Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
65 Cards in this Set
- Front
- Back
|
T/F Earth orbits the sun at an average distance of 1 AU
|
TRUE
|
|
|
From the northern hemisphere, the north star is lower in the sky in winter T/F
|
False
|
|
|
T/F In a scale model of the solar system where the sun is the size of a grapefruit, it would take several minutes to walk from sun to pluto
|
TRUe
|
|
|
T/F Over the course of the year, the moon can be seen in our nighttime about half the time
|
True
|
|
|
The geocentric model was useless for predicting planetary positions T/F
|
False
|
|
|
If you lived on the moon you'd see 'full earth' when we see new moon T/F
|
True
|
|
|
Which of the following significantly influences our view of stars in the night sky from Earth? (assume rates, sizes, and distances that are “within reason” for planets)
a. Earth’s rotation b. Earth’s size c. Earth’s distance from the Sun d. Earth’s orbital motion e. Both a and d |
E
|
|
|
9. On the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, when did life arise on Earth?
a. April b. Late September c. Mid December d. Several hours ago e. Several seconds ago |
B
|
|
|
Suppose Earth rotated on its axis ‘the other direction’. Which of the following would be true?
a. Circumpolar stars would circle in reverse b. Horoscopes would list the signs of the zodiac in reverse order c. Polaris would lie above the South Pole d. aandc |
A
|
|
|
You see a star about 25° west of your meridian and 50° above your southern horizon in Boulder.
If you were to look at the star again in two hours, where would you find it? a. At your zenith b. East of your meridian c. On your meridian d. Further west of your meridian e. Below your eastern horizon |
D
|
|
|
Why are the Sun, Moon and planets seen only in the constellations of the zodiac?
a. Earth’s celestial equator defines the zodiac, and we view the Moon and planets from Earth b. the constellations in the zodiac are the oldest, and the planets have been known from ancient times c. the planets all orbit the Sun in nearly the same plane, and the zodiacal constellations are in that plane d. the planets all revolve in the same direction around the Sun e. none of the above |
C
|
|
|
The tilt of Mars is currently ~25°. However, the tilt varies over millions of years between 0° and 60°. During times when the tilt of Mars is 60°, how are the seasons different from today?
a. They don’t last as long. b. They are less extreme. c. They aren’t. d. They are more extreme. |
D
|
|
|
Why are different stars seen at night during different seasons?
a. because as Earth orbits the Sun, the Sun obscures our view of different constellations b. because of precession c. because of Earth’s axis tilt d. because stars move during the year |
A
|
|
|
if there is going to be a total solar eclipse today then you know that
a. The Moon is unusually close to Earth b. The Moon’s phase is new c. The Moon’s phase is full d. It is ‘crazy time’ (i.e. there are no solar eclipses during the day) |
B
|
|
|
Jupiter’s 4 large moons (Io, Europa, Ganymede, and Callisto) all have one side always facing Jupiter. This means that...
a. ...the moons do not rotate (spin). b. ...each moon has a spin period equal to its orbit period. c. ...Jupiter has a spin period equal to the moons’ orbital period. d. ...the moons have a spin period equal to Jupiter’s spin period. e. ...Jupiter and the moons all orbit the Sun at the same rate. |
B
|
|
|
Which of the following statements about the geocentric (Ptolemaic) model is least accurate?
a. Stellar parallax could not be observed by astronomers working hundreds and thousands of years ago, consistent with a stationary Earth. b. Ptolemy’s model used ‘circles upon circles’ (epicycles) to explain apparent retrograde motion of planets. c. Sun-centered models did not work much better than geocentric models until the true shape of planetary orbits was revealed. d. Copernicus proposed the first Sun-centered model, with all planets having circular orbits. |
D
|
|
|
Primitive cultures used astronomical observations to do all of the following except:
a. determine the shape of planetary orbits. b. decide when to plant crops. c. navigate. d. predict eclipses. e. predict the position of the sun in the sky at certain times of year. |
A
|
|
|
A planet is detected orbiting a star with the same mass as our Sun. The period of the planet can be detected based on the wobble of the star. The planet’s period is 9 months.
a. The planet has average orbital distance of 1 AU b. The planet has average orbital distance of more than 1 AU c. The planet has average orbital distance of less than 1 AU d. We can’t tell how far the planet is from the star. Kepler’s laws only work for our Sun. |
C
|
|
|
Why aren’t there eclipses approximately every two weeks?
|
The Moon’s orbital plane is tilted with respect to the ecliptic. Therefore we can only have eclipses when the Moon passes through the ecliptic in a position where it is lined up with the Earth and Sun. This only happens during two times of year.
|
|
|
Why it is more difficult, using the stars, to determine your longitude than it is to determine your latitude?
|
Latitude can easily be determined from any location by finding the altitude of the north (or south) celestial pole in your local sky. Longitude is much more challenging because observers at the same latitude (but different longitude) see the same stars over the course of a night, at the same positions. Thus we can’t use the position or path of stars in the sky to tell us longitude.
|
|
|
Why do we credit Galileo with ‘sealing the case’ for a Sun-centered solar system?
|
Galileo made telescope observations that removed all reasonable objections to the Earth-centered solar system. For example, he observed moons orbiting Jupiter, indicating that Earth was not ‘special’. Also, he observed the phases of Venus, which were consistent with an Sun-centered solar system but inconsistent with an Earth-centered solar system.
|
|
|
Why do planets exhibit apparent retrograde motion?
|
Because planets and Earth both go around the Sun. As Earth ‘catches up to’ and ‘passes’ a planet it appears to slow down and turn around in our sky, relative to the background stars.
|
|
|
The kinetic energy of any moving object must be conserved T/F
|
False
|
|
|
Astronauts in the space station feel weightless because the gravitational force that Earth exerts on them is much smaller than on Earth’s surface. T/F
|
false
|
|
|
Any solid object in our solar system with a moon will, given enough time, eventually change its rotation rate so that it always keeps the same face toward the moon. T/F
|
True
|
|
|
the number of planets with rings equals the number of planets without rings. T/F
|
True
|
|
|
Given unlimited time, Venus (and the other planets) would eventually spiral into the Sun.
T/F |
False
|
|
|
Some small asteroids and comets may have been ejected from the solar system as it formed.
T/F |
True
|
|
|
Some of the outer planets may have ‘switched places’ (in terms of distance from the Sun) after forming.
T/F |
True
|
|
|
Suppose you are in an elevator that is moving downward. As the elevator nears the ground floor, it slows down. While the elevator moves downward with decreasing speed, your weight will be:
a. Greater than your normal weight at rest b. Equal to your normal weight at rest c. Less than your normal weight at rest d. Exactly zero e. Conserved |
A
|
|
|
You are an astronaut taking a spacewalk to fix a spacecraft with a 3 million dollar hammer. Your lifeline breaks and the jets on your backpack are out of fuel. To return safely to the spacecraft you should:
a. Start yourself spinning, giving yourself enough angular momentum to reach the ship b. Throw the hammer away from the ship c. Use a swimming motion with your arms d. Kiss your ship goodbye e. Throw the hammer toward the ship |
B
|
|
|
A white ball hits a yellow ball on a pool table and remains motionless. The white ball has double the mass of the yellow ball. What happens to the yellow ball?.
A. It moves faster than the ball that hit it – since momentum is conserved and the yellow ball has smaller mass, it must have higher velocity b. It moves faster than the ball that hit it – since the white ball stopped spinning it gave its angular momentum to the yellow ball c. It moves the same speed as the ball that hit it – the total speed in the system is conserved d. It moves slower than the ball that hit it – since momentum is conserved and the yellow ball has lower mass, it must have lower velocity e. It moves slower than the ball that hit it – the less massive yellow ball must spin more slowly to conserve angular momentum |
A
|
|
|
Planets travel in Keplerian orbits around the Sun. What can we say about their motion?
a. Their speed changes, but their velocity does not b. They are always accelerating c. They are in freefall ‘around’ the Sun d. Some force is acting on the planets e. b,c,andd |
E
|
|
|
Replacing an orbiting object with one having triple the mass would triple all of the following except:
a. its orbital velocity b. the gravitational force it experiences as it orbits c. its orbital angular momentum d. its momentum e. its kinetic energy |
A
|
|
|
Which of the following is not an observed pattern of motion in our solar system?
a. Most planets rotate in the same direction in which they orbit b. All planets orbit the Sun in the same direction c. Most planetary orbits lie nearly in the same plane d. Almost all large moons orbit their planet in the same direction as the planet’s rotation e. Most planets orbit at the same speed |
E
|
|
|
Why do all planets in our solar system orbit in nearly the same plane?
a. The interstellar cloud from which the solar nebula formed was originally somewhat flat. b. The force of gravity pulled gas and dust that would eventually form planets downward into a flat disk. c. As the solar nebula cooled, the gas and dust that would eventually form planets settled onto a disk. d. Planets formed from a disk of material that flattened as a natural consequence of collisions between particles, changing random motions into more orderly ones. e. Jupiter and the Sun pulled them in line. |
D
|
|
|
How do asteroids differ from comets?
a. Asteroids are rocky bodies and are less dense than the comets, which are made of icy material b. Asteroids and comets are both made of rocky and icy material, but asteroids are smaller in size than comets c. Asteroids are rocky bodies and are denser than the comets, which are made of icy material d. Asteroids are made of icy material and are denser than the comets, which are more rocky e. Asteroids are made of icy material and are less dense than the comets, which are rockier |
C
|
|
|
Which of the following observations would be inconsistent with our current theory of solar system formation?
a. We discover a small new moon of Jupiter orbiting clockwise as viewed from above b. We discover another stellar system with 4 planets, two jovian planets close to the star and two rocky planets far from the star c. We discover an icy dwarf planet beyond the orbit of Pluto with an orbit that keeps it outside of the orbit of Neptune and is in the same plane as the jovian planets d. We discover a previously unknown small comet passing through the inner solar system e. Bothbandc |
B
|
|
|
Which of the following is not an example of comparative planetology in action?
a. Voyager measurements of planetary magnetic fields in the outer solar system b. A theory of the development of a greenhouse atmosphere on early Mars c. A computer model of volcanic eruptions on Mars and Io d. A study of weather on terrestrial planets e. A search for water near the poles of Mercury and the Moon |
B
|
|
|
Why are there relatively few comets with average orbital distance between the orbits of Jupiter and Neptune?
|
Because comets that formed in that location were scattered away through gravitational interactions with the jovian planets. These objects are now in the Oort cloud.
|
|
|
Explain how conservation of angular momentum is consistent with Kepler’s 2nd Law (that tells us that the velocity of an object orbiting the Sun is greater when the object is closer to the Sun)
|
Angular momentum is mass × velocity × distance from spin/orbit axis. When a planet is far from the Sun, the distance is large, and when it is close to the Sun the distance is small. To conserve angular momentum, the velocity of the planet must therefore be large when the planet is close to the Sun and small when it is far away.
|
|
|
Describe what is happening to cause the length of Earth’s day to slowly increase over time.
|
The Moon raises tidal bulges on Earth, which ‘race ahead’ of the Earth-Moon line because of Earth’s rotation. The Moon ‘pulls’ on these bulges gravitationally, trying to bring them back in line. Earth’s rotation slows as a result.
|
|
|
According to the leading hypothesis, how did the Moon form? Give at least one piece of evidence that supports this hypothesis.
|
The Moon formed as the result of a giant impact of a planetesimal with Earth. Several lines of evidence support this hypothesis, including the Moon’s low density (similar to Earth’s outer layers), its composition (similar to Earth’s outer layers), and the relative absence of volatile materials (things that easily exist in gaseous form).
|
|
|
Air in a typical working oven has a temperature at least 100° higher than boiling water. Why would the boiling water hurt your hand, but not the air in the oven? Use the term thermal energy for full credit.
|
Temperature is a measure of average kinetic energy. But there are more atoms and molecules in the boiling water than in the air of the oven, so the water has more thermal energy, which is the total kinetic energy of the atoms and molecules. This larger thermal energy is what hurts your hand – there are more collisions of fast moving particles with your hand in the water.
|
|
|
Earth outgassed as much carbon dioxide as Venus, but on Earth it is locked up in the oceans and rocks.
T/F |
True
|
|
|
impacts (from comets and asteroids) are both a source and loss process for planetary atmospheres.
T/F |
True
|
|
|
Erosion is the most important geologic process on venus. T/F
|
False
|
|
|
Spectral lines for a particular element appear at the same wavelength in both emission and absorprtion line spectra. T/F
|
True
|
|
|
Smaller worlds generally have thinner lithospheres relative to the size of the planet. T/F
|
False
|
|
|
The main process by which heat is transported through Earth’s mantle is
a. convection b. differentiation c. conduction d. radiation e. accretion |
A
|
|
|
How did the lunar maria form?
a. The maria are the result of gradual erosion by micrometeorites striking the moon b. The giant impact that created the Moon left smooth areas that we call the maria c. Gases escaping from the Moon’s interior heated and eroded the surface in the regions of the maria d. The early bombardment created heat that melted the lunar surface in the regions of the maria e. Large impacts fractured the Moon’s lithosphere, allowing lava to later fill the impact basins |
E
|
|
|
Suppose that you find a rock that contains some brainium-1000 (half-life of ~10 million years). You measure the amount and determine that there are 10 grams of branium-1000 in the rock. You also measure 70 grams of its decay product (nevinium-1000) in the rock. How old is the rock?
a. 10 million years b. 20 million years c. 30 million years d. 40 million years e. 80 million years |
C
|
|
|
When we see a sparsely cratered region of a planetary surface, we infer that
a. the surface in the region is younger than the surface in more heavily cratered regions b. the planet is rotating very slowly and only one side was hit by impactors c. the planet formed after the age of bombardment and missed out on getting hit by leftover planetesimals d. there is little volcanic activity to create craters e. the surface in the region is older than the surface in more heavily cratered regions |
A
|
|
|
Which of the following planets have tectonic features apparent on their surface today?
a. Mars b. Earth c. V enus d. Mercury e. All of the above |
E
|
|
|
Telescopes are just now becoming capable of taking images of planets orbiting other stars, and can already measure their spectra in some cases. What should we be able to learn about these planets in the coming years, assuming sufficiently precise observations?
a. The chemical elements in their atmospheres b. Their temperature c. Their motion toward or away from us d. Their rotation speed e. All of the above |
E
|
|
|
Blue light has about double the frequency of red light. How do the wavelength and energy of blue light compare to those of red light?
a. Blue light has half the energy and half the wavelength of red light. b. Blue light has double the energy and double the wavelength of red light. c. Blue light has double the energy and half the wavelength of red light d. Blue light has half the energy and double the wavelength of red light. |
C
|
|
|
Suppose we halved Earth’s surface pressure but kept the total fraction of greenhouse gases unchanged. What would happen to Earth’s surface temperature? (ignore any albedo changes)
a. It would increase b. It would decrease c. It would stay the same d. It can’t be predicted based solely on this information |
B
|
|
|
From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 486.1 nanometers. The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 485.9 nanometers. What can we conclude?
a. The hydrogen in the star is colder than the hydrogen measured in the lab b. The hydrogen in the star is hotter than the hydrogen measured in the lab c. The star is moving toward us d. The star is moving away from us e. Bothaandd |
C
|
|
|
Which of the following factors could explain a gradual warming trend in a planet's climate?
a. A decrease in the brightness of the Sun b. A decreasing albedo c. A decrease in the amount of greenhouse gases in the atmosphere d. A major volcanic eruption that increases the albedo of the planet by making clouds e. None of the above |
B
|
|
|
Venus may have started with an ocean’s worth of water. Where is it now?
a. Changed to atmospheric carbon dioxide through chemical reactions b. In the atmosphere, vaporized from the intense heat caused by the greenhouse effect c. Combined with surface rocks in chemical reactions d. Lost when ultraviolet sunlight broke apart the water molecules and the hydrogen escaped to space e. Frozen beneath the surface |
D
|
|
|
Which of the following atmospheric species on Earth doesn’t come primarily from outgassing?
a. sulfur dioxide b. oxygen c. carbon dioxide d. water e. nitrogen |
B
|
|
|
Describe a feedback process for clouds, and identify it as positive or negative feedback.
|
_positive_ feedback: The amount of clouds in the atmosphere decreases. As a result ... less IR radiation is trapped near the surface, cooling it. The cooler surface promotes condensation of water in the atmosphere to the surface. With less water in the atmosphere, the amount of clouds in the atmosphere decreases.
|
|
|
How does differentiation provide heat for planetary interiors? Does it provide significant heat for the terrestrial planets today?
|
Differentiation occurs when dense (massive) material sinks relative to less dense (light) material. The dense material loses gravitational potential energy, and because total energy is conserved the amount of thermal energy in the interior increases. Differentiation occurred early in solar system history, and the energy it provided is not significant today.
|
|
|
Why does Earth have a stratosphere, and how do gases there interact with light from the Sun?
|
Earth has a stratosphere because ozone (produced from oxygen supplied to the atmosphere by life) absorbs ultraviolet light from the Sun. This absorbed energy leads to warming in the middle of what we call he ‘stratosphere’.
|
|
|
Suppose you take a pure red object into a completely dark room and shine pure blue light on it. What color would the object have? Support your answer.
|
A pure red object absorbs all colors but red. Therefore, any blue light that strikes the object will be absorbed. In a dark room you would not be able to see the ball at all (it would be black) if the only source of light is blue.
|
