Chapter 7 Flashcards
What is comparative planetology?
The study of planets, moons, asteroids, and comets by comparing their similarities and differences.
What is the first step in understanding our solar system?
Visualizing what it looks like as a whole.
What is the Sun mostly composed of?
Hydrogen and Helium
What percentage of the solar system’s total mass does the Sun contain?
More than 99.8%
What are sunspots?
Spots on the Sun’s surface that appear dark because they are slightly cooler than their surroundings.
Where does the Sun’s energy come from?
Nuclear fusion in its core.
What is the solar wind?
Charged particles flowing outward from the Sun.
What is the average distance of Mercury from the Sun?
0.39 AU
Describe Mercury’s surface.
Desolate, cratered, with no active volcanoes, wind, rain or life
Why does Mercury have extreme temperature variations?
Tidal forces from the sun have forced Mercury into an unusual rotation.
What is unique about Venus’s rotation?
It rotates very slowly and in the opposite direction of Earth.
What is the average surface temperature of Venus?
740 K (470°C or 880°F)
What causes Venus’s extreme temperatures?
An extreme greenhouse effect.
What is unique about Earth compared to other planets in our solar system?
It is the only known oasis of life.
What percentage of Earth’s surface is covered by oceans?
Nearly three-fourths.
What is the leading hypothesis for the Moon’s formation?
A giant impact early in Earth’s history.
What is the average distance of Mars from the Sun?
1.52 AU
What are the names of Mars’ two moons?
Phobos and Deimos
What evidence suggests that Mars had liquid water in the past?
Dried-up riverbeds, rock-strewn floodplains, and minerals that form in water
What is the average distance of Jupiter from the Sun?
5.20 AU
What is the Great Red Spot on Jupiter?
A long-lived storm.
What are the Galilean moons of Jupiter?
Io, Europa, Ganymede, and Callisto
Which of Jupiter’s moons is the most volcanically active in the solar system?
Io
What is the average distance of Saturn from the Sun?
9.54 AU
What are Saturn’s rings made of?
Countless small particles of rock and ice.
What spacecraft has been observing Saturn since 2004?
The Cassini spacecraft
Which of Saturn’s moons has ice fountains spraying out from its southern hemisphere?
Enceladus
Which moon in the solar system has a thick atmosphere?
Titan, a moon of Saturn.
What is the average surface temperature of Earth?
290 K
What are the two distinct groups that the planets fall into?
Inner planets and Outer planets
