Cetus: The Sea Monster

If you want to find a sea monster, you don’t need to take submarine down into the inky depths of the ocean. All you have to do is look up into the night sky and find the constellation Cetus.

by Jaime McLeod Updated: December 5, 2020

If you want to find a sea monster, you don’t need to take submarine down into the inky depths of the ocean. All you have to do is look up into the night sky and find the constellation Cetus.

Bordered by Aries, Pisces, Aquarius, Sculptor, Fornax, Eridanus, and Taurus, Cetus the sea monster was one of 48 constellations cataloged by the Second Century Greek astronomer Ptolemy, and is still one of 88 officially recognized modern constellations. Cetus sits in a region of the sky called “the sea,” which is home many water-related constellations.

Cetus contains 88 stars, 15 of which make up its shape, said to be a massive creature similar in appearance to a whale. In fact, modern viewers often refer to the constellation as “the whale.”

The brightest star in Cetus is Beta Ceti, also called Deneb Kaitos, meaning “the whale’s tail.” The orange-hued giant sits 96 light-years from Earth. After that is the red giant Alpha Ceti, traditionally known as Menkar. It forms double star system with 93 Ceti, a less brilliant blue-white star. Other visible stars include Gamma Ceti and Tau Ceti, the latter of which is notable for being the closest known Sun-like star, at a distance of 11.9 light-years from us.

The constellation’s most famous star is probably Omicron Ceti, more commonly known as Mira, which was the first variable star ever discovered. Over a period of 332 days, the star varies between shining brightly at a magnitude of 3 and fading until it becomes invisible to the naked eye. This unending magic show is the reason for its name, Mira, which means “the amazing one.”

Cetus is not one of the 12 constellations in the traditional Zodiac, but the planets do briefly pass through it in their journey through the night sky. The constellation also plays host to many asteroids at various times of the year.

In addition, because the constellation sits far enough away from the band of the obscuring dust of the Milky Way, many distant galaxies can be seen within it. The brightest of these is the Messier Object M-77, a spiral galaxy which sits near the star Delta Ceti. Another popular deep sky object is the planetary nebula NGC 246, also called the Cetus Ring. Its distinctive shape has earned it the nickname “the Pac-Man Nebula” among some sky watchers.

In Greek Mythology, Cetus was a sea-monster slain by the hero Perseus. The sea god Poseidon unleashed the monster on Ethiopia after Queen Cassiopeia boasted that her daughter Andromeda was more beautiful than the Nereids, and Andromeda was chained to a rock as a sacrifice. Persus killed the monster in order to claim Andromeda as his bride.

Jaime McLeod

Jaime McLeod is a longtime journalist who has written for a wide variety of newspapers, magazines, and websites, including MTV.com. She enjoys the outdoors, growing and eating organic food, and is interested in all aspects of natural wellness.