This is an artist's depiction of Polaris in the constellation Ursa Minor.
Click on image for full size
NASA, ESA, G. Bacon (STScI)
Polaris is Big!
News story originally written on June 14, 2000
Scientists using a new telescope have calculated the actual size of the North Star, otherwise known as Polaris. It turns out that Polaris is 46 times larger than the Sun. It is no surprise to scientists, because Polaris is a cepheid star.
Cepheids are special stars that pulsate at a constant period. In other words, cepheids get brighter for a short time because there size changes. The complex make-up of the stars creates this effect. Cepheids are known to be much larger than normal stars like the Sun.
Polaris is one of the most famous stars in our night sky. The North Star is almost directly above the Earth's North Pole, so the position of the star changes only slightly during the year. Sailors used Polaris to guide them on the open seas. Today we know Polaris as the last star in the constellation Ursa Minor, or the Little Bear.
Shop Windows to the Universe Science Store!
Our online store
on science education, classroom activities in The Earth Scientist
specimens, and educational games
You might also be interested in:
It was another exciting and frustrating year for the space science program. It seemed that every step forward led to one backwards. Either way, NASA led the way to a great century of discovery. Unfortunately,...more
The Space Shuttle Discovery lifted off from Kennedy Space Center at 2:19 p.m. EST, October 29th. The sky was clear and the weather was great as Discovery took 8 1/2 minutes to reach orbit for the Unitied...more
A moon was discovered orbiting the asteroid, Eugenia. This is only the second time in history that a satellite has been seen circling an asteroid. A special mirror allowed scientists to find the moon...more
Will Russia ever put the service module for the International Space Station in space? NASA officials are demanding an answer from the Russian government. The necessary service module is currently waiting...more
During a period of about two days in early May, 1998, the ACE spacecraft was immersed in plasma associated with a coronal mass ejection (CME). The SWICS instrument on ACE, which determines unambiguously...more
J.S. Maini of the Canadian Forest Service has referred to forests as the "heart and lungs of the world." Forests reduce soil erosion, maintain water quality, contribute to atmospheric humidity and cloud...more
In late April through mid-May 2002, all five naked-eye planets are visible simultaneously in the night sky! This is includes Mercury which is generally very hard to see because of its proximity to the...more