Chapter 9 ,

______ km is the approximate diameter of the largest asteroid

1,000 1,000 km is the approximate diameter of the largest asteroid

The discovery of _____ allowed astronomers to determine Pluto's _____.

Charon , mass The discovery of Charon allowed astronomers to determine Pluto's mass.

__________ objects are known to have ______.

Kuiper belt, moons Kuiper belt objects are known to have moons.

Objects in the _____ ______ contain large proportions of ___

Oort cloud , ice.

____is most like a comet.

Pluto Pluto is most like a comet.

Charon is the largest of ______ , _____known moons.

Pluto's, five Charon is the largest of Pluto's five known moons.

Objects in the ______ ________ and _______ _______ orbit the Sun in nearly the _____ plane as the planets, but objects in the Oort cloud do not.____ ____

asteroid belt, Kuiper belt, same , do not Objects in the asteroid belt and Kuiper belt orbit the Sun in nearly the same plane as the planets, but objects in the Oort cloud do not.

Suppose that large Jovian planets had never formed in our solar system, neither the______ ______ nor _____ _______ would exist.

asteroid belt, Oort cloud Suppose that large Jovian planets had never formed in our solar system, neither the asteroid belt nor Oort cloud would exist.

The plasma tail of a comet always points most directly _______ from the Sun.

away The plasma tail of a comet always points most directly away from the Sun.

A spacecraft has ________ and brought material to Earth from a _____

captured , comet. A spacecraft has captured and brought material to Earth from a comet.

Pluto has long been known to be _____from the planets in the following ways: It is composed primarily of____ , it has a ______ ______ _____, it is far_____ than the terrestrial planets, its orbit is more ______to the ecliptic plane

different , ices, highly eccentric orbit, smaller, inclined Pluto has long been known to be different from the planets in the following ways: It is composed primarily of ices, it has a highly eccentric orbit, it is far smaller than the terrestrial planets, its orbit is more inclined to the ecliptic plane

During the time that a comet passes through the _____solar system, the comet can appear quite ____because sunlight _____ off the comet's tail and coma.

inner, bright, reflects During the time that a comet passes through the inner solar system, the comet can appear quite bright because sunlight reflects off the comet's tail and coma.

Suppose there were no solar wind. A comet in our _____ solar system would have only ___ ___ instead of ____.

inner, one tail , two Suppose there were no solar wind. A comet in our inner solar system would have only one tail instead of two.

If we could put all the asteroids together, their total ____ would be much ____than the mass of any terrestrial planet.

mass, less If we could put all the asteroids together, their total mass would be much less than the mass of any terrestrial planet.

A rock found on Earth that crashed down from space is called a ________

meteorite. A rock found on Earth that crashed down from space is called a meteorite.

Objects in the asteroid belt are made mostly of ___ and _____.

rock, metal Objects in the asteroid belt are made mostly of rock and metal.