spherical b. large ones are spherical; small ones are irregular c. small ones are spherical; large ones are irregular What does this diagram represent? d. Earth’s and Jupiter’s moons are spherical; Uranus’s and A) the basic way in which the greenhouse effect works Neptune’s are not B) the carbon dioxide cycle C) the basic reason that our sky is blue D) the basic mechanism of the Coriolis effect Why can icy moons be geologically active when a planet the same size would be “dead?” a. Planets are older, so they have already cooled off. b. Ice melts and deforms at a lower temperature than rock, making geological activity easier. c. Many have tidal heating caused by their planet. d. All of the above. e. b and c. Asteroids a. are rocky and small–typically the size of a grain of rice or What does this figure tell us? a marble. A) The current level of carbon dioxide in our atmosphere is b. are rocky, with a wide range of sizes, up to hundreds of higher than it has been at any time during the past 800,000 miles in diameter. years. c. have only thin atmospheres. B) Earth is now warmer than it has been at any time during the d. are made mostly of metals. past 800,000 years. e. are mostly found in the inner solar system. C) The current level of carbon dioxide in our atmosphere can be attributed to natural changes in Earth's climate. D) The level of carbon dioxide in our atmosphere changes If you keep pushing a person on a swing with little pushes, randomly with time, so there is no way to predict how it will at just the right frequency, they will swing very high. This is change during the next century. an example of E) The current level of carbon dioxide in the atmosphere and a. Newton’s second law. b. Newton’s first law. the global average temperature are both higher today than at c. energy conservation. d. resonance. any other time during the past 800,000 years. e. conservation of angular momentum. Orbits of asteroids in the asteroid belt a. usually intersect the orbits of the planets. b. are mostly between Mars and Jupiter. c. are grouped into patterns by resonances with Jupiter. d. are mostly inside the frost line. e. all except a. What is the best way to find the density of an asteroid? a. Look at its spectrum. b. Study a sample of its matter. c. Find an asteroid with a moon and use Kepler’s third law. d. None of the above. Each white dot in this figure represents the location of a small body in our solar system. The donut-shaped ring of white dots represents the region of our solar system that we call Most meteorites come from A) the asteroid belt. a. stars. B) the Kuiper belt. b. destroyed planets. C) the Oort cloud. c. asteroids. D) the Sun's rings. d. the Moon and Mars. e. material ejected from volcanoes.  Comets a. formed from planetesimals in the inner part of the early solar system. b. formed from planetesimals in the outer part of the early solar system. c. orbit the Sun and return time after time, for billions of years. d. have a single tail that streams out straight behind them. The nucleus of a comet a. is made of rock. b. is made of dust and ice, like a dirty snowball. c. releases plasma when the comet nears the Sun. This graph shows the frequency of impacts on Earth by objects of various sizes. According to this graph, objects large enough to cause a mass extinction hit Earth If Earth passed through the tail of a comet, what would A) about once every 50 million years. happen? B) about once every 1,000 years. a. People would die from the gasses such as methane and C) about once in Earth's history. ammonia. D) about once every 500 million years. b. Earth would be bombarded by large impactors. c. Earth might be knocked out of its orbit or its axis might get tilted. d. A meteor shower would occur. Why is there a meteor shower every year on Aug. 10, 11, and 12? a. Meteorites only enter the solar system on certain dates. b. Meteorites often have 1 year orbital periods. This diagram represents a star with an orbiting planet that, as c. Earth passes through the orbit of a comet and hits the seen from Earth, periodically transits across the face of the star remaining debris at the same time each year. and disappears behind the star. If you measure the brightness d. None of the above. of this system, at which point would it be brightest? A) Point 1 B) Point 2 Why do comet tails always point away from the Sun? C) Point 3 a. They are left behind as the comet moves. D) Point 4 b. Newton’s third law: If the comet goes one way, the tail must go the other way. c. The solar wind blows them away from the Sun. d. They don’t; this is just a perspective effect of how we view them.  Each dot on this graph represents an extrasolar planet detected over about a four-year period by the Kepler This graph shows the brightness of a star over the course of a mission. Suppose the mission had been able to continue transit. Which of the following do we learn about the planet? collecting data for many more years. How would you expect A) It is large enough to block about 2.5% of the star's light. the graph to look different in that case? B) It has an orbital period of less than 2 hours. A) Additional dots would be found further to the right. C) It is about 2.5% as massive as the star. B) Additional dots would be found above the existing dots. D) It is about 97.5% as bright as its star. C) Additional dots would be found further to the left. D) All the existing dots on the graph would move diagonally up and right.