Astronomy Exam 4
A star is seen to move by 0.4 seconds of arc between March 1, 1999 and September 1, 1999 and then back to its starting point on March 1, 2000. What is the parallax angle for this star? (A) 0.2 seconds of arc. (B) 0.1 seconds of arc. (C) 0.3 seconds of arc. (D) 0.4 seconds of arc. (E) 0.8 seconds of arc.
(A) 0.2 seconds of arc. (half)
Our Sun is a G2V star with absolute magnitude 4.8. Suppose that a star of spectral type G2V is observed to have apparent magnitude -0.2. How far away is it? (A) 1 parsec. (B) 5 parsecs. (C) 10 parsecs. (D) 100 parsecs. (E) 1000 parsecs.
(A) 1 parsec.
Suppose that a flash of lightning from a cloud 5000 meters away is followed by a clap of thunder two seconds later. Assume that the light arrived in a negligible time and calculate the speed of the sound waves. (A) 2500m/s (B) 2m/s (C) 5000m/s (D) 1250m/s (E) 1000m/s
(A) 2500m/s
The red line of a spectrum is normally at a wavelength of 656 nm. In the light of a star that is moving toward us, we might expect to see that red line at a wavelength of (A) 650nm. (B) 656nm. (C) 660nm.
(A) 650nm.
A type M star that is known to have three terrestrial-size planets near its habitable zone is (A) Gliese 581. (B) GJ 486. (C) Alpha Centauri A (D) 51 Pegasi. (E) Epsilon Eridani.
(A) Gliese 581.
Which of the following statements best describes the presence of water on Mars? (A) Mars probably had liquid water flowing on its surface at some time in the past. (B) At the present time, Mars is completely without water in any form. (C) Mars has liquid water flowing steadily on its surface at the present time. (D) At the present time, Mars is completely covered by a thin layer of frozen water ice.
(A) Mars probably had liquid water flowing on its surface at some time in the past.
You see a telescope with a long tube and the eyepiece sticking out the side near the top. This telescope uses the (A) Newtonian Focus. (B) Cassegrain Focus. (C) Prime Focus. (D) Coudé Focus
(A) Newtonian Focus
Suppose that the color and behavior of a star identify it as a type that we know has absolute magnitude -3. If the star's apparent magnitude is found to be 2, how far away is it? (A) 5 parsecs. (B) 10 parsecs. (C) 50 parsecs. (D) 100 parsecs. (E) 1000 parsecs.
(D) 100 parsecs.
In a particular binary star system, we are able to determine the masses of both stars in the system as well as the angle between our line of sight and the plane of the stars' orbits but cannot determine the diameters or atmospheric compositions of the two stars. This system is most likely (A) a visual binary system. (B) a spectroscopic binary system. (C) an eclipsing spectroscopic binary system.
(A) a visual binary system.
Here is the Drake Equation: N = R*×fp×ne×fl×fi×fc×L In this equation, L stands for the (A) expected lifetime of a communication-capable civilization. (B) number of communication-capable civilizations in our galaxy. (C) average number of habitable planets in a planetary system. (D) number of extraterrestrial messages that we might expect to detect in a year.
(A) expected lifetime of a communication-capable civilization.
A main-sequence star with more mass than our sun will be (A) hotter and brighter. (B) cooler and dimmer. (C) cooler and brighter. (D) hotter and dimmer.
(A) hotter and brighter.
A star with an absolute magnitude of 5.7 and an apparent magnitude of -1.2 would appear in our sky as a star (A) of dazzling brightness. (B) of average naked-eye brightness. (C) barely visible to the naked eye. (D) visible only with a telescope.
(A) of dazzling brightness.
The main reason to suspect that Europa has a subsurface ocean of water is (A) patterns of cracks in the ice on its surface. (B) low fluxes of epithermal neutrons. (C) landmarks that are not rotating with the rest of the moon. (D) geysers of water shooting out through cracks in the moon.
(A) patterns of cracks in the ice on its surface.
A star of spectral type M should look (A) red. (B) orange. (C) yellow. (D) white. (E) blue.
(A) red.
Which of the following colors indicates the coldest star? (A) red. (B) blue. (C) yellow. (D) peach. (E) orange.
(A) red.
The wavelength of the sound waves that correspond to middle-C is about 4 feet. If you are standing 8 feet away from a piano that is playing that note, then between you and the piano there will usually be (A) two regions of maximum pressure. (B) one region of maximum pressure. (C) maximum pressure every two seconds. (D) three regions of maximum pressure. (E) maximum pressure every four seconds.
(A) two regions of maximum pressure.
Which of the following magnitudes corresponds to the dimmest star? (A) +3.4. (B) +5.6. (C) +2.1. (D) -1.5. (E) +1.2
(B) +5.6.
The distance modulus of a star at a distance of 10 parsecs would be (A) -5. (B) 0. (C) 5. (D) 10. (E) 15.
(B) 0.
A star is seen to move by 0.2 seconds of arc between February 1, 1999 and August 1, 1999 and then back to its starting point on February 1, 2000. What is the parallax angle for this star? (A) 0.2 seconds of arc. (B) 0.1 seconds of arc. (C) 0.3 seconds of arc. (D) 0.4 seconds of arc. (E) 0.5 seconds of arc.
(B) 0.1 seconds of arc. (half)
A star with a distance modulus of zero is at a distance of (A) 1 parsec. (B) 10 parsecs. (C) 100 parsecs. (D) 1000 parsecs. (E) 10,000 parsecs.
(B) 10 parsecs.
Barnard's star shows a proper motion of 10.36 arc seconds per year. In 100 years, its position in the sky changes by (A) 10.36 seconds of arc. (B) 1036 seconds of arc. (C) 0 seconds of arc. (D) 103.6 seconds of arc. (E) 518 seconds of arc.
(B) 1036 seconds of arc.
The star 36-Ophiuchus is six parsecs from our Sun. The light from this star in the "serpent holder" constellation has been traveling for approximately (A) 6 years. (B) 20 years. (C) 0.55 years. (D) 1.8 years. (E) 12 years.
(B) 20 years. (6x3.3)
The star pi3-Orionis is 8 parsecs from our Sun. The light from pi3-Orionis has been traveling for (A) 8.0 years. (B) 26 years. (C) 0.4 years. (D) 2.4 years. (E) 0.125 years.
(B) 26.4 years. (8x3.3)
The star delta-Eridani shows a heliocentric stellar parallax of almost exactly 1/9 seconds of arc. The distance from our Sun to delta-Eridani is (A) 1/9 parsecs. (B) 9 parsecs. (C) 4.5 parsecs. (D) 18 parsecs. (E) 4 parsecs.
(B) 9 parsecs. (1/1/9) = 9
Which of the following discoveries would lead to the conclusion that the universe is probably filled with life, both in our own solar system, and in the planetary systems of other stars? (A) A few microbes with Earth-type DNA/RNA biochemistry are found beneath the soil of Mars. (B) A few microbes with a completely alien biochemistry are found beneath the soil of Mars. (C) No trace of life is found anywhere on Mars.
(B) A few microbes with a completely alien biochemistry are found beneath the soil of Mars.
Which of the following requirements for life appears to lacking on the planet Mars? (A) A portable form of carbon. (B) A global carbon-return process. (C) An energy source for life. (D) liquid water.
(B) A global carbon-return process.
Which of these is a statement of the Fermi Paradox? (A) We are never special. (B) Any long-lasting technological civilization should be obvious and might even be visiting us, so where are they? (C) The strength of an interstellar signal falls off as the square of the distance but the expected number of such signals increases as the square of the distance, so where are they? (D) Because time in a moving reference frame is much slower than in the rest frame, aliens can get anywhere they want to in a very short amount of their own time, so where are they? (E) Not only do you never get more than you pay for, you never break even.
(B) Any long-lasting technological civilization should be obvious and might even be visiting us, so where are they?
Which of the following spectral classes corresponds to the highest surface temperature (on this list)? (A) A (B) B (C) F (D) G (E) K
(B) B OBAFGKM (highest to lowest)
You see a reflecting telescope with a short, stubby tube and the eyepiece at the back. This telescope uses the (A) Newtonian Focus. (B) Cassegrain Focus. (C) Prime Focus. (D) Coudé Focus
(B) Cassegrain Focus.
Which of the following spectral types corresponds to the star with the lowest surface temperature? (A) K0 (B) K5 (C) G0 (D) G5
(B) K5
Our Sun is a G2V star with absolute magnitude 4.8. Suppose that a star of spectral type G2V is observed to have apparent magnitude 9.8. How far away is it? (A) 1 parsec. (B) 5 parsecs. (C) 10 parsecs. (D) 100 parsecs. (E) 1000 parsecs.
(D) 100 parsecs.
The frequency of a wave is defined to be (A) The distance from one crest to the next. (B) The number of crests that pass in one second. (C) The number of seconds that it takes for a crest to pass. (D) The distance from a maximum to a minimum. (E) The time for a set of crests to pass divided by the number of crests.
(B) The number of crests that pass in one second.
Which of these moons has landmarks that are not rotating with the rest of the moon, indicating a subsurface ocean? (A) Ganymede. (B) Titan. (C) Enceladus. (D) Europa.
(B) Titan.
The star Wemadeit shows a stellar parallax angle of 0.2 seconds of arc while the star Waytoofar shows a stellar parallax angle of 0.3 seconds of arc. From this, you can conclude that (A) Both stars are at the same distance from our Sun. (B) Waytoofar is closer to our Sun than Wemadeit. (C) Wemadeit is closer to our Sun than Waytoofar. (D) Waytoofar is moving faster than Wemadeit. (E) Wemadeit is moving faster than Waytoofar.
(B) Waytoofar is closer to our Sun than Wemadeit. (inversely)
In the Hertzsprung-Russell Diagram shown, which point represents a star of type F with absolute magnitude -5? (A) (B) (C) (D) (E)
(B) Yes. It is over the F and on the same horizontal line as -5.
The word 'Parallax' in the term 'Spectroscopic Parallax' is used because that term refers to (A) the use of stellar parallax. (B) a method for finding distances to stars. (C) a method for finding the masses of stars. (D) the use of parallel lines on the HR diagram.
(B) a method for finding distances to stars.
A mirror that is supposed to bring light from a star directly overhead to a focus must be shaped like (A) a flat surface. (B) a shallow bowl with the open part facing up. (C) an upside-down bowl with the open part facing down. (D) a shallow trough with the open part facing up. (E) an upside-down trough with the open part facing down.
(B) a shallow bowl with the open part facing up.
In a particular binary star system, we are only able to determine a minimum mass for each star and cannot determine the angle between our line of sight and the plane of the stars' orbits. This system is most likely (A) a visual binary system. (B) a spectroscopic binary system. (C) an eclipsing spectroscopic binary system.
(B) a spectroscopic binary system.
The main reason that telescope mirrors can be much larger than lenses is that the mirrors (A) can be made of metal. (B) are lighter because they are thinner. (C) are stronger because they are thicker. (D) can have holes in them.
(B) are lighter because they are thinner.
In a Hertsprung-Russell diagram, the brightest stars are found (A) at the bottom. (B) at the top. (C) on the right side. (D) on the left side.
(B) at the top.
In a Hertsprung-Russel diagram, Red Giant stars such as Betelgeuse are (A) at the upper left. (B) at the upper right. (C) at the lower left. (D) at the lower right.
(B) at the upper right.
A necessary (but probably not sufficient) condition for a planet to have active plate tectonics is that it (A) have an orbit in the habitable zone of its primary star. (B) be considerably larger than the planet Mars. (C) have carbon dioxide in its atmosphere. (D) have oxygen in its atmosphere.
(B) be considerably larger than the planet Mars.
Which of the following colors indicates the hottest star? (A) red. (B) blue. (C) yellow. (D) peach. (E) orange.
(B) blue.
A main-sequence star with less mass than our sun will be (A) hotter and brighter. (B) cooler and dimmer. (C) cooler and brighter. (D) hotter and dimmer.
(B) cooler and dimmer.
The one-wave turning angle of a telescope mirror determines its (A) light collection ability. (B) diffraction limit on its resolution. (C) atmospheric limit on its resolution. (D) chromatic aberration. (E) spherical aberration.
(B) diffraction limit on its resolution.
The primary mission of the Kepler Spacecraft is to (A) measure the distances to nearby stars. (B) find planets in orbit around nearby stars. (C) discover peculiar multiple star systems. (D) explore the interiors of nearby stars. (E) find nearby brown dwarf stars.
(B) find planets in orbit around nearby stars.
The range of distances of a planet from its primary star that will permit the existence of liquid water on the planet's surface is called the (A) water hole. (B) habitable zone. (C) inner system. (D) triple point.
(B) habitable zone.
In the Hertsprung Russel Diagram, a main sequence star might be found (A) in the upper right or lower left. (B) in the lower right or upper left. (C) in the center at the top or bottom. (D) halfway up at the right or left.
(B) in the lower right or upper left.
The range of signal frequencies between absorption bands caused by hydrogen and hydroxyl molecules (A) is always avoided by SETI programs because signals there are strongly absorbed. (B) is referred to as the "water hole" and is the frequency band that SETI programs usually choose. (C) is referred to as the "hydrogen band" and is usually avoided by SETI programs. (D) has no particular significance for SETI programs.
(B) is referred to as the "water hole" and is the frequency band that SETI programs usually choose.
The most energy-efficient way to send signals across interstellar distances is thought to be (A) laser light. (B) microwave radio. (C) Extreme low frequency (ELF) radiation. (D) TeraHertz radiation. (E) Gamma rays.
(B) microwave radio.
The reason that most SETI programs choose to listen at microwave radio frequencies is that (A) microwave receivers are easy to build. (B) microwaves are the most energy efficient way to send information. (C) microwaves can get through our atmosphere without being absorbed. (D) microwaves can be beamed in a single direction.
(B) microwaves are the most energy efficient way to send information.
The Earth's motion around the Sun causes (A) nearby stars to shift steadily in the same direction. (B) nearby stars to shift back and forth once a year. (C) all stars to jump randomly around. (D) all stars to move away from a point in the constellation Hercules.
(B) nearby stars to shift back and forth once a year.
The Viking Landers carried out several experiments on Martian surface soil. One of those experiments, the Pyrolytic Release Experiment gave a positive result for the presence of life forms. That result was interpreted to mean (A) that life might exist in Martian surface soil. (B) nothing because a sterilized control sample gave the same result. (C) nothing because it contradicted the results of the other experiments.
(B) nothing because a sterilized control sample gave the same result.
Here is the Drake Equation: N = R*×fp×ne×fl×fi×fc×L In this equation, N stands for the (A) expected lifetime of a communication-capable civilization. (B) number of communication-capable civilizations in our galaxy. (C) average number of habitable planets in a planetary system. (D) number of extraterrestrial messages that we might expect to detect in a year.
(B) number of communication-capable civilizations in our galaxy
A converging lens will send the light from a distant star through a point (A) on the same side of the lens as the star. (B) on the side of the lens opposite the star. (C) in the center of the lens. (D) at one edge of the lens. (E) infinitely far away from the lens.
(B) on the side of the lens opposite the star.
Planets that are in orbit around stars other than our own Sun are most often found by observing (A) telescope images of the planets. (B) small changes in starlight due to planetary transits. (C) small wobbles in our own Sun. (D) the microlensing of light from background stars.
(B) small changes in starlight due to planetary transits.
The Kepler Spacecraft is designed to measure (A) stellar parallaxes. (B) small changes in starlight from nearby stars. (C) the light emitted by extrasolar planets. (D) small wobbles in nearby stars. (E) the microlensing of light from distant stars.
(B) small changes in starlight from nearby stars.
The luminosity class of a star is determined by measuring (A) its brightness. (B) the broadening of spectral lines. (C) the positions of spectral lines. (D) the intensities of spectral lines.
(B) the broadening of spectral lines.
If we detect that the intensity of the light from a star is mostly constant but drops slightly to a new constant value for a while and then returns to its normal level and repeats this behavior at regular intervals, we can reasonably suspect that (A) a rogue planet is passing between us and the star. (B) the star has a planet in orbit around it. (C) the star is vibrating. (D) the star has a large dark spot on it.
(B) the star has a planet in orbit around it.
Because mirrors only use one surface, they have a big advantage over lenses: They can be (A) made more accurately. (B) thinner and larger in diameter. (C) thicker and stronger. (D) filled with more holes. (E) made out of metal.
(B) thinner and larger in diameter.
A mirror that is shaped like a shallow bowl sitting on the table with its open end facing up will focus light that comes (A) horizontally from the side. (B) vertically down from above. (C) vertically upward from below.
(B) vertically down from above.
A star at a distance of 1000pc should have an apparent brightness equal to its absolute brightness multiplied by (A) 10-2. (B) 10-3. (C) 10-4. (D) 10-5. (E) 10-6.
(C) 10-4.
Cruising far from the Sun, we notice that the Sun's apparent brightness has dimmed to 0.1 watts per square meter. We know that the apparent brightness at a distance of 1au is 1000 watts per square meter. How far from the Sun are we? (A) 1au (B) 10au (C) 100au (D) 1000au
(C) 100au
A star whose apparent brightness is 10-4 times that of a first magnitude star would have magnitude (A) 1. (B) 6. (C) 11. (D) 16. (E) 21.
(C) 11.
Suppose that a sound wave has a wavelength of 12 meters and a frequency of 100Hz. What is the speed of sound? (A) 12 m/s (B) 100 m/s (C) 1200 m/s (D) 0.012 m/s (E) 8.34 m/s
(C) 1200 m/s
The velocity of sound waves is roughly the same for all wavelengths. Suppose that a sound wave has a wavelength of one meter and a frequency of 1000Hz. The wavelength of a 500Hz sound wave would then be (A) 500 m. (B) 1000 m. (C) 2 m. (D) 1/2 m. (E) 1 m.
(C) 2 m.
Suppose that a sound wave has a wavelength of 2 meters and a frequency of 1000Hz. What is the speed of sound? (A) 2 m/s (B) 1000 m/s (C) 2000 m/s. (D) 500 m/s (E) .002 m/s
(C) 2000 m/s
The velocity of sound waves is roughly the same for all wavelengths. Suppose that a sound wave has a wavelength of one meter and a frequency of 1000Hz. The wavelength of a 250Hz sound wave would then be (A) 250 m. (B) 1000 m. (C) 4 m. (D) 1/4 m. (E) 1 m.
(C) 4 m.
The red line of a spectrum is normally at a wavelength of 656 nm. In the light of a star that is moving away from us, we might expect to see that red line at a wavelength of (A) 650nm. (B) 656nm. (C) 660nm.
(C) 660nm.
A multiple star system close to the Earth that is known to have stable orbits in the habitable zones of each of its stars is (A) Epsilon Aurigae. (B) Albireo. (C) Alpha Centauri. (D) Sirius. (E) Procyon.
(C) Alpha Centauri.
The closest star to Earth (other than the Sun) is part of a multiple star system called (A) Epsilon Aurigae. (B) Albireo. (C) Alpha Centauri. (D) Sirius. (E) Procyon.
(C) Alpha Centauri.
Which of these moons has geysers of water shooting out through cracks in the moon, indicating a subsurface ocean? (A) Ganymede. (B) Titan. (C) Enceladus. (D) Europa.
(C) Enceladus.
Which of the following spectral types corresponds to the star with the highest surface temperature? (A) K0 (B) K5 (C) G0 (D) G5
(C) G0
One requirement for a planet to support Earth-type life is that it be considerably larger than Mars. What is the reason for this requirement? (A) It is necessary for liquid water to exist on the planet's surface. (B) It is necessary for the planet to retain all of its carbon. (C) It is necessary for the planet to have active plate tectonics to close its carbon cycle. (D) It is necessary for the planet to retain oxygen in its atmosphere.
(C) It is necessary for the planet to have active plate tectonics to close its carbon cycle.
Which of the following statements best describes the presence of water on Mars? (A) Mars is completely without any form of water. (B) Mars has liquid water flowing steadily on its surface at the present time. (C) Mars has water frozen in its ice caps and may have liquid water below its surface. (D) Mars has never had liquid water on its surface.
(C) Mars has water frozen in its ice caps and may have liquid water below its surface.
The Viking Landers carried out several experiments on Martian surface soil. The final conclusion from those experiments was: (A) There are definitely microbes living in the soil of Mars. (B) No conclusion could be reached. (C) The surface of Mars is extremely hostile to all forms of organic matter.
(C) The surface of Mars is extremely hostile to all forms of organic matter.
Suppose that we find a few microbes living in the liquid water below the permafrost layer of Mars. Which of the following consequences of this discovery is most likely? (A) We learn something about the origin of life on Earth. (B) We get ideas for new treatments of disease. (C) We conclude that the universe is probably filled with life. (D) We conclude that life is extremely rare in the universe.
(C) We conclude that the universe is probably filled with life.
The star Wemadeit shows a stellar parallax angle of 0.4 seconds of arc while the star Waytoofar shows a stellar parallax angle of 0.3 seconds of arc. From this, you can conclude that (A) Both stars are at the same distance from our Sun. (B) Waytoofar is closer to our Sun than Wemadeit. (C) Wemadeit is closer to our Sun than Waytoofar. (D) Waytoofar is moving faster than Wemadeit. (E) Wemadeit is moving faster than Waytoofar.
(C) Wemadeit is closer to our Sun than Waytoofar.
We see what appears to be a single star. However, when the light from the star is put through a spectrometer, we see two distinct spectra, shifting back and forth. The star is actually (A) just a single star with a weird spectrum. (B) a visual binary system. (C) a double-line spectroscopic binary system. (D) a single-line spectroscopic binary system. (E) an astronometric binary system.
(C) a double-line spectroscopic binary system.
What astronomers refer to as a "standard candle" is defined as a light source whose (A) apparent magnitude is known. (B) distance is known. (C) absolute magnitude is known. (D) spectral type is known. (E) size is known.
(C) absolute magnitude is known.
In a particular binary star system, we are able to determine the masses and diameters of both stars This system is most likely (A) a visual binary system. (B) a spectroscopic binary system. (C) an eclipsing spectroscopic binary system
(C) an eclipsing spectroscopic binary system.
One difficulty with the microfossils that were found in the martian meteorite ALH84001 is that they (A) could not exist on Mars at the present time. (B) are the wrong shape to be living organisms. (C) are too small.
(C) are too small.
In a Hertsprung-Russel diagram,white dwarf stars such as Sirius B are (A) at the upper left. (B) at the upper right. (C) at the lower left. (D) at the lower right.
(C) at the lower left.
Adaptive optics is used to correct telescopes for (A) the diffraction limit. (B) chromatic aberration. (C) atmospheric turbulence. (D) spherical aberration. (E) poor light collection ability.
(C) atmospheric turbulence.
The Viking Landers carried out several experiments on Martian surface soil in order to detect the presence of life. Those same experiments were also carried out on a control sample of Martian surface soil that had been sterilized by heat. The purpose of doing experiments on the control sample was to (A) make sure the lander was working properly. (B) avoid getting a false negative result. (C) avoid getting a false positive result. (D) calibrate the landers' instruments.
(C) avoid getting a false positive result.
A star with an apparent magnitude of 5.7 and an absolute magnitude of -1.2 would appear in our sky as a star (A) of dazzling brightness. (B) of average naked-eye brightness. (C) barely visible to the naked eye. (D) visible only with a telescope.
(C) barely visible to the naked eye.
If we detect that a star is sometimes moving toward us and sometimes moving away and also find that this pattern repeats at regular intervals, we know for sure that the star (A) is part of a binary star system. (B) has at least one large planet. (C) has at least one object of unknown type orbiting around it. (D) is violating the Law of Inertia.
(C) has at least one object of unknown type orbiting around it.
The star Gliese 581 is of particular interest mainly because it is (A) only 20.4 light years away from the Earth. (B) known to have at least three planets. (C) known to have three terrestrial-size planets near or in its habitable zone. (D) a type M star with an extremely long lifetime and a rather small habitable zone.
(C) known to have three terrestrial-size planets near its habitable zone.
The main reason to suspect that Titan has a subsurface ocean of water is (A) patterns of cracks in the ice on its surface. (B) low fluxes of epithermal neutrons. (C) landmarks that are not rotating with the rest of the moon. (D) geysers of water shooting out through cracks in the moon.
(C) landmarks that are not rotating with the rest of the moon.
From the broadening of its spectral lines, one can determine a star's (A) spectral type. (B) apparent brightness. (C) luminosity class. (D) radial velocity.
(C) luminosity class.
Suppose that a star has a spectrum that includes red, blue, and violet lines spaced in the pattern of the lines from hydrogen but the violet lines are at 424nm and 400nm instead of the usual 434nm and 410nm. From this evidence, you can conclude that the star is (A) unusually hot. (B) unusually cold. (C) moving toward us. (D) moving away from us. (E) rotating.
(C) moving toward us.
One of the experiments carried out by the Viking Landers was to use a mass spectrometer to analyze the gas given off from a heated soil sample. The results of that experiment established that Martian soil contains (A) more carbon compounds than would be expected on a planet with a carbon-dioxide atmosphere. (B) just about the amount of carbon compounds that would be expected on a planet with a carbon-dioxide atmosphere. (C) no carbon compounds at all. (D) large organic hydrocarbons.
(C) no carbon compounds at all.
The habitable zone of a planetary system is defined to be the region where (A) large terrestrial planets might exist. (B) the intensity of light from the primary star is enough to support life. (C) planetary surfaces permit the existence of liquid water. (D) few asteroids can be found.
(C) planetary surfaces permit the existence of liquid water.
The difficult part of a SETI program is that you do not know what frequency band the extraterrestrials are using, so you need to listen to them all. The SERENDIP IV program, running on the Arecibo radio telescope, accomplishes this task by (A) turning the signal on each frequency into a text message and sending them to everyone in the United States for analysis. (B) using a large supercomputer to analyze the signal on each frequency in turn. (C) sending a batch of signals to each of several million home computers for analysis. (D) sending a batch of signals to each Xbox video game system for analysis.
(C) sending a batch of signals to each of several million home computers for analysis.
Planets that are in orbit around stars other than our own Sun are most often found by observing (A) telescope images of the planets. (B) small wobbles in our own Sun. (C) small wobbles in their primary stars. (D) small changes in pulsar emissions.
(C) small wobbles in their primary stars.
Spectroscopic parallax uses (A) annual position shifts of stars to calculate distance. (B) the doppler shift to find star velocities. (C) stellar spectra to locate stars in the HR diagram. (D) timing variations in brightness to estimate mass.
(C) stellar spectra to locate stars in the HR diagram.
The microfossils that were found in the martian meteorite ALH84001 are (A) regarded as proof that life once existed on Mars. (B) subject to continued argument because of doubts that the meteorite came from Mars. (C) subject to continued argument because of doubts that they are of biological origin. (D) regarded as disproven.
(C) subject to continued argument because of doubts that they are of biological origin.
The wavelength of a wave is defined to be (A) the number of waves passing in one second. (B) the distance from a crest to a trough. (C) the distance from one crest to the next. (D) the distance from one side of the wave to the other. (E) the maximum value of the quantity that is waving.
(C) the distance from one crest to the next.
The velocity of a wave is defined to be (A) the number of crests that pass divided by the time taken. (B) the distance from one crest to the next. (C) the distance traveled by a crest divided by the time taken. (D) the time taken for a crest to pass. (E) the number of crests that pass multiplied by the time taken.
(C) the distance traveled by a crest divided by the time taken.
For a visual binary star system, we can determine (A) only a minimum mass for each star. (B) only the mass of the smaller star in the system. (C) the masses of both stars in the system. (D) the diameters of both stars in the system. (E) the masses and diameters of both stars in the system.
(C) the masses of both stars in the system.
Stellar Parallax is caused by (A) the actual motion of stars relative to their neighbors. (B) the motion of our Sun relative to its neighbors. (C) the motion of the Earth around the Sun. (D) the finite speed of light. (E) turbulence in the Earth's atmosphere.
(C) the motion of the Earth around the Sun.
The focal point of a lens is (A) the place where it sends all light rays. (B) the center of curvature of the lens. (C) the place where it sends rays that are parallel to the axis. (D) the place where it sends rays that are off-axis. (E) the center of the lens.
(C) the place where it sends rays that are parallel to the axis.
In SETI programs, the "water hole" refers to (A) the range of signal frequencies that are not strongly absorbed or interfered with in our atmosphere and in interstellar space. (B) a quiet spot in the radio band that is caused by interactions with water molecules in interstellar space. (C) the range of signal frequencies between emissions caused by hydrogen and hydroxyl molecules.
(C) the range of signal frequencies between emissions caused by hydrogen and hydroxyl molecules.
The main difficulty with multiple star systems such as Alpha Centauri as places to look for life is that (A) they might not form planets at all. (B) the varying light intensity caused by the orbiting stars might mean that neither star has a stable habitable zone. (C) the shifting gravitational fields of the orbiting stars might mean that there are no stable orbits in their habitable zones.
(C) the shifting gravitational fields of the orbiting stars might mean that there are no stable orbits in their habitable zones.
The diffraction limit of a telescope refers to the effect of (A) atmospheric turbulence. (B) its light collection area. (C) the wavelength of light. (D) chromatic aberration. (E) errors in the lens shape.
(C) the wavelength of light.
The main reason that the SETI@home system needs to use the computing power of 5.2 million participating home computers is that (A) they think it is cool to use that many computers. (B) each computer does not do very much. (C) they are collecting and analyzing signals on millions of different radio channels. (D) they are performing highly sophisticated and time-consuming analyses of each individual signal.
(C) they are collecting and analyzing signals on millions of different radio channels.
The Alpha Centauri star system consists of (A) a single star. (B) two stars in orbit around each other. (C) two stars in close orbit around each other and a third star orbiting farther out. (D) three stars in close orbit around each other. (E) three stars in close orbit around each other and two stars orbiting farther out.
(C) two stars in close orbit around each other and a third star orbiting farther out.
Which of the following magnitudes corresponds to the brightest star? (A) +3.4. (B) +5.6. (C) +2.1. (D) -1.5. (E) +1.2
(D) -1.5. (negative = brighter)
The apparent brightness of our Sun is roughly 1000 watts per square meter. At a distance of 30 times the Earth-Sun distance, the apparent brightness of our Sun would be (A) 30000 watts per square meter. (B) 33 watts per square meter. (C) 900,000 watts per square meter. (D) 1.1 watts per square meter. (E) 1000 watts per square meter.
(D) 1.1 watts per square meter.
A star is found to have absolute magnitude 4 and apparent magnitude 19. How far away is it? (A) 10 parsecs. (B) 15 parsecs. (C) 150 parsecs. (D) 10,000 parsecs. (E) 100,000 parsecs.
(D) 10,000 parsecs.
Suppose that the color and behavior of a star identify it as a type that we know has absolute magnitude 4.8. If the star's apparent magnitude is found to be 9.8, how far away is it? (A) 5 parsecs. (B) 10 parsecs. (C) 50 parsecs. (D) 100 parsecs. (E) 1000 parsecs.
(D) 100 parsecs.
Suppose that a flash of lightning from a cloud 2500 meters away is followed by a clap of thunder two seconds later. Assume that the light arrived in a negligible time and calculate the speed of the sound waves. (A) 2500m/s (B) 2m/s (C) 5000m/s (D) 1250m/s (E) 1000m/s
(D) 1250m/s
A star whose apparent brightness is 10-6 times that of a first magnitude star would have magnitude (A) 1. (B) 6. (C) 11. (D) 16. (E) 21.
(D) 16.
The star alpha-Centauri C has moved across the sky by 3853 seconds of arc during the last thousand years - slightly more than one full degree of arc. Its proper motion is (A) 3853"/yr. (B) 38.53"/yr. (C) 0.26"/yr. (D) 3.853"/yr. (E) 1.9265"/yr.
(D) 3.853"/yr. (3853/1000)
The star Kruger 60 shows a heliocentric stellar parallax of almost exactly 0.25 seconds of arc. The distance from our Sun to Kruger 60 is (A) 0.25 parsecs. (B) 0.75 parsecs. (C) 2 parsecs. (D) 4 parsecs. (E) 8 parsecs.
(D) 4 parsecs. (1/.25) = 4
In the Hertsprung-Russel diagram shown, point number 4 could be a
(D) B0 star of absolute magnitude 10.
Which of the following spectral types corresponds to a star on the main sequence? (A) K2III (B) G2IV (C) A2Ib (D) B4V (E) O2Ia
(D) B4V
Which of these answers describes the fundamental assumption that is behind all of the methods that astronomers refer to as the "distance ladder?" (A) It is possible to calculate the absolute magnitudes of nearby objects. (B) It is possible to measure the apparent magnitudes of distant objects. (C) Nearby objects show close relationships between absolute magnitude and spectral type. (D) Distant objects are similar to nearby objects.
(D) Distant objects are similar to nearby objects.
Which of these moons has patterns of cracks in the ice on its surface. indicating a subsurface ocean? (A) Ganymede. (B) Titan. (C) Enceladus. (D) Europa.
(D) Europa.
In the Hertzsprung-Russell Diagram shown, which point represents a star of type B with absolute magnitude +10? (A) (B) (C) (D) (E)
(D) Yes. That is over the B and on the same line as +10.
A star whose full spectral type is K2V is (A) a red supergiant star. (B) a red giant star. (C) a red subgiant star. (D) a red main sequence star. (E) a bright blue supergiant star.
(D) a red main sequence star. (V puts it in the main sequence)
We see what appears to be a single star. However, when the light from the star is put through a spectrometer, we see that its spectrum is shifting back and forth. The star is most likely (A) just a single star with a weird spectrum. (B) a visual binary system. (C) a double-line spectroscopic binary system. (D) a single-line spectroscopic binary system. (E) an astronometric binary system.
(D) a single-line spectroscopic binary system.
The main reason to suspect that Enceladus has a subsurface ocean of water is (A) patterns of cracks in the ice on its surface. (B) low fluxes of epithermal neutrons. (C) landmarks that are not rotating with the rest of the moon. (D) geysers of water shooting out through cracks in the moon.
(D) geysers of water shooting out through cracks in the moon.
Suppose that a star has a spectrum that includes red, blue, and violet lines spaced in the pattern of the lines from hydrogen but the violet lines are at 444nm and 420nm instead of the usual 434nm and 410nm. From this evidence, you can conclude that the star is (A) unusually hot. (B) unusually cold. (C) moving toward us. (D) moving away from us. (E) rotating.
(D) moving away from us.
In a Hertsprung-Russell diagram, the hottest stars are found (A) at the bottom. (B) at the top. (C) on the right side. (D) on the left side.
(D) on the left side.
Consider a light source whose absolute magnitude can be deduced from the properties of the light that reaches us from that source. Astronomers often refer to this sort of object as a (A) reference object. (B) distance marker. (C) spectroscopic standard. (D) standard candle. (E) brightness reference.
(D) standard candle.
A star is observed to have an apparent brightness which is 10-6 times its absolute brightness. How far away is it? (A) 106 parsecs. (B) 10 parsecs. (C) 100 parsecs. (D) 1000 parsecs. (E) 10,000 parsecs.
(E) 10,000 parsecs.
A star is found to have absolute magnitude 4 and apparent magnitude 24. How far away is it? (A) 10 parsecs. (B) 20 parsecs. (C) 200 parsecs. (D) 10,000 parsecs. (E) 100,000 parsecs.
(E) 100,000 parsecs.
You hear a 1000Hz tone from a radio that is 20 feet away from you and listen for 4 seconds. How many pressure maxima pass by your ear? (A) 100. (B) 50. (C) 250. (D) 5000. (E) 4000.
(E) 4000.
You hear a 1000Hz tone from a radio that is 10 feet away from you and listen for 5 seconds. How many pressure maxima pass by your ear? (A) 100. (B) 5. (C) 10. (D) 200. (E) 5000.
(E) 5000
Of all the things that might go wrong with distances found by using the method that astronomers refer to as the "distance ladder," which of these is the one that an astronomer would say is most likely? (A) The parallax-distance formula is incorrect. (B) The distance-distance modulus formula is incorrect. (C) The parallaxes of nearby objects have been measured incorrectly. (D) The apparent magnitudes of distant objects have been measured incorrectly. (E) Distant objects are not behaving the same as nearby objects.
(E) Distant objects are not behaving the same as nearby objects.
In the Hertsprung-Russel diagram shown, point number 3 could be a (A) K2 star of absolute magnitude 10. (B) B0 star of absolute magnitude -5. (C) F0 star of absolute magnitude -5. (D) B0 star of absolute magnitude 10. (E) F9 star of absolute magnitude 5.
(E) F9 star of absolute magnitude 5.
Which of the following spectral classes corresponds to the lowest surface temperature (on this list)? (A) A (B) B (C) F (D) G (E) K
(E) K OBAFGKM (highest to lowest)
A star of spectral type O should look (A) red. (B) orange. (C) yellow. (D) white. (E) blue.
(E) blue.
The problem of stars "twinkling" due to atmospheric turbulence (A) cannot be corrected. (B) can only be corrected by putting telescopes in space. (C) can be corrected by going to larger telescope mirrors.. (D) can be corrected by using a more powerful eyepiece. (E) can be corrected by using a guide star.
(E) can be corrected by using a guide star.
For a spectroscopic binary star system, we can determine (A) only the mass of the smaller star in the system. (B) the masses of both stars in the system. (C) the diameters of both stars in the system. (D) the masses and diameters of both stars in the system. (E) only a minimum mass for each star.
(E) only a minimum mass for each star.
For an eclipsing spectroscopic binary star system, we can determine (A) only a minimum mass for each star. (B) only the mass of the smaller star in the system. (C) the masses of both stars in the system. (D) the diameters of both stars in the system. (E) the masses and diameters of both stars in the system.
(E) the masses and diameters of both stars in the system.
Which of the following pictures is the most like the main sequence on a Hertsprung-Russel Diagram? (A) (B) (C) (D) (look at the picture)
A) Yes. Steepest at the ends and going from lower right to upper left.