Arcturus is the brightest star in the northern celestial hemisphere. (The first three stars on this list are actually in the southern celestial sphere, though seasonally they are visible from the northern hemisphere of Earth).

Known as the Bear Watcher, Arcturus follows Ursa Major, the Great Bear, around the north celestial pole. The name itself derives from the Greek word arktos, meaning bear.

During a struggle between gravity and pressure, it has swelled to 25 times the Sun’s diameter. Eventually the outer envelope of Arcturus will be peeled away and the material ejected as a planetary nebula similar to the famed Ring Nebula in Lyra. What will be left behind is a white dwarf.

Arcturus is the Alpha (meaning brightest) star of the springtime constellation Bootes, The Herdsman. You can find it by using the Big Dipper as your celestial guidepost. Follow the arc of the handle until you come to a bright orange star. This is Arcturus, forming the point of a pattern of stars resembling a kite.

In the spring, if you keep following the arc, you’ll encounter another bright star, Spica. If this all sounds a bit confusing remember this phrase: "Arc to Arcturus, speed on to Spica."

In the 1930’s when astronomers were busy measuring the distance to nearby stars, Arcturus was believed to be 40 light-years distant. With emergent photocell technology employed at the 1933 World Fair in Chicago, the light from Arcturus was collected and used to activate a series of switches. Light believed to originate at the time of the previous Chicago World Fair -- the city had hosted it 40 years prior -- was used to illuminate and officially open the Fair in 1933.

We now know Arcturus is 37 light-years away, however.