Sees Stars

Vocabulary Term: star A burning sphere of gases. The sun is our nearest star. Even though it is constantly exploding in a nuclear reaction, the sun and other stars are so large and have so much matter in them that it will take billions of years for the explosion to use all the "fuel" in the star.

Sun Facts Largest object in the solar system. The sun is the source of almost all of the energy in the solar system. Some of the energy reaches Earth as light and some as heat.

Vocabulary Term: Constellations Groups of stars that have been given names. Example: A star group called the Big Dipper is part of the constellation Ursa Major, which means “Big Bear” in latin.

Constellation Fact Scientists use a list of only 88 official constellations.

Observing the Night Sky If you observed the stars carefully for a whole night, you would notice that stars seem to move. Like the sun and moon, they appear to travel from east to west across the sky. This is caused by Earth rotating as it travels around the sun.

As the seasons change, we see different constellations in the night sky.

Mississippi Northern Hemisphere Winter: Orion is high in the night sky. Summer: Scorpio is visible only in summer.

Orion

Scorpio

How scientists first observed planets. As early scientists observed the night sky, they noticed that a few bright stars were different. These stars seem to move more slowly or quickly than the unchanging constellations. These “wandering stars” are what we now know as planets.

Vocabulary Term: planet A large object that moves around a star.