The Solar System-7th Grade

Why do scientists study comets, meteoroids, and asteroids?

Comets and asteroids are probably composed of material that formed early in the history of the solar system. Scientists study the structure and composition of these space objects to better understand what the solar system may have been like long ago.

Why do the planets orbit the Sun?

The Sun contains 99.86% of the mass of the entire solar system. Because of its gravitational pull, the Sun is the central object around which the objects of the solar system revolve.

When small pieces of rock moving through space enter Earth's atmosphere and completely burn up, they are called ______________. a. comets b. Meteors c. meteorites d. asteroids

b. meteors

____________ published the Sun-centered model of the solar system in 1543. a. Kepler b. Magellan c. Copernicus d. Galileo

c. Copernicus

Label the following planets in order by size (largest to smallest): Earth Saturn Jupiter Mars Neptune Uranus Mercury Venus

Jupiter Saturn Uranus Neptune Earth Venus Mars Mercury

Label the following planets as outer or inner planets: Earth Saturn Jupiter Mars Neptune Uranus Mercury Venus

Outer: Neptune, Saturn, Jupiter, Uranus Inner: Earth, Mars, Mercury, Venus

List the evidence that large amounts of water were once present on Mars.

There are polar ice caps; iron in Mars's crust may have been leached out by groundwater; there are gullies and sediment deposits possibly formed by water flows; many dried up channels exist on the planet's surface.

What is unique about Uranus?

Uranus's rotational axis is nearly parallel to the plane of its orbit.

The closest moon to Jupiter, ______________, is volcanically active. a. Io b. Callisto c. Ganymede d. Europa

a. Io

Scientists theorize that the asteroid belt did not form a planet because ____________. a. Jupiter's gravity kept it from from forming b. Some of the particles were too large c. it was too rocky d. Some of the particles moved too slowly

a. Jupiter's gravity kept it from forming

The largest known volcano in the solar system in an extinct volcano known as Olympus Mons found on the planet _____________. a. Mars b. Jupiter c. Mercury d. Venus

a. Mars

A cloud of gases around the solid portion of a comet is known as the ______________. a. coma b. core c. heart d. nucleus

a. coma

Who proposed a Sun-centered solar system? a. Ptolemy b. Copernicus c. Galileo d. Oort

b. Copernicus

___________is the largest moon in the solar system. a. Callisto b. Ganymede c. Earth's moon d. Io

b. Ganymede

Two of the inner planets are _____________________________. a. Mars and Jupiter c. Earth and Saturn b. Mercury and Mars d. Uranus and Neptune

b. Mercury and Mars

Methane gives _________________________their blue-green color. a. Mars and Earth c. Saturn and Jupiter b. Uranus and Neptune d. Neptune and Venus

b. Uranus and Neptune

__________ axis of rotation is nearly parallel to the plane of its orbit. a. Mars' b. Uranus' c. Mercury's d. Earth's

b. Uranus'

A planet that is very hot and has sulfuric acid in its clouds is ____________________. a. Mars b. Venus c. Mercury d. Earth

b. Venus

The Great Red Spot, a continuous storm, is located on the planet _____________. a. Saturn b. Uranus c. Jupiter d. Neptune

c. Jupiter

Most asteroids are located in an area between the orbits of _____________. a. Earth and Mars c. Mars and Jupiter b. Jupiter and Saturn d. Mercury and Venus

c. Mars and Jupiter

The second smallest planet and the one closest to the Sun is ____________________. a. Mars b. Venus c. Mercury d. Jupiter

c. Mercury

At times, the planet ____________ is actually the farthest planet from the Sun. a. Uranus b. Saturn c. Neptune d. Jupiter

c. Neptune

The planet with the lowest density and hundreds of thin rings is _________________. a. Jupiter b. Uranus c. Saturn d. Neptune

c. Saturn

Johannes Kepler discovered that the orbits of the planets are ___________________. a. parabolic b. circular c. elliptical d. spherical

c. elliptical

____________ are small pieces of rock moving through space. a. Comets b. Meteors c. Meteoroids d. Meteorites

c. meteoroids

The planet that averages 150 million km, or one AU. from the Sun is _____________. a. Mars b. Jupiter c. Mercury d. Earth

d. Earth

A planet that appears reddish-yellow due to iron oxide in its rocks is ______________. a. Mercury b. Jupiter c. Uranus d. Mars

d. Mars

The solid portion of a comet is called its ____________. a. coma b. core c. heart d. nucleus

d. Nucleus

The largest of ______________ moons. Titan, is larger than the planet of Mercury. a. Neptune's b. Pluto's c. Uranus' d. Saturn's

d. Saturn's

Two planets with similar mass and size are ________________________. a. Mercury and Jupiter c. Earth and Pluto b. Saturn and Uranus d. Venus and Earth

d. Venus and Earth

Pieces of rock that usually strike Earth's surface are called _______________. a. meteoroids b. comets c. meteors d. meteorites

d. meteorites