Chapter 8: The Solar System

Eris

________ is about 2, 400 km in diameter and has one moon.

Uranus

________ has at least 27 moons and also has a thin ring system made of eleven separate rings.

Saturn

________ is the second- largest planet in the solar system, but it has only about one- third as much mass as Jupiter.

Martian Atmosphere

The ________ is much thinner than Earths and is composed mostly of carbon dioxide, with some nitrogen and argon.

Astronomical Unit

________: Used to measure the large distances within the solar system; equals the average distance from Earth to the Sun, about 150 million km.

Surface Temperatures

________ on Earth allow water to exist as a solid, a liquid, and a gas.

Ptolemy

________ presented his geocentric model of the solar system in 140 A.D.

Mercurys

________ relatively large core and thin outer layers resulted in some extreme differences in its surface terrain.

Galileo

________ was the first to discover these moons when he looked through his telescope and he drew a picture of what he saw.

Mariner

________ 10 was the first American space probe sent to Mercury.

Mars

________ has two small, heavily cratered moons called Phobos and Deimos.

Earth

Unlike ________ and the other planets, Uranuss axis of rotation is tilted so that it is nearly parallel to the plane of the planets orbit.

Jupiter

________ is the largest planet and contains more than twice the mass as all other planets combined.

Astronomers

________ have devised new techniques and instruments to find planets around other stars.

Uranus’s

________ atmosphere contains about 83 percent hydrogen, 15 percent helium, 2 percent methane, and traces of other gases.

Mercury

________ is small and has a relatively weak gravitational pull.

Neptune

________ has at least 13 moons.

Alvin

________ also discovered colonies of bacteria living off the extremely hot material spewing from volcanic vents.

Sedna

________ has been labeled a distant planetoid and with a diameter of 1, 200 to 1, 700 km, it is smaller than Pluto, but larger than comets in the Kuiper Belt.

clouds

The ________ in the atmosphere also contain droplets of sulfuric acid, which gives them a slightly yellow color.

Europas ocean

________ could hold more than twice the amount of water that Earths oceans hold.

Orbits of Mars

Most asteroids are found in a belt between the ________ and Jupiter.

asteroids

They may have formed when ________ collided or when comets passed close to the Sun, leaving a trail of debris.

Meteoroids

________: Other rocky objects orbiting within the solar system.

Comet

________: composed of dust and rock particles mixed with frozen water, methane, and ammonia.

Atmosphere

The ________ of Venus, which has 92 times the surface pressure of Earths at sea level, is mostly carbon dioxide.

Heliocentric Model

________: Sun- centered model of the solar system.

Venus

________: the second planet from the Sun.

Mars

________ is tilted 25° on its axis, which is very close to Earths tilt.

Jupiter

________ has more than 60 moons.

Galileo

________ concluded that Earth and Venus revolve around the Sun and that the Sun is the center of the solar system.

Uranus

________: the seventh planet from the Sun.

Neptune

________ was discovered in 1846 after studies of Uranuss orbit indicated that the orbit was being affected by gravity of another unseen planet.

Saturn

________ is composed almost entirely of hydrogen and helium, with traces of methane, ammonia, and water vapor.

Earths

Ozone in ________ atmosphere also protects life from the Suns intense radiation.

Sedna

________ comes as close as 76 AU from the Sun, but travels to a distance of 950 AU- far beyond the Kuiper Belt, but much closer than the Oort Cloud.

Asteroids

________: Rocky objects formed from material similar to that of the planets.

Comets

________ often have two tails- one made of dust and one made of ions.

Mercury

________: The smallest and closest planet to the Sun.

Neptune

________: the eighth planet from the Sun.

Jupiter

________: The fifth planet from the Sun.

Mars

________ has been a priority of NASA planetary exploration for several decades.

Mercury

________ is covered by craters, some of which have double rings.

Mars

________ is called the red planet because iron oxide in some of the weathered rocks on its surface gives it a reddish color.

Heliocentric Model

Sun-centered model of the solar system

Astronomical Unit

Used to measure the large distances within the solar system; equals the average distance from Earth to the Sun, about 150 million km

Extrasolar Planets

planets in orbit around other stars

Mercury

The smallest and closest planet to the Sun

Venus

the second planet from the Sun

Earth

The third planet from the Sun

Mars

The fourth planet from the Sun; red planet

Jupiter

The fifth planet from the Sun

Saturn

the sixth planet from the Sun

Uranus

the seventh planet from the Sun

Neptune

the eighth planet from the Sun

Comet

composed of dust and rock particles mixed with frozen water, methane, and ammonia

Asteroids

Rocky objects formed from material similar to that of the planets

Meteoroids

Other rocky objects orbiting within the solar system

Extraterrestrial Life

life on other worlds

Vast Disk of Icy

Most comets come from a(n) ________ comets called the Kuiper Belt near Neptunes orbit, or from the Oort Cloud that surrounds the solar system.

Mercury

The magnetic field around ________, discovered by Mariner 10, indicates that ________ has a much larger iron core than would be expected and is missing some lighter materials you would expect to find in its mantle.

Continuous storms of swirling, high

pressure gas have been observed on Jupiter

The structure of the rings is caused by the gravitational inter

action between the ring particles and some of Saturns moons