Planetary Atmospheres
The __________ of a planet's atmosphere is, in part, due to the strength of the planet's
gravitational field. A very massive planet with a very strong __________ _______ is
likely to have a very thick atmosphere. Jupiter, Saturn, Uranus, and Neptune, for
example, have strong gravitational fields and thick, dense atmospheres. Mercury, on the
other hand, has a weak gravitational field and an extremely thin, low-density
atmosphere. In fact, the particles in ____________ atmosphere are so far apart that they
are more likely to collide with the planet's surface than with each other.
_________ has a very thick, dense, cloudy atmosphere that hides the planet's surface
from view. The atmosphere of Venus is made mostly of carbon dioxide (96.5%), with a
lesser amount of nitrogen (3.5%) and trace amounts of other gases, including sulfur
dioxide, argon, and water vapor. The main __________ of Venus's atmospheric gases is
volcanic eruptions that occurred earlier in its history, although impacting objects may
have added some materials as well. Because of the high concentration of carbon
dioxide, Venus has a "runaway" ____________ ____________ that is much stronger
than Earth's greenhouse effect. Because of its powerful greenhouse effect and its
distance from the Sun, Venus has a surface temperature of about 465°C (870°F), which
is the highest of all the planets.
Planetary Atmospheres
The __________ of a planet's atmosphere is, in part, due to the strength of the planet's
gravitational field. A very massive planet with a very strong __________ _______ is
likely to have a very thick atmosphere. Jupiter, Saturn, Uranus, and Neptune, for
example, have strong gravitational fields and thick, dense atmospheres. Mercury, on the
other hand, has a weak gravitational field and an extremely thin, low-density
atmosphere. In fact, the particles in ____________ atmosphere are so far apart that they
are more likely to collide with the planet's surface than with each other.
_________ has a very thick, dense, cloudy atmosphere that hides the planet's surface
from view. The atmosphere of Venus is made mostly of carbon dioxide (96.5%), with a
lesser amount of nitrogen (3.5%) and trace amounts of other gases, including sulfur
dioxide, argon, and water vapor. The main __________ of Venus's atmospheric gases is
volcanic eruptions that occurred earlier in its history, although impacting objects may
have added some materials as well. Because of the high concentration of carbon
dioxide, Venus has a "runaway" ____________ ____________ that is much stronger
than Earth's greenhouse effect. Because of its powerful greenhouse effect and its
distance from the Sun, Venus has a surface temperature of about 465°C (870°F), which
is the highest of all the planets.
Although not as _________ and dense as Venus' atmosphere, _______ atmosphere is thicker and
denser than the atmospheres of the other rocky, inner planets. Earth's atmosphere developed from volcanic
eruptions, biological processes, and early impacts by __________ and asteroids.
Mars has a thin, low-density atmosphere. The _________ pressure on the surface of Mars is only about
1/150 the atmospheric pressure on Earth's surface. Mars' atmosphere came mainly from past ___________
eruptions, with additional contributions likely from ____________ bodies.
Past Mars, the planets of the solar system have very ________ and thick atmospheres. Jupiter, Saturn,
Uranus, and Neptune are giant balls of _______ and compressed ____________ (with very small rocky-icy
cores). Their atmospheres formed very early in the history of the solar system and have changed very
little. These planets are much __________ than the inner planets and are much more __________.
In general, when planets or moons have thick atmospheres, they tend to experience a relatively
___________ range of surface temperatures from day to night. Planets or moons with thin atmospheres often
experience ___________ large surface temperature __________. For example, the Moon is much less
massive than the Earth and has almost no atmosphere. Because it lacks a thick atmosphere to regulate its
temperature, the Moon has a much wider surface temperature _______ than Earth. The same is true of
____________, which has a very thin atmosphere and whose surface temperature varies by about 600°C from
day to night.
Although not as _________ and dense as Venus' atmosphere, _______ atmosphere is thicker and
denser than the atmospheres of the other rocky, inner planets. Earth's atmosphere developed from volcanic
eruptions, biological processes, and early impacts by __________ and asteroids.
Mars has a thin, low-density atmosphere. The _________ pressure on the surface of Mars is only about
1/150 the atmospheric pressure on Earth's surface. Mars' atmosphere came mainly from past ___________
eruptions, with additional contributions likely from ____________ bodies.
Past Mars, the planets of the solar system have very ________ and thick atmospheres. Jupiter, Saturn,
Uranus, and Neptune are giant balls of _______ and compressed ____________ (with very small rocky-icy
cores). Their atmospheres formed very early in the history of the solar system and have changed very
little. These planets are much __________ than the inner planets and are much more __________.
In general, when planets or moons have thick atmospheres, they tend to experience a relatively
___________ range of surface temperatures from day to night. Planets or moons with thin atmospheres often
experience ___________ large surface temperature __________. For example, the Moon is much less
massive than the Earth and has almost no atmosphere. Because it lacks a thick atmosphere to regulate its
temperature, the Moon has a much wider surface temperature _______ than Earth. The same is true of
____________, which has a very thin atmosphere and whose surface temperature varies by about 600°C from
day to night.