What three rare astronomical events occurred on March 20, 2015?

As a solar eclipse plunged many parts of the earth into darkness on Friday, March 20, 2015, two other rare if less spectacular astronomical events also took place. There was a Supermoon and a spring equinox.

A Supermoon, or perigee moon, happens when the full or new moon does its closest fly-by of the Earth, making it look bigger than it normally does. And, the spring equinox refers to the time of the year when the day and night are of equal duration, mid-way between the longest and shortest days.

First, specifically with a solar eclipse, it refers to a phenomenon where the sun and moon line up, so that the latter obscures the former. And, while it won’t be affected by either a Supermoon or a spring equinox (two other celestial events), it is rare that the three events happen at the same time.

Next, pointedly looking at the Supermoon, it was one of six that occurred in 2015. On March 20, the day of the eclipse and equinox, it appeared. Others happened in August, September and October 2015. Because the moon was new rather than full, it was not seen. But, it did go past the earth closer than ever, and its shadow was visible as it blocked out the sun that Friday morning.

Lastly, an equinox did happen on March 20. The Earth’s axis was perpendicular to the sun’s rays, an event which only happens twice a year, at the two equinoxes. After that, the earth starts to tip over, making the days longer in the northern hemisphere.