Astronomy for Kids: Learn About the North Star and Southern Cross
The North Star: Polaris
The North Star is a very important star because it is often used for navigation. Navigation means knowing where you are and finding where you want to go. Polaris, or the North Star, is almost directly above the North Pole. When you locate Polaris you will know how to go north.
The North Star is easy to find if you look for the Big Dipper, which is part of the constellation Ursa Major. A constellation is a group of stars that seem to make a picture in the sky. Ursa Major is the great bear.
The Big Dipper is a group of stars that are shaped like a dipper or drinking ladle. Think of it as a cup with a handle. The two stars in the end of the dipper or ladle point to Polaris.
The North Star and Navigation
Sailors at sea have been using the North Star to navigate their ships for hundreds of years. They used Polaris to determine both direction and latitude. Latitude refers to positions north or south of the Equator. It is measured in units called degrees.
The angle of Polaris above the horizon is used to measure the degree of latitude. An instrument called a sextant is used for this purpose. In the past, sailors and explorers used sextants and Polaris to figure out their latitude. Navigators on ships had to be highly skilled. They needed a lot of knowledge of math and the night sky to successfully navigate at sea.
The Underground Railroad
The North Star was also important on the Underground Railroad. The Underground Railroad consisted of routes and safe houses that slaves could use while escaping to freedom.
Slaves escaping from slave states in the South had to go north. They either went to free states in the North or to Canada using Polaris to guide them at night. Slaves were told to follow the drinking gourd. A drinking gourd is like a ladle that people used to use to drink water. This is the chorus of the song:
Follow the drinking gourd,
Follow the drinking gourd,
For the old man is awaiting for to carry you to freedom
If you follow the drinking gourd.
The Southern Cross: Crux
Polaris or the North Star is a very important star because it is often used for navigation. But Polaris is only visible in the Northern Hemisphere. There is no pole star in the Southern Hemisphere. Instead a constellation called Crux is used to mark south.
The constellation Crux is the smallest of the 88 constellations. It is commonly known as the Southern Cross. Two of the stars in Crux, Alpha and Gamma, point toward the south celestial pole. The brightest stars in Crux appear on the flags of many countries in the Southern Hemisphere, including Australia, New Zealand and Brazil.