Which of the following planets has an exosphere? a) Mars b) Mercury c) Venus d) Earth e) All the above
e) all the above
The sky is blue because
molecules scatter blue light more effectively than red light.
What is the difference in meaning between the terms weather and climate?
Weather refers to short-term variations in conditions, and climate refers to long-term variations in conditions.
Why doesn't Venus have seasons like Mars and Earth do?
Its rotation axis is not tilted.
Why is Mars red?
Its surface rocks were rusted by oxygen.
Venus may have started with an ocean's worth of water. Where is its water now?
The water was lost when ultraviolet light broke apart water molecules and the hydrogen escaped to space.
Which of the following is not product of outgassing? a) nitrogen b) water c) oxygen d) carbon dioxide e) sulfur dioxide
From where did the molecular oxygen in Earth's atmosphere originate?
photosynthesis from single-celled organisms
How much energy does Jupiter emit compared with how much it receives from the Sun?
It emits twice as much
How do astronomers think Jupiter generates it internal heat?
By contracting, changing gravitational potential energy into thermal energy.
Why is Jupiter denser than Saturn?
The extra mass of Jupiter compresses its interior to a greater extent than that of Saturn.
Why is Saturn almost as big as Jupiter, despite its smaller mass?
Jupiter's greater mass compresses it more thus increasing its density;
How do the jovian planet interiors differ?
All have cores of about the same mass, but differ in the amount of surrounding hydrogen and helium.
What is Jupiter's Great Red Spot?
a long-lived, high-pressure storm
Why are there no impact crater on the surface of Io?
Io did have impact craters but they have all been buried in lava flows.
What mechanism is most responsible for generating the internal heat of Io that drives the volcanic activity?
What is the most abundant gas in Titan's atmosphere?
Which of the following statements about Titan is not true? a) It may have an ocean of liquid ethane. b) Its atmosphere is mostly nitrogen c) It is the coldest moon in the solar system. d) Its temperature is too cold for liquid water to exist. e) Its surface is hidden from view by its thick atmosphere.
It is the coldest moon in the solar system.
Which previously unknown planet's location was predicted from mathematical calculations of orbital motions?
Which of the jovian planets have rings? a) Jupiter b) Uranus c) Neptune d) Saturn e) all of the above
e) all of the above
What do asteroids and comets have in common?
Most are unchanged since their formation in the solar nebula.
Why do asteroids and comets differ in composition?
Asteroids formed inside the frost line, while comets formed outside.
What is the size of the largest asteroid?
The combined mass of all the asteroids in the asteroid belt is
less than that of any terrestrial planet.
The large gaps in the asteroid belt (often called Kirkwood gaps) are caused by
orbital resonances with Jupiter.
If we know the size of an asteroid, we can determine its density by
determining its mass from its gravitational pull on a spacecraft, satellite, or planet.
Why aren't small asteroids spherical in shape?
The strength of gravity on small asteroids is less than the strength of the rock.
A typical shooting star in a meteor shower is caused by a ________ entering Earth's atmosphere.
pea-size particle from a comet
Processed meteorites with high metal content probably are
chunks of a larger asteroid that was shattered by a collision.
In order to have a comet named after you, you have to
be one of the first three discoverers who report it to the International Astronomical Union (IAU).
When do comets generally begin to form a tail?
Inside of Jupiter's orbit
Why won't Pluto collide with Neptune?
The two planets have an orbital resonance that prevents them from colliding.
In the asteroid impact theory of the extinction of the dinosaurs some 65 million years ago, the dinosaurs (and over half of all the other species of Earth at that time) died off largely because
dust injected into the stratosphere from the impact absorbed visible light from the Sun, causing global temperatures to plummet,
What is the typical size of comets that enter the inner solar system?
Why do jovian planets bulge around the equator,that is, have a "squashed" appearance?
Their rapid rotation flings the mass near the equator outward.
How does Jupiter's core compare to Earth's?
It is about the same size but is 10 times more massive.
Why is Neptune denser than Saturn?
It has a different composition than Saturn, including a higher proportion of hydrogen compounds and rocks.
How do astronomers think Saturn generates its internal heat?
by raining dense helium droplets from higher to lower altitudes, resembling the process of differentiation.
The belts and zones of Jupiter are
alternating bands of rising and falling air at different latitudes.
The four Galilean moons around Jupiter are
a mixture of rock and ice, with the rock fraction increasing with distance from Jupiter.
Why do Uranus and Neptune have blue methane clouds but Jupiter and Saturn do not?
Methane does not condense into ice in the warmer atmospheric temperatures of Jupiter and Saturn.
The fact that most moons always show the same face to their planet is
a natural consequence of tidal forces acting on the moons.
What is the most important reason why an icy moon is more likely to be geologically active than a rocky moon of the same size?
Ice has a lower melting point than rock.
Which moon has the most substantial atmosphere?
Why does Titan have such a nitrogen-rich atmosphere?
The nitrogen comes from the breakup of ammonia (NH3) by solar radiation and subsequent thermal escape of the hydrogen.
Planetary rings are: a) Orbiting in the equatorial plane of their planet b) composed of a large number of individual particles that orbit their planet in accord with Kepler's third law. c) known to exist for all of the jovian planets. d) nearer to their planet than any of the planet's large moons. e) all of the above
e) all of the above
Most of the planets discovered around other stars
are more massive than Earth and orbit very close to the star
current techniques can measure stellar motion to less than
The composition of a planer can be determined by
The astrometric technique of planet detection works best for
big planets in edge-on orbits around small stars.
The reason that most extrasolar planets are found close to their parent stars is
the amount and frequency of the star's motion are both higher.
Which planet can we see occasionally transit across the face of the Sun?
A planet is detected via the Doppler technique. The repeating pattern of the stellar motion tell us
The orbital period of the planet.
The depth of the dip in a star's brightness due to the transit of a planet depends most directly on
the planets size.
How do we think the "hot Jupiters" around other stars were formed?
They formed as gas giants beyond the frost line and then migrated inwards.
Which of the following is a consequence of the discovery of hot Jupiters for understanding our own Solar System?
It shows that we do not fully understand the formation of our Solar System.
Why are many of the newly detected extrasolar planets called "hot Jupiters"?
Their masses are similar to Jupiter but they are very close to the central star and therefore hot.
Approximately how many other planetary systems have been discovered to date?