March always marks the beginning of spring for the northern hemisphere. That will happen on March 20 at 7:21 p.m. That is also called the vernal equinox, when the sun on the ecliptic crosses over the celestial equator on an upward path.

There are only two days each year when the sun rises due east and sets due west: the vernal equinox and the autumnal equinox. That is true for everyone on Earth, except for the poles. The days and nights also will be of equal length within a couple of days of the equinoxes. Those two days serve as a unifying influence that will help people on Earth gain a better sense of the planet’s motion around the sun within our solar system.

Additional Photos

This chart represents the sky as it appears over Maine during March. The stars are shown as they appear at 9:30 p.m. early in the month, at 9:30 p.m. at midmonth and at 8:30 p.m. at month’s end. Saturn is shown in its midmonth position. To use the map, hold it vertically and turn it so that the direction you are facing is at the bottom. Sky chart prepared by George Ayers

After that day, the northern hemisphere will be tilting a little more toward the sun each day as the days get longer than the nights, until we reach the summer solstice on June 21. Now that the sun is noticeably higher in the sky and the nights begin to warm a little, try to get out under the night sky more often to better appreciate its subtle beauty and power.

This is the best time of year to see the zodiacal light in the western sky just after twilight ends. This ephemeral glow will appear as a very faint, hazy cone of light tilted at an angle and extending about 10 degrees, or one fist at arm’s length, into the sky. It is so subtle that it can only be seen with no moon in the sky and far away from any source of light pollution. The only other time to see it is just before dawn in November, when the angle of the ecliptic to the horizon is at its steepest.

The zodiacal light becomes visible as sunlight is scattered off space dust in the plane of the ecliptic and reflected back to our eyes. This dust occupies a lens-shaped volume of space centered on the sun and extending well beyond the earth. This dust actually forms a band of uniform brightness all the way around the sky but can only be seen near the horizon, where it scatters more sunlight back to us on Earth in our limited field of view.

The individual particles in this vast interplanetary dust cloud are surprisingly far apart. On the average, there is only one 1mm particle about every 5 miles in this cloud. They are created by comets as they lose material while orbiting the sun and by collisions between asteroids. The individual particles slowly spiral into the sun, but they are continually replaced by new comet dust and asteroid collisions. Viewing this amazing phenomenon of nature, or even knowing about it, reminds us that we are constantly surrounded by primordial records of our solar system’s ancient creation 4.6 billion years ago.

We will lose Jupiter out of our evening sky by the end of March. The king of the planets begins the month by setting about two hours after sunset. Watch for a close conjunction of Mercury and Jupiter during the middle of the month low in the western sky 40 minutes after sunset. The pair will be at their closest, just 2 degrees apart, on March 15.

They will be visible for most of the month. Mercury is the fainter one and begins to the right and below Jupiter, catches up with Jupiter on the 15th and then continues to the right and above Jupiter. Mercury will make its best appearance for the year in March. By coincidence, both of these planets will also reach perihelion, their closest approach to the sun, within a couple of days of when they are closest to each other from our perspective. Jupiter only reaches this point once every 12 years since it takes that long to orbit the sun. Mercury, known as the swift one or the messenger, is our fastest-moving planet at 30 miles per second. It also has the least distance to travel, so one year on this little planet only lasts 88 days. Strangely, it rotates so slowly that one day lasts 59 earth days.

Just as we lose Jupiter in the west, Saturn will be at its best, rising in the east at sunset. The ringed planet now rises more than two hours after sunset, but it will rise two hours earlier, which is four minutes per day, by the end of the month.

Venus is still visible in the morning sky, but it is sinking lower and rising less than two hours before sunrise. Watch for a slender waning crescent moon to pass close to Venus low in the east-southeastern sky 40 minutes before sunrise on March 1 and again on March 31.

Neptune will be visible in a telescope just half a degree west of Venus on the morning of the 27th. Neptune is 60,000 times fainter than brilliant Venus. Our sister planet is slowly getting smaller and fainter in the sky even as it is getting more illuminated by the sun. It is now similar to a waxing gibbous moon.

March 1: The thin waning crescent moon will be just to the left of Venus this morning.

March 4: New moon is at 3:46 p.m. Giovanni Schiaparelli, one of the greatest observers of his day, was born on this day in 1835. He contributed to our early knowledge of Mars and Mercury.

March 6: Joseph Fraunhofer was born on this day in 1787. He was a German optician who made the world’s finest optical glass. He invented the spectroscope in 1814 and discovered 574 dark lines in the solar spectrum. There were later shown to be atomic absorption lines. Jupiter will be just to the left of a thin waxing crescent moon 20 minutes after sunset in the western sky. Vega 1 made a close approach to Halley’s Comet on this day in 1986.

March 12: First quarter moon is at 6:45 p.m.

March 13: William Herschel discovered the planet Uranus on this day in 1781, effectively doubling the size of our solar system since Saturn was the last planet known before then. Percival Lowell was born on this day in 1855. He thought that Mars had canals and life. Daylight-saving time begins at 2 a.m.

March 14: Albert Einstein was born on this day in 1879. He developed the General Theory of Relativity in 1915. It equated all matter to energy and redefined gravity itself as simply the curvature or topography of the fourth dimensional space-time continuum. As the physicist John Wheeler, who first proposed the concept of black holes, said, “Matter tells Space-time how to curve and Space-time tells matter how to move.” We only orbit the sun because it has a much deeper gravity well, or a more curved space-time field around it than any of the planets. This proves how everything in the universe is connected through the fourth dimension.

March 19: Full moon is at 2:10 p.m. This is also known as the Lenten, Sap or Crow moon.

March 20: Spring begins in the Northern Hemisphere at the equinox at 7:21 p.m.

March 23: The first photograph of the moon was made on this day in 1840.

March 26: Last quarter moon is at 8:07 a.m.

Bernie Reim of Wells is co-director of the Astronomical Society of Northern New England.

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