Astronomy Flashcards
the planet closest to the sun in the solar system
Mercury
all planets…
revolve around the sun in the same direction
terrestrial planets
mercury, venus, earth, mars
jovian planets
jupiter, saturn, uranis, neptune
what do all 4 terrestrial planets have in common
solid surface with geological activity on them
is jupiter more or less dense than earth?
less dense
compared to the mass of the sun, the mass of the earth is pretty insignificant (T/F)
True
the term “solar system” refers to the sun & everything that orbits around it (T/F)
True
more than 90% of the mass of the solar system is found in the 4 giant planets (T/F)
False
all planets in the solar system are similar in terms of what materials theyre mostly made of (T/F)
False
the 8 planets may be different in size but they all have roughly the same density (T/F)
False
The giant planets are made of much lighter (less dense) materials than the terrestrial planets (T/F)
True
comets are mostly icy chunks, while asteroids are mostly rocky chunks left over from the formation of the solar system (T/F)
True
Among the giant planets, only saturn has rings (T/F)
False
Among the terrestrial planets, earth is the smallest (T/F)
False
what planet can come closest to earth in its orbit and look brightest in our skys?
Venus
what gas makes up most of the atmosphere of Mars and Venus?
Carbon Dioxide
Why does Mars have an overall reddish color when we see its surface from afar?
material contains a lot of iron dioxide, the same chemistry making rusting metals look reddish
the planet that most resembles earth in size and internal composition
venus
what is NOT a way Venus resembles earth?
the thickness and pressure of its atmosphere
what wavelength of electromagnetic radiation would be used to examine the surface of a planet which is covered by a thick layer of clouds all the time
radio waves (radar)
why are there no smaller craters on the surface of Venus, only bigger ones?
Venus has a thick atmosphere all smaller chunks of material burn up before reaching the surface
the process by which Venus becomes so much hotter than earth is:
runaway greenhouse effect
what is one way that humans are currently making the atmosphere of earth more like venus?
adding carbon dioxide and other greenhouse gases into the atmosphere… leading to global warming
A crucial difference that helps explain why Venus is so hot and the Earth isn’t is that:
on Venus, there was eventually no ocean to remove carbon dioxide from the atmosphere
The largest volcano on Mars is called
Olympus Mons (Mt. Olympus)
One way in which Mars closely resembles the Earth is:
the length of its day (period of rotation)
Droplets of liquid water rain irrigate the surface of mars regularly (t/f)
False
What makes astronomers believe that Mars once had rivers and running water
Images from orbiting spacecraft reveal ancient channels that look like dried-up river beds on Earth (and our rovers show geological formations made by running water)
On some parts of Mars, it gets cold enough for a gas to freeze out of the atmosphere that does not freeze out by itself at the temperatures and pressures on Earth. This gas makes up some of the polar caps on Mars and is:
carbon dioxide
What factors can account for the differences in crater counts among these objects?
Water erosion erases some craters. Volcanic activity erases some craters. Having an atmosphere offers protection from some impacts. Plate tectonics erases some craters.
Which of the following statements best explains why Earth has a strong magnetic field while Mars does not?
Mars is small; it cooled faster, so its liquid core is less molten now.
Mars lacks oxygen in the atmosphere (t/f)
True
All Jovian planets have natural satellites around them and none of the terrestrials do (t/f)
False
By far the most abundant element in the giant (jovian) planets is
hydrogen
The largest planet in the solar system (by mass) is
Jupiter
Jupiter has enough mass to make 318 Earths. In contrast, Uranus and Neptune have only enough mass to make
15 Earths
The element that can act like a metal when it is under tremendous pressure and is probably responsible for Jupiter and Saturn’s magnetism is
hydrogen
The planet that orbits “on its side” (i.e. has its rotation axis parallel to the plane of its orbit) is
Uranus
Astronomers believe that Jupiter’s strong magnetic field is caused by
a huge layer of metallic hydrogen inside Jupiter
One reason that we have such a complex system of belts/zones/storms in Jupiter’s atmosphere is that
the planet rotates very rapidly
What is the primary source of Jupiter’s internal heat?
Gravitational contraction
Suppose a planet is discovered orbiting another star. Careful analysis reveals this planet’s diameter to be approximately 3 Earth diameters. Based on this figure, using our solar system as a reference model, what is its approximate mass?
10 Earth masses
Each of the giant (jovian) planets have a lot more moons that any terrestrial planet
True
The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?
carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect
Which part of the Earth has the greatest density?
core
An increase in the Earth’s temperature by several degrees Celsius would result in
the melting of many glaciers, a rise in sea levels, and more flooding of towns near the coasts of the continents
We believe the maria on the Earth’s Moon are
ancient impact craters in which lava beds welled up from inside the Moon
The lunar highlands are made mostly of rocks that
rose to the top as the Moon cooled from a molten state early in its history
These days the theory of the Earth’s Moon’s origin that best fits with the facts we have about the Moon is
a large object hit the Earth and the collision produced a filament of material that condensed to make the Moon
The largest and most massive of Saturn’s rings is the
B ring
Identify the property that distinguishes a dwarf planet from a (“major”) planet.
Has not cleared its orbital neighborhood of similar objects
Saturn’s rings are made of billions of individual “moonlets” (small chunks) (t/f)
True
Pluto’s big satellite is called
Charon
Our modern understanding of Pluto is that it is a member of
the Kuiper Belt (of trans-Neptunian objects)
Pluto has rings (t/f)
False
Which substance plays the same role on Titan as water does on Earth (existing as gas, liquid, and solid)?
methane
The world in the solar system that is most active volcanically is
Io
The satellite whose surface is characterized by a smooth icy crust with a complex network of cracks is:
Europa
A main difference between asteroids and comets is that asteroids are mostly made of rock and comets are mostly made of
Ice
Which part of a comet is the DENSEST?
Nucleus
Comets ALWAYS have a tail, even when far away from the sun (t/f)
False
Which of the following is NOT a characteristic that worlds in our solar system have in common:
that all the planets have solid surfaces on which we can see impact craters
Astronomers call the vast, rotating cloud of vapor and dust from which the solar system formed
a solar nebula
Astronomers now believe that the differences in composition among the planets reflect what characteristic in the early solar system?
temperature
A key difference between the protoplanets that formed in the outer solar system and those that formed in the inner solar system was that
those in the outer solar system were in a place where ice, not just rock, condensed and thus could grow larger
For solid rocky worlds, a general rule is
the larger the world, the slower it cools off and the more it will keep its internal heat
Some of the early planetesimals that formed the solar system still survive today. Where would you find such planetesimals?
in the asteroid and Kuiper belts
Based on the solar nebula model, why wouldn’t we expect a terrestrial planet to form in the outer solar system?
In the outer solar system, anything that was massive enough to form a terrestrial planet-sized object would likely have succeeded in also drawing a lot of ices and H and He to itself, producing a gas giant.
As a cool gas cloud collapses to form a star and planetary system, it
Speeds up its rotation and flattens
Our solar system is believed to have formed following the collapse of a
Giant gas cloud
Venus has a thick cloud containing sulfuric acid droplets (t/f)
True
What features are abundant on Callisto and Ganymede
Impact craters
Pluto is a member of…
Kuiper Belt
Gravity of the comet nucleus holds on the evaporated material and it freezes back into the nucleus (t/f)
False
Astronomers were surprised to find this in the Kuiper Belt
Larger bodies, with sizes as big as Pluto (now called dwarf planets)
Asteroids are round (t/f)
False
