Looking to the North’s Skies
Opinion Advocates for ideas and draws conclusions based on the author/producer’s interpretation of facts and data.
by Scott Levine
When we were together last month, we found Jupiter and Venus in the western dusk. Let’s head out again, but this time, look to the north’s skies.
Maybe you’ve noticed most of the night’s familiar star patterns are only visible for part of the year. Orion, for example, arrives in the east just as the leaves start to gather at our feet. Over time, it marches across the sky until one day we notice that it’s vanished into a long, mid-spring sunset.
Things are different in the sky’s far north. Stars there don’t come and go like the others. They move as though they’re circling Polaris, the north star. They’re with us night after night, year after year.
In the mid-evenings as March ends, we’ll see our old friend, the Big Dipper, hanging from the northeast sky. It sits almost like a question mark, asking us something far too big to imagine. These stars are the most recognizable pattern within the much bigger constellation Ursa Major: the Great Bear.
Let’s keep an eye on the Dipper’s handle, which also represents the Bear’s tail. Soon after sundown, it points to our neighbors’ rooftops. As the evenings deepen, we’ll see the whole Dipper turn counterclockwise, with the handle rising into the night. As it does, we can follow the handle’s curve to one of my favorite stars.
Arcturus is the second brightest star we can see in Westchester’s nights, behind Sirius, which we talked about a couple months back. From 35 light years away, we see it as unmistakably red, like the light on a far-off buoy, guiding us through whatever messes we find ourselves in during the middle part of the year.
Like anything else, all stars are different. They grow and change, albeit much more slowly than Earth’s life does. Arcturus is an old curmudgeon, nearing the end of its life. It’s used up most of its hydrogen fuel and has swollen and cooled. It’s the type of star that our Sun will be in billions of years, when it, too, uses up its hydrogen. So, in a way, when we look up at Arcturus tonight, we’re looking at our own future.
Arcturus’s name comes to us from the Greek words for “Guardian of the bear,” which is a reference from mythology that brings us back to where we started: Ursa Major. With the Great Bear in the north’s sky every night of the year, this name carries with it the same linguistic root that gave us the word “Arctic,” meaning northern.
Each night stars rise four minutes earlier than the night before. Little by little, as these minutes add up and we move through the spring and into summer, we’ll see Arcturus travel the sky with the bear. As Ursa Major rotates toward the west, Arcturus follows just beyond its tail; the two guiding each other, and us, through the night.
Arcturus will be with us until the fall, when it, like so many other stars, disappears into the dusk. Until then, let’s keep an eye on it, and watch the story play out again and again.
Happy holidays, no matter what you’re celebrating this month, and clear skies!
Scott Levine (astroscott@yahoo.com) is an astronomy writer and speaker from Croton-on-Hudson. He is also a member of Westchester Amateur Astronomers, a group dedicated to astronomy outreach in our area. For information about the club including membership, newsletters, upcoming meetings and lectures at Pace University and star parties at Ward Pound Ridge Reservation, visit www.westchesterastronomers.org.
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