The constellation of Cancer is the darkest of all the Zodiacal constellations, having only two stars above the 3.0 magnitude. Its brightest star is today named Beta Cancri. In human history Cancer has long been associated with amphibious creatures with exoskeletons, including turtles, scarabs and beetles. Most commonly though, Cancer has been associated with a crab and it is this form we are most familiar with today. In astrology, Cancer is one of the three water signs – which signal the transfer into a new season when the Sun begins to move through them (from our Earthly perspective).
The ancient Babylonians referred to this constellation as Mulallul and was usually depicted in temple artwork as a snapping turtle. It may have also had associations with death and the passage to the Underworld, which would explain the eventual myths that would come to surround it a few thousand years later.
The Ancient Greeks most associated Cancer with a crab that appears in the story of Heracles (more commonly known as Hercules) and his twelve labours. During his fight with the many-headed Hydra of Hades, the goddess Hera sent her pet crab Karkinos to distract the great hero by biting at his feet. Hercules crushed the crab and Hera, in an uncharacteristically altruistic move, thanked the crab for its service by sending its soul to the heavens for all eternity.
It has however been suggested by some researchers, that Karkinos may have been added to the story after its original genesis. This may have been to make the twelve labours fit with the twelve signs of the Zodiac, which would make sense as Hercules’ labours pop up often in the mythological history of the signs.
Names and Portents
Throughout a lot of recorded history, Cancer has been as a ‘dark sign’ due to its relatively low brightness compared to many other Zodiac constellations. It also shares a common etymology among most of the world’s astrological traditions. For example, in Sanskrit teachings it is known as Karkata and Roman writings often referred to it as Astacus – although in some sources was also called Litoreus.
In modern astrology, people born under the star sign of Cancer (June 22nd to July 22nd) are said to be influenced mainly by the heavenly movements of Jupiter and Neptune. In Hindu Vedic astrology, the sign is known as Karka and its most influencing astronomical body is the Moon.
21st century astronomers have learnt a lot about the patch of sky we label as Cancer, even though it is so dark. The brightest star in the constellation, Beta Cancri is an incredible 290 light years away. That’s 1,705,000,000,000,000 miles! That distance is enough to make it look relatively dim to us, even though it is a giant star that is 50 times as big as the Sun – and shines 600 times as brightly on an absolute scale.
A few stars in Cancer are known to have exoplanets orbiting them, including 55 Cancri B which scientists think may have a Super-Earth rocky planet in its habitable zone. Who knows? Maybe alien astrologers might live there, crafting their own myths about the Sun.