The solar system is the Sun and the objects that travel around it. The Earth is part of the solar system because it also travels around the Sun. The Sun is a star similar to the other stars in the sky but it is much closer to the Earth. The Sun is mostly a big ball of gases composed mainly of hydrogen and helium.

There are seven other planets that travel around the Sun, too. These planets, in order, include Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. Earth is located between Venus and Mars. The path the planets use when traveling around the Sun is oval-shaped and is called its orbit. Each of the planets in the solar system take a different amount of time to orbit or travel around the Sun.

The planet Earth takes 365 days or one year to orbit the Sun. The other planets take more or less time to orbit the Sun. It takes Mercury less than two months or 88 days to travel around the Sun. It is the shortest time compared to the other planets. The planet taking the longest time to go around the Sun is Neptune. It takes Neptune almost 165 years to travel around the Sun.

Other objects in space include the moons of six planets. A moon is a celestial object (object in space) that orbits another body in space. There are approximately 173 moons throughout the solar system. Earth has a single moon, Mercury and Venus have none, and the planet with the most moons is Jupiter with 63. Not far behind Jupiter is Saturn with 62 moons.

The asteroid belt is another object in the solar system. The asteroid belt is approximately located between the orbits of the planets Mars and Jupiter. The asteroid belt contains irregularly shaped bodies called asteroids which are believed to be leftovers from the beginning of the solar system 4.6 billion years ago. The objects are rocky and irregular in shape, and some may be hundreds of miles across, but most of the asteroids are very small.

41.

The Sun and the objects that travel around it is called ________________.

A. the planets          B. the solar system           C. the moons        D. the asteroid belt

42.

Which planet takes the shortest time to orbit the Sun?

A. Mercury            B. Neptune                         C. Venus               D. Jupiter

43.

Which planet has no moon?

A. Venus and Mars                            B. Saturn and Neptune

C. Mercury and Saturn                      D. Mercury and Venus

44.

Which of the following is the definition of an asteroid?

A. Irregularly shaped bodies which are believed to be leftovers from the beginning of the solar system

B. Celestial objects that orbits another body in space

C. Similar to stars in the sky but they are much closer to the Earth

D. The name of the rings encircling several planets of the solar system

45.

The word “objects” in paragraph 5 refers to ___________.

A. orbits                      B. planets                C. asteroids                    D. belts