ASTRONOMY FINAL
How does Valles Marineris (valley on mars) differ from the Grand Canyon?
-It is larger. -It is steeper. -It was not made by water.
How have astronomers detected exoplanets?
-Measuring the Doppler shift of the light from a star to see how the star "wobbles" due to the gravity of the planet -Directly observing the exoplanet around its parent star -Observing the transit(when it goes in front) of an exoplanet across its star by measuring the decrease in light received from the star
Saturn's rings show signs of being an active and dynamic system, with many features changing on short timescales. Scientists believe that the rings are quite young. If the rings are indeed so young, then either they are the result of a relatively recent, possibly catastrophic event in the planet's system, or they are replenished from time to time. Select the statements that could explain how Saturn's rings were created or are replenished.
-Medium-sized moons are torn apart as they pass into Saturn's Roche limit. -A collision occurs between two moons near the Roche limit, shattering both. -Meteoritic impacts chip off debris from the moons just outside the Roche limit. -A large comet collides with a moon near the Roche limit, breaking apart the moon.
It is thought that Mars used to have running water on the surface. Which of the following are necessary consequences of that idea?
-The atmosphere used to be thicker. -The temperature used to be warmer.
Jupiter's differential rotation and complex atmospheric structure induce turbulent storms, such as the Great Red Spot. Identify the statements that correctly describe the characteristics of storm systems on Jupiter.
-The larger the storm, the longer it can last. -Individual storm systems can interact, resulting in the storm growing or fading out. -Storms are localized features, confined and powered by zonal flow.
What properties can be inferred from radial velocity measurements?
-an exoplanet's mass -an exoplanet's orbital period -an exoplanet's semi-major axis
Choose the correct properties of some exoplanets that challenged the theories of planetary formation based on the solar system.
-beeing gas giants and locating very close to their stars -having very eccentric orbits
What are some consequences of Jupiter's enormous magnetic field?
-large aurorae displays at the planet's poles -powerful versions of Earth's van Allen Belts -extremely strong radio emission
What measurements are required to estimate the bulk density of an exoplanet?
-mass -radius/diameter
Which of the following are found on the surface of Mercury?
Craters and scarps
A moon placed at a planet's Roche limit will
break into smaller pieces.
How do we know what the surface of Venus looks like?
by bouncing radio waves off its surface
What is the primary component of the atmosphere of Jupiter?
hydrogen
The main constituent of Jupiter's atmosphere is
hydrogen.
A successful scientific model of the origin of planetary systems must account for all of the following solar system features, except for
intelligent life.
Venus's atmosphere
is composed mostly of carbon dioxide.
Io's surface appears very smooth because it
is continually resurfaced by volcanic activity.
Compared with the Earth's orbit, the orbit of Mars
is more eccentric.
Venus is never seen at midnight because
it is closer to the Sun than is Earth.
What intrinsic property of Venus makes it very reflective of light?
its clouds
In appearance, what immediately distinguishes Saturn from all the other planets?
its large ring system
Jupiter's rocky core is
larger than Earth.
Saturn's rings look bright because __________.
light from the Sun reflects off the material in the rings
The moon of Jupiter most similar in size to Earth's Moon is
lo
Saturn's rings are composed of __________.
lots of individual particles of ice and rock
Which region of Jupiter generates its magnetic field?
metallic hydrogen layer
In 1781, Uranus was the first new planet to be discovered in how many years?
more than 2000
How does the mass of Jupiter compare to the mass of all the other planets combined?
more than twice as much
Compared with Earth's density, the density of Jupiter is
much less.
We have found all of the following kinds of exoplanets EXCEPT ____________.
objects indentical to Earth
What keeps the surface of Venus looking so young?
ongoing volcanism
Venus's surface is permanently obscured by clouds. As a result, the surface has been studied primarily by
orbiting satellites using radar.
The lengths of the seasons on Mars can be determined by observing the planet's
polar caps.
Jupiter is noticeably oblate (flattened) rather than spherical primarily because of which of the following physical effects?
rapid rotation
In comparison to the atmosphere of Venus, the vastly different atmospheric character of Mars is likely due to a/an
reverse greenhouse effect.
Which of the following provides evidence that water once flowed on Mars?
runoff and outflow channels
Compared with the time it takes Jupiter to orbit the Sun once, the time it takes Saturn, which is twice as far away, to orbit the Sun is
significantly more than twice as long.
Compared with Earth's diameter, the diameter of Mars is
significantly smaller.
Which of the following best describes Venus's rotation?
slow and retrograde(EW)
Compared with Earth's atmosphere, most of Venus's atmosphere is
spread out much farther from the surface.
The extreme seasonal variations on Uranus over the course of a complete orbit around the Sun are due to which of the following?
the 98° tilt of its rotation axis to its orbital plane
Uranus was discovered about the same time as
the U.S. Declaration of Independence.
What do the different colors in Jupiter's clouds indicate?
the depth at which the clouds reside within its atmosphere
The Galilean moons of Jupiter are sometimes described as a miniature inner solar system because
the moons' densities decrease with increasing distance from Jupiter.
The discovery of new planets mostly requires
the patient use of improving technology.
What two factors enable Saturn to retain its primordial hydrogen?
the planet's large mass (which means the minimum speed that gases can escape the atmosphere is a large number) and low temperature
The discovery of a moon orbiting a planet allows astronomers to measure
the planet's mass.
Which of the following properties can be inferred from the star's orbital period?
the planet's orbital radius
What is a habitable zone?
the region around a star where liquid water can exist on or near a planetary surface
The Roche limit is that distance from a planet where ________.
tidal forces are equal to internal forces
What is the source of Io's volcanic activity?
tidal heating
The deeper you dive into the atmospheres of the outer planets, the higher the temperature.
true
The surface of Mars shows which of the following principal characteristics?
two distinctly different regions with different cratering records and histories
Saturn's moon Iapetus has a surface that shows which of the following features?
two-tone markings
What occurs during southern summer on Mars?
very large dust storms
Compared with Earth, Venus has a level of plate tectonic activity that is
virtually nonexistent.
Saturn's rings are composed of mainly which of the following?
water ice
Saturn's cloud layers are much thicker than those of Jupiter because Saturn has
weaker surface gravity.
Would you expect Mars to experience seasons as Earth does? Why or why not?
yes, because its rotation axis is tilted relative to its orbital axis
Is it possible to determine the planet's mass from the star's velocity curve?
yes, by measuring both the star's orbital period and its change in velocity over the orbit
What properties of exoplanets can be inferred from planetary transit(when it passes in front of its sun) measurements?
It's semi-major axis, diameter/radius, mass, and orbital period
Why is Saturn's atmosphere less varied in color and appearance than Jupiter's atmosphere?
Its top clouds are thicker, with few holes and gaps, and they obscure the deeper layers.
How was the issue of gas giant planets locating very close to their stars resolved?
It has been proposed that these "hot Jupiters" form far from their stars, but gravitationally interacted with other planets and were forced to "migrate" inward.
How was the issue of planets having very eccentric orbits resolved?
It has been proposed that these eccentric orbits result from gravitational interaction with other planets.
What impact has the greenhouse effect had on the surface environment of Venus?
It has raised the surface temperature by hundreds of degrees.
Which of the following statements about the planetary feature known as Olympus Mons is true?
It is a volcanic peak on Mars nearly as big across as Texas.
Which of the following statements about the inner core of Jupiter is true?
It is large compared to the size of Earth, and it is rocky.
Why is Saturn's atmosphere almost three times thicker than Jupiter's?
It is less massive than Jupiter; its gravity is weaker.
How do we know that the southern hemisphere of Mars is older than the northern hemisphere?
It is more heavily cratered.
Which of the following features on Mars is/are volcanic in origin?
Alba Mons
What is a super-Earth?
An exoplanet with a mass of around 2-10 times the mass of Earth.
Why are the moons of Uranus and Neptune so dark?
They are subject to radiation darkening.
All but one of the following properties of Uranus's rings makes them different from the rings of Saturn. Which property is the same for both planets?
They are very thin.
If transits(when it passes in front of its sun) are so rare, why do astronomers think they are the best way to search for exoEarths?
They can yield more accurate information about the planet's mass, radius, and orbital period.
Mars and Earth are similar in many ways and different in others. Which of the following is one of the ways in which they are different?
They have different densities.
What does the density of the moons of Mars tell us?
They may be remnants from the earliest stages of solar system formation.
How do astronomers determine the "wobble" of a star with an exoplanet?
They measure the Doppler shift of its light as it moves toward and away from us.
Why weren't the outermost planets discovered until after the invention of the telescope?
They were too faint to be observed with the unaided eye.
The solar system object most similar to Neptune is
Uranus
Which planet has the greatest tilt of its rotation axis?
Uranus
Why do Uranus and Neptune have such coloration? Choose the correct explanation.
Uranus and Neptune have a larger abundance of methane in their surface clouds compared to Jupiter or Saturn. The methane absorbs red light very efficiently. Therefore, the reflected sunlight we receive from Uranus and Neptune contains less red light and is mostly blue.
According to the standard model of planetary system formation, which of the facts below is an example of an irregularity?
Uranus has an extremely tilted rotation axis.
Mercury
-1st planet from the Sun -dark grey -terrestrial -no moons -has craters and scarps(steep banks or slopes) -small size (smaller than earth) -no atmosphere -lowlands flooded by ancient lava flow -caloris basin -geologically dead -very dense -thicker core than earths -low gravity
Earth
-3rd planet from the Sun -green and blue -terrestrial -1 moon -metal core -strong magnetic field protects from solar winds
Mars
-4th planet from the Sun -reddish/butterscotch -terrestrial -2 moons -has seasons because of its tilted rotation axis -weak surface gravity -small -big dust storms -heavily cratered -there was once water because it has runoff and outflow channels -eccentric orbit -reverse greenhouse effect -largest volcano- olympus mons
Jupiter
-5th planet from the Sun -layers of white, red, orange, brown and yellow -jovian -67 moons- called Galilean moons(lo, europa) -has 4 rings -looks flat because of its fast rotation -more than twice the mass of all the other planets combined -its mostly hydrogen and a little helium -large inner core, rocky -excess energy from its formation -magnetic field from its metallic hydrogen layer -not dense at all -most massive planet -great red spot is a giant hurricane
Saturn
-6th planet from the Sun -dull yellow -jovian -has 62 moons (telesto, calypso, tethys, lapetus, mimas, biggest-titan) -has 7 rings made of rock and ice -weaker surface gravity, thick atmosphere -core is 10x the size of earth -has hydrogen and helium -very large
Uranus
-7th planet from the Sun -green blue color -jovian -27 moons (miranda) -methane abundance -flatish due to fast rotation -discovered in 1781 -greatest tilt or rotation (basically sideways) -magnetic field created by a layer of conducting water -almost no magnetic field -discovered by telescope by william hershcel
Neptune
-8th planet from the sun -bright blue -jovian ice planet -134moons -more methane than Uranus -discovered by mathematical prediction by Galileo in 1846 -the great dark spot was a huge storm but it disappeared -has thin ice rings
Venus
-the 2nd planet from the Sun -yellowish white/reddish brown -terrestrial -no moons -similar to earth in size, composition, density, and gravity -molten iron core, big enough for magnetic field but it rotates too slow -thick clouds in the atmosphere -smooth and flat with the exception of mountains and a lot of ongoing volcanos (80%) -CO2 atmosphere winds gong 300-400k -rotation is slow and retrograde(EW) -hot, dry and dusty -greenhouse effect made the temp raise by hundreds of degrees -no plate tectonics
Saturn's icy-rocky core is roughly
10 times more massive than planet Earth.
As seen from Earth, Mars exhibits a retrograde(EW) loop about once every
2 years.
How fast do the upper-level winds over Venus move?
300−400 km/h
Jupiter's magnetosphere extends far into space, stretching about
5 astronomical units
Compared with Earth's orbit, the orbit of Jupiter is approximately
5 times larger.
In the 1950s, radio observations first hinted, and probes later established, that Venus emitted a blackbody spectrum characteristic of a temperature near what value?
730 K
What is the Io plasma torus?
A doughnut-shaped region of energetic heavy ions that follows Io's orbital track
What evidence do we have for habitable Earth-like planets orbiting other stars?
A handful "super-Earths" and "exo-Earths" have been discovered within the predicted habitable zones for their stars.
What is the habitable zone of a star?
A star's habitable zone is an imaginary three-dimensional shell around that star, where temperatures are just right for liquid water to exist in vast quantities.
What seems to be the most common feature of the landing sites of the various Mars missions?
Evidence for water at some point in Mars' history
Why does Saturn have only about half as much helium as a fraction of its total atmospheric composition as Jupiter, Uranus, and Neptune?
Helium may have liquefied and precipitated down into the interior of Saturn, reducing the overall proportion of helium in the atmosphere.
Why did astronomers suspect there was an eighth planet beyond Uranus?
Irregularities in the motion of Uranus suggested that gravity from another planet was affecting it.
What evidence suggests that Triton is a captured moon?
It has a retrograde(EW), highly inclined orbit.
Miranda's appearance suggests which of the following statements?
It has been catastrophically disrupted and reassembled several times.
The most massive planet in the solar system is
Jupiter
The high abundance of iron on the surface of Mars is indicative of what difference between Earth and Mars?
Mars never melted as extensively as Earth.
Why were Martian volcanoes able to grow so large compared to Earth?
Mars's weaker surface gravity
Solar system order
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune My Very Educated Mother Just Served Us Nachos
The farthest major planet from the Sun is
Neptune
What was the first planet discovered by mathematical prediction?
Neptune
If we lived in a solar system outside of our own, would we be able to detect Earth using Doppler measurements of our Sun's "wobble"?
No. The Doppler shifts would be too small for us to detect.
Which of the following Mars surface features provides dramatic evidence that volcanism has played a role in shaping the surface of Mars?
Olympus Mons
Which of the following statements correctly describes the motion of the particles in Saturn's rings?
Particles in the inner rings orbit Saturn at a faster speed than particles in the outer rings.
Why does Europa have so few impact craters?
Recent activity in its icy crust has erased most craters.
Assuming that features you see on Mars are similar to features found on Earth, what would a casual inspection of the interactive photo of Mars lead you to suspect about water on Mars?
Surface water only exists as frozen ice.
What is the most significant difference between the Great Dark Spot of Neptune and the Great Red Spot of Jupiter?
The Great Dark Spot has disappeared, whereas the Great Red Spot has been seen for hundreds of years.
For many years, people thought they saw seasonal changes in Mars's surface markings reminiscent of the growth of vegetation on Earth. What was the actual source of these changes?
The changes were due to large-scale dust storms.
How does Jupiter exhibit differential rotation?
The equatorial zones rotate in less time than the higher latitudes.
How do the overall colors and appearance of Uranus and Neptune differ from those of Jupiter and Saturn? Choose the correct description.
The outer jovian planets' differ from inner jovian planets in their blue coloration.
Why does the appearance of Saturn's rings change over time as seen from Earth?
The rings lie in the planet's equatorial plane, which is tilted with respect to the ecliptic.
Which of the following is the best description of our knowledge of the surface of Venus?
The surface is extremely dry, with evidence of past volcanic events.
What is a hot Jupiter?
They are massive exosolar gas planets that orbit very close to their stars, most within 0.1 astronomical units.
As a percentage of their total volumes, how do the cores of Uranus and Neptune compare with those of Saturn and Jupiter?
Their cores are larger than those of Jupiter and Saturn.
The magnetic fields in all planets are generated by the dynamo effect, caused by rapidly rotating and conducting material flowing in the interiors of the planets. We have just seen that all four of the jovian planets have magnetic fields. Earth also has a planetary magnetic field, but Venus does not, although it is very similar to Earth in mass. Which of the following would be a reason why Venus does not have a magnetic field?
Venus's very slow rotation rate does not allow a magnetic field to form.
Is our solar system unusual among planetary systems?
While it is certainly true that just about all of the planetary systems found so far are very different from our known, it is premature to think that our solar system may be a special case.
Which of the following exoplanets would be easy to detect?
a Jupiter-sized planet orbiting close to a star
What has created Uranus's magnetic field?
a layer of conducting water
Jupiter's moon Europa might harbor life because it has which of the following conditions?
a liquid water subsurface layer
What is a reasonable description of the Great Red Spot?
a very large hurricane
Mimas is a moon of Saturn with which of the following characteristics?
a very large impact crater and a role in maintaining one of Saturn's rings
The atmospheric pressure at the surface of Titan is
about 1.5x greater than the atmospheric pressure at Earth's surface.
Small planets were created through which process?
accretion/accumulation/buildup
The five largest moons of Uranus
all orbit directly above the planet's equator.
A tidally locked moon
always presents the same face to the planet
The moons Telesto and Calypso, orbiting at the Lagrangian points of Saturn and the moon Tethys,
always stay the same distance apart.
What is a brown dwarf?
an object with more mass than Jupiter, but not enough mass to become a star
The moons of Mars
are probably captured asteroids.
Which of the following characteristics describes the conditions that prevail on the surface of Venus?
hot, dry, and dusty
Models that explain the formation of the solar system through a series of gradual steps are considered evolutionary theories. What are models that explain the formation of certain objects in the solar system through other means considered?
catastrophic theories
Which property of Venus's atmosphere gave rise to the runaway greenhouse effect?
composition of the atmospheric gases
The surface temperature of Saturn, though cold, is much higher than would be expected from the amount of solar energy it receives. Which of the following factors is thought to be the primary cause of this higher temperature?
continued gravitational settling of liquid helium
What are some terms that astronomers have used to describe categories of exoplanets?
hot and cold Jupiters, hot and cold Neptunes, Earths and super-Earths
A gas giant planet orbiting a distant star would be expected to have
evidence for hydrogen in its spectrum.
Of the following, which are most like the particles found in Saturn's rings?
fist-sized snowballs
What did the surface of Venus look like in the photographs taken by the Soviet Venera spacecraft?
flat rocks, small rocks, some eroded, and some finer material
What is the source of Jupiter's excess energy?
gravitational energy from its formation
The jovian planets with the largest diameters also tend to
have magnetic field axes most closely aligned with their axes of rotation.
Moons that show few craters probably
have warm interiors.
Venus's permanent retrograde(EW) rotation about its axis results in the planet
having its north pole below the plane of the ecliptic.
What substance is underabundant (compared to Jupiter) in the atmosphere of Saturn?
helium
