Polaris: The North Star

Contributor: Lindsey Congalosi. Lesson ID: 13118

If you were lost at night, could you use the stars to find your way? Learn how you can use the North Star to navigate, determine your latitude, predict star movement, and more!

categories

Earth Science, World

subject
Science
learning style
Visual
personality style
Golden Retriever
Grade Level
Middle School (6-8), High School (9-12)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

Audio: Image - Button Play
Image - Lession Started Image - Button Start

Before GPS was created, humans had to use the stars to find their way at night. Polaris is known as the North Star because it can be used to easily find which direction is north.

  • Could you find Polaris in the sky and use it to navigate your way if you were lost at night?

Read on to learn how!

If you walk toward Polaris' location in the sky, you are traveling north because Polaris is located directly above the Celestial North Pole.

Picture the earth's axis, which is the imaginary line around which the earth rotates.

earth's rotation around its axis

The axis of the earth points directly at Polaris. In other words, if you were to extend the axis for roughly 433 light-years, you would eventually run into Polaris.

Because of its position, Polaris can be visible in the same place in the night sky at any time of night and during all seasons.

  • Have you ever watched the movement of the stars at night?

Although the stars are actually fixed in the universe, they appear to move slowly across the sky because the earth is moving. This motion is best seen in a time-lapse video.

See if you can identify the location of the North Star while watching this video.

Image - Video

  • Did you guess that Polaris is the center?

The location of Polaris causes all the other stars to appear to rotate around it as Polaris appears to remain motionless.

Polaris time-lapse photo

Polaris is only visible from the Northern Hemisphere. There is no South Star.

The star Sigma Octans is close but is just over one degree away from the South Celestial Pole. One degree might not sound like much, but when you are talking about the enormity of space, that one degree can make a big difference.

Locating Polaris

Polaris is not the brightest star in the sky, but it is the brightest star in the constellation Ursa Minor, also known as the Little Bear or Little Dipper.

Polaris can be found at the tip of the handle of the Little Dipper. However, the other stars in the Little Dipper are very faint and can be blocked out by a small amount of light pollution or even the light of a bright moon.

An easier way to locate Polaris on these nights is to use the Big Dipper, whose stars are much brighter.

Start by facing the north half of the sky. Try to find the Big Dipper, also known as Ursa Major, which looks like this.

Ursa Major

Locate the two stars that make up the end of the ladle, Dubhe and Merak, also called the Pointer Stars.

Pointer Stars

Draw a line between these two stars and then extend the line roughly five times away from the dipper. Polaris will be very close to this point and is the brightest star in that section of the sky.

locating Polaris

To review, watch the video below.

Image - Video

Another fact that helps locate the North Star is that the altitude of Polaris is the same as your latitude on earth.

Remember that latitude refers to your distance from the equator. Lines of latitude run parallel to the equator, as seen below. The highest measure of latitude is 90°, found at the North and South Poles.

latitudes

Altitude here is slightly different than our usual definition, which is the height above sea level. The altitude of Polaris refers to the angle at which we see it.

The horizon, the line where the land appears to meet the sky, is used as the bottom of our angle while Polaris is the top.

altitude of Polaris

Watch the following video on how to use the stars to determine latitude.

Image - Video

Move on to the Got It? section to explore Polaris further.

Image - Button Next

Elephango's Philosophy

We help prepare learners for a future that cannot yet be defined. They must be ready for change, willing to learn and able to think critically. Elephango is designed to create lifelong learners who are ready for that rapidly changing future.