The North Star is the brightest star
Polaris, the North Star, is not the brightest star in the night sky. That distinction belongs to Sirius, which is roughly 20 times brighter than Polaris in apparent magnitude. Polaris is notable not for brightness but for its near-stationary position above Earth's North Pole.
What we know
Polaris (Alpha Ursae Minoris) lies very close to Earth's celestial north pole due to Earth's axial orientation. Because of this, it appears nearly stationary in the northern sky while other stars appear to rotate around it. This makes Polaris invaluable for navigation, which is why it is widely known as the North Star.
However, its fame for navigation has apparently led many people to assume it is also the brightest star in the sky. It is not. Polaris has an apparent magnitude of approximately 1.98, placing it as only the 48th brightest star visible to the naked eye. Sirius, the Dog Star in the constellation Canis Major, has an apparent magnitude of about -1.46 and is the brightest star in the night sky by a wide margin. Canopus is the second brightest, followed by Arcturus and Vega. Polaris does not make the top 25.
The confusion may also stem from the phrase 'as constant as the North Star', which refers to its positional stability, not its brightness. Due to the precession of Earth's axis, Polaris will not remain the pole star indefinitely. In roughly 13,000 years, the star Vega will be closer to the celestial north pole.
Common claims
- Polaris is the brightest star in the skyFalse - it is the 48th brightest
- Sirius is the brightest starTrue - apparent magnitude -1.46
- The North Star never movesAppears near-stationary but precession shifts it over millennia