Last night's clear sky and warm temperatures in the mid-30s put the smell of bog back into the air. You forget how much you miss night fragrances until you've been without for months. March is slowly nudging out winter. You can see the signs on Earth and in the heavens. Constellations like Orion and Taurus begin the night ascendant but tip westward by 9 o'clock. Looking east, the Big Dipper rises higher and higher like a released balloon. Far below the Dipper's handle, a brand new star, Arcturus, sparks and sputters between bare branches.
I'm in love with the seasons and their many manifestations. That includes obscure things like the angle the sun's path makes to the western horizon. This path, called the ecliptic, is the same one the planets follow as they orbit the sun. In early spring, the ecliptic meets the western horizon at a steep angle — almost straight up and down. Every time you look at a planet, the sun or the moon, you're gazing across the flat plane of the solar system, defined by the ecliptic.
Dust from vaporizing comet ice and debris from colliding asteroids concentrates in that plane and glows in sunlight to create a tapering cone of light centered on the ecliptic called the zodiacal light. It's easiest to see in the evening sky during March and April, when the ecliptic's steep angle in the western sky tilts the cone into good view far from the horizon haze.
The zodiacal light is gigantic, spanning more than 50° in altitude (five fists!) from the horizon all the way up to the Pleiades star cluster. Along the way, it tapers from about 15-20° at its base, where it's brightest, to 3-4° at its faint apex. In texture and brightness it resembles the winter Milky Way. To see it you'll need a dark western sky. The best time to look is from 90 minutes to 2 hours after sunset now through March 14. Starting the 15th, glare from the returning moon will temporarily erase the delicate sight from view.
Last night it towered faintly above me and the muddy road, random dust fashioned into a sleek finger by sunlight. Turning to face north, I looked for signs of aurora but saw none. Just to make sure, I took a time exposure, and an old friend showed up in the frame — the Andromeda Galaxy.
Stop for a moment to think how much space this image encompasses. The galaxy is 2.5 million light years distant. The light we see is an equal number of years old, while the tree is a mere 50 yards away and sprouted fewer than 100 years ago. You can almost feel the vastness of time and space that separates them. And yet there they are together, side by side, linked by the dynamo of nature's incessant inventiveness.
I recently wrote about seeing the asteroid Vesta in binoculars. I hope you've had the chance to spot it. If not, there's still plenty of time. Now shining brightest at magnitude 6.1, it's faintly visible with the naked-eye from a dark sky. Using averted vision, a technique of looking askance at an object instead of staring directly at it, I succeeded in finding the asteroid without optical aid. I've included both maps again if you'd like to try.
Facing northeast to look at the Big Dipper, I noticed a spark of light at the bottom edge of my vision. Way down in the treetops, Arcturus, the 4th brightest nighttime star, twinkled in the unsteady air. This orange giant is some 25 times the diameter of the sun and located 37 light years from Earth. If there were ever a celestial herald of spring in the northern hemisphere this is it. Just like the season, Arcturus patiently waits at the perimeter of winter, ready for launch. Me, too.
One last reminder. The waning crescent moon will join Saturn, Jupiter and Mercury starting about an hour to 45 minutes before sunrise on March 9. Find a place with a wide-open view facing southeast and bring binoculars to help you find the planets more easily.
"Astro" Bob King is a freelance writer for the Duluth News Tribune. Read more of his work at duluthnewstribune.com/astrobob.