In March, we observe the Vernal (Spring) Equinox. "Nox" implies "Night" and the prefix "Equi" means 'equal.' Thus -- the Spring Equinox is one of two days of the year when the day and the night are equal in length. The Vernal Equinox this year occurs at 6:27 a.m. EDT on March 20. Spring will have sprung although, by the look of the daffodils well sprouted in my front yard, spring has already begun! I have lived in Northwest Arkansas for about 22 years and this is the warmest winter I have ever experienced here!
Of course, we can expect rain in March because now begins a bit of a Monsoon season at this latitude. Nevertheless, the percent of clear nights, good for observing the night sky, will increase. Yippee for we amateur astronomers! One can only go out in one's garage and buff one's equipment for just so long -- I want to use my astronomy stuff!
If you get up before sunrise, you can see Jupiter and Saturn well placed for observing. If you want to find these huge planets on a given morning, type something like: Jupiter's position in the night sky on (the date) into your Internet browser. Jupiter is quite bright and is easy -- Saturn is more difficult and will take a sky map to locate it.
Venus is that very bright object in the southwest after sunset. It is about as high in the sky as it gets in the northern hemisphere. There is an interesting historical episode I remember as I gaze at Venus. From about Aristotle's time until 1610, authorities and ordinary folk as well, believed that the Earth was at the center of the solar system and that the Sun and the planets revolved around Earth. (Aristarchus, circa 230 B.C., believed the Earth rotated around the Sun and was not the center of the solar system.) They also believed that the planets and the Sun were all at the same distance and revolved around the Earth sort of as if they were placed on the hub of a revolving wheel. However, in 1610, Galileo used his homemade telescope to observe Venus. He noticed that Venus has phases, rather like the Moon. He reasoned, correctly, that the only way Venus could have phases was if Venus were closer to the Sun than Earth is. When he looked at Jupiter, he never saw phases at all and, again reasoning correctly, concluded that Jupiter must be further from the Sun than the Earth is from the Sun. While these discoveries did not conclusively prove the Earth rotates around the Sun each year, it did show that it was very unlikely that Venus and Jupiter were equidistant from us. Little by little, it became impossible to believe that the Earth is the center of the solar system.
About this time of year, a rare observation can be made if the conditions are just right. The inner solar system is dusty. When the Earth and Sun are lined up just right, one can sometimes see counter-shine or Zodiacal Light. Zodiacal Light occurs because as the Sun sets, the Sun's light reflects from tiny dust particles scattered in the inner solar system. I have seen Zodiacal Light once under very dark sky conditions in California. A friend of mine and I had gotten the car we were in bogged down in mud as we drove home from a night under the stars. We had to hike to get a tow (cell phones had not been invented) and at first, we thought we were seeing the Milky Way. It was dimmer than the Milky Way though, and it was like a pillar of light coming up from the horizon -- not a continuous band of stars crossing almost all of the night sky as the Milky Way does. I have never seen it since but you might be lucky enough to see it this spring season if you are under very dark country skies. And...stay out of the mud!
I count the days now until Aug. 21 when there will be a total eclipse of the Sun that will cross just north of the middle of the USA. I am lining up my equipment now, choosing what telescope to take, planning a trip to eastern Oregon where conditions, I hope, will be just right.
Get out and look at the night sky -- a great free show!
-- Dr. David Cater is a former faculty member of JBU. Email him at [email protected]. The opinions expressed are those of the author.
Community on 03/01/2017