Everyone knows the sun is the brightest star in the sky, but what is the second brightest star in the Everett sky?
Did you say the North Star, Polaris? Don’t feel bad … you’re only off by about 40 stars. There are at least that many other stars in the night sky brighter than Polaris.
The correct answer is the star Sirius, the bright shiner at the nose of the winter constellation Canis Major or the Big Dog.
To locate Polaris in the sky this time of year look for the Big Dipper high in the northern sky. If you’re facing north it’ll appear nearly upside down. Draw a line in your mind’s eye between the stars Merak and Dubhe on the side of the pot opposite the Big Dipper’s handle. Continue that imaginary line downward and you’ll run right into Polaris.
Though not the brightest, the North Star is still a very significant star. I call it the “lynchpin of the heavens” because every celestial object in the sky, even the moon and the sun, circle Polaris every 24 hours.
Polaris is anchored about halfway from the northern horizon to the overhead zenith because it shines almost directly across the North Pole. We certainly can’t feel Earth’s rotation, so the only real physical evidence we have that our world is rotating is by watching Polaris.
Constellations really close to the North Star like the Big and Little Bear, Cassiopeia the Queen and Cepheus the King always stay above the horizon as they parade around Polaris. We call these circumpolar stars. If you travel farther north in Canada the North Star would be higher in the northern sky, and you would see more circumpolar stars.
If you travel into the southern U.S. and into Mexico, Polaris would be fixed lower in the northern sky and you’d see fewer circumpolar stars.
All the other stars we see in our night sky that are not circumpolar are referred to as diurnal stars. They too are circling around the North Star every 24 hours, but their circles are a lot larger, so much so that the northern portion of their loop is below our northern horizon.
Strictly from our visual perspective these stars rise at some point above the eastern horizon and set in the west, just like the sun and moon. The night sky is not static. It’s always on the move. Don’t like what you see in the heavens for stars? Just wait and you’ll see new shiners rising in the East. You can easily observe these changes within a couple of hours.
Every 24 hours every star in the sky shifts slightly to the west by 1 degree or the width of two full moons. You can prove this by lining up a fairly bright star that’s low in the sky directly above a prominent structure such as a church steeple or a flag pole.
Mark or remember where you’re standing and make a note of the time, at least down to the minute. On the next clear night stand at the same spot at the same time and you should easily see that the star has shifted a tiny bit to the west.
After just a few weeks you’ll really see the seasonal shift. Constellations in the western sky will sink off the celestial stage and new constellations will be on the rise about four minutes earlier each evening.
That’s why there are different constellations in different seasons, but there can be more than one set of seasonal constellations in the sky at a time. For instance right now we still have a few winter constellations like Gemini the Twins and Auriga the Chariot Driver in the low western sky in the evening. In the low eastern sky summer constellations like Cygnus the Swan and Lyra the Harp are on the rise. In between we’re enjoying spring star patterns like Leo the Lion.
The North Star should really be called “north stars” because Polaris, like most of the stars you see at glance, is actually three stars. There’s the large part of the triplet that you see with the naked eye, and there are two smaller stars as well that you need a high-powered telescope to detect. All three stars orbit each other almost 2,500 trillion miles away.
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 and at his Web site www.lynchandthestars.com.
The Everett Astronomical Society welcomes new members. Go to www.everettastro.org/.
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