Do you know the name of the brightest nighttime star we see most often? It’s not Sirius, the brightest star in the night sky that this time of year. It’s not Polaris, the North Star.
And it’s certainly not the planet Jupiter in the high southern sky at the end of twilight, or Venus that’s dazzling our southwest early evening sky.
No, the brightest star we see most often in the skies is Capella, which is an Arabic name that translates to English as “she goat.” Our bright star is a lady goat. You can easily spot Capella perched brightly in the high eastern sky near the overhead zenith.
Capella is actually two huge stars separated by a little more than 60 million miles. That’s less than the distance between Earth and the sun. Both of these stars are huge, each possibly more than 10 million miles in diameter. Astronomers believe that these two behemoth stars orbit each other every hundred days or so.
Capella is the fourth brightest star we can see throughout the course of the year and the brightest star we see most often in the northern hemisphere because it’s the closest bright star to the North Star that marks the position of the North celestial pole.
Everything we see — the sun, moon, planets and stars — appears to rotate once around Polaris at the North celestial pole every 24 hours.
Stars and constellations that are close to Polaris, like the Big and Little Dippers and the W-shaped Cassiopeia, are always above the horizon in a tight circle around the North Star. They are called circumpolar stars, and we see them night after night.
Capella, the goat star, is not quite close enough to Polaris to be considered a circumpolar star, but it’s very close. Because of its northwardly position, Capella is in our evening skies from late August until just about mid-June, and throughout the year it never goes a complete night without making a brief appearance.
Capella is also the brightest star in the constellation Auriga, the chariot driver, one of the strangest constellations in the skies. It basically looks like a lopsided pentagon with Capella at one of the corners.
There are lots of stories and mythology about how certain constellations got up in the sky, depending on the local culture. Hera, the Queen of the gods of Mount Olympus and the wife of Zeus, the king of the gods, was certainly not known for her kindness. She bore a son who was born lame and tossed him out of the heavens and sent him plummeting to Earth.
Miraculously the young lad landed wasn’t killed. A nice young couple adopted him, named him Hephaestus and raised him to be a fine young man. He wasn’t able to get around very well so he used multiple canes. In spite of that he became quite a craftsman with iron and armor.
Wanting to be able to travel, he attached wheels to a container and invented the very first horse drawn chariot.
The gods of Mount Olympus, with the exception of his awful mother Hera, were in awe of Hephaestus and placed a chariot among the stars in his honor with Hephaestus at the reins.
No one really knows for sure how Capella, the brightest star in Auriga, got to be known as a goat star, but it’s suspected that shepherds named the three faint but distinct stars that form a triangle right next to Capella “the kids,” making Capella a mama goat.
Mike Lynch is an astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book, “Washington Starwatch,” available at bookstores. Check his website, www.lynchandthestars.com.
The Everett Astronomical Society: www.everettastro.org/.