North star

North Star (or Polaris) is a star that has been used for navigation and guidance for many centuries due to its consistent position in the sky. It is the brightest star in the constellation of Ursa Minor and is located very close to the north celestial pole, making it the current northern pole star.

History

The North Star has been used for navigation since Antiquity, due to its consistent position in the sky. Ancient mariners and explorers, such as the Vikings, used the North Star to navigate their way across the oceans. The star's name, Polaris, comes from the Latin word 'polaris', meaning 'pole star'.

Characteristics

The North Star is a yellow-white supergiant and spectral type F7Ib. It is located at a distance of about 433 light-years (133 parsecs) from Earth. Despite being the North Star, it is not the brightest star in the night sky. That title belongs to the star Sirius. However, Polaris is a Cepheid variable star, meaning it pulsates in brightness.

Role in Navigation

The North Star's position near the north celestial pole means that it appears almost motionless in the sky, and all the stars of the Northern sky appear to rotate around it. Therefore, it can be used to determine the direction of north and the latitude of an observer on Earth.

Future of the North Star

Due to the precession of the Earth's axis, the position of the North Star will change over time. In about 13,000 years, the star Vega in the constellation Lyra will be the North Star.

See also

• Star
• Constellation
• Ursa Minor
• Navigation
• Celestial navigation