Spring begins with heavy celestial congestion
Winter is over with next Thursday night, March 19, at 10:49 p.m. — at least astronomically. That is the exact moment of the vernal equinox, the astronomical beginning of spring. When you were young you were probably taught that on the first day of spring, the days and nights are equal, 12 hours apiece, and from that day on days become longer than nights. Well, that’s just not true. Days actually become longer than nights every year on St. Patrick’s Day! I want to think it’s because of the luck of the Irish, but it’s astronomical refraction that does it.
The Earth’s atmospheric shell bends the incoming rays of the sun in such a way that the sun seems higher in the sky than it actually is. This bending is more severe near the horizon since the atmospheric layer is thicker from our vantage point. The bending of the sun’s light is so extreme near the horizon that when the sun is actually below the horizon it still appears to us to be above the horizon. If our Earth didn’t have an atmosphere, we would indeed have equal days and nights on both the spring and fall equinox dates. Astronomical refraction, however, makes sunrises earlier than they should be and sunsets later, making for a longer day.
One more myth I want to dispel about the vernal equinox involves eggs. You may have heard that it’s easier to balance an egg on end during the equinox because of the sun shining directly over the equator. That’s a complete fairy tale. Your chances of balancing an egg on end are the same every day of the year!
Even though winter is ending officially on Thursday night the evening sky will still be congested with the great winter constellations like Orion and others for some time to come. What I want to tell you about today is the congestion going on currently in the low southeast sky near the horizon in the early mornings, about a half-hour to 45 minutes before sunrise.
If you put yourself in a place with an unobstructed view of the southeast horizon you should be able to see four fellow planets in our solar system lined up in nearly a straight line. From the upper right to the lower left, you can see Mars, Jupiter, and Saturn bunched up tightly together with Mercury separated from them a bit to the lower left, very close to the horizon. All four planets are easily visible with the naked eye, but they’ll appear super fuzzy through a telescope because of the thicker air near the horizon. You really don’t need a scope to enjoy the show anyway, and what a show it will be!
On Wednesday morning, March 18, the waning crescent moon joins the line of planets. On that morning the moon, Mars, and Jupiter will all be extremely close together, forming an exceptionally tight triangle. It will be quite a sight! You should be able to easily fit all three of them in the same field with a pair of binoculars.
On Thursday morning, March 19, the thinner waning crescent moon will be parked just to the lower left of Saturn. On March 20, Mars and Jupiter will pass within one degree of each other. Now that’s a really close celestial hugging!
On Saturday morning, March 21, Mercury will be joined by an extremely faint and thin waning crescent moon just below and to the right of the planet named after the messenger of the gods.
There’s a lot of moving parts in the early morning this coming week! Pray for clear early mornings!
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is also the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and at adventurepublications.net. Contact Mike Lynch at email@example.com.