by Edward Herrick-Gleason
Today we look into a warm, vibrant and lovely future: namely, into mid-May, the time of year when the nordic wind spirits finally retreat to the hinterlands and spring truly begins. This year, not only will mid-May offer us an abundance of bone-thawing warmth, we’ll also experience a total lunar eclipse! Weather permitting, we shall see the entire event here. The Southworth Planetarium will be open for this event and so we want to be sure that everybody knows about it, hence this early alert. This article will provide subscribers with a time-table specific to Portland (ME). Tomorrow’s article answers questions about the lunar eclipse: both general information and that specific to the May 2022 event.
First, the eclipse will occur on the night of May 15th. Actually, it will begin on May 15th and end on May 16th. Refer to the time table below.
May 15 – 9:32 p.m. PENUMBRAL ECLIPSE BEGINS
Earth’s shadow is divided into two regions: the light, outer part of Earth’s shadow, called the ‘penumbra,’ and the inner region called the ‘umbra.’ The penumbral eclipse begins when Earth first touches the penumbra. The moon passes completely into the penumbra before it reaches the umbra. Honestly, unless you’re one of those mystical poetic types who can actually tell the difference between a whisper of a breeze and a caressing zephyr, you won’t notice much during the penumbral part of a lunar eclipse. Perhaps the brilliant moon’s pallor is rendered a few phantoms less vibrant, but even that is a stretch.
May 15 – 10:27 p.m. PARTIAL ECLIPSE BEGINS
This is when the ‘action’ starts. The umbra is the dark interior shadow. Once the umbral eclipse begins, we’ll see Earth’s curved shadow against the moon. We’ll watch the shadow migrate across the moon until the moon is completely immersed in Earth’s shadow.
May 15 – 11:29 p.m. TOTALITY BEGINS
Totality begins when the moon is completed inside Earth’s umbra. The moon will not be wholly lost from sight. Instead it will appear reddish, because Earth’s atmosphere scatters blue light, but directs red light into its shadow. (We see a blue sky during the sky because of this effect.) The eclipsed moon will reflect this reddish light back to us, producing the ominously named ‘blood’ moon. One effect that we think is absolutely magnificent is the ‘spherical moon’ phenomenon. During totality, the color differential across the moon’s facade lends it a spherical appearance. The moon actually appears as a crimson sphere in space, as opposed to the full moon’s usual disc-like appearance.
May 16 – 12:11 a.m. MAXIMUM ECLIPSE
When the distance separating the center of the shadow and the moon’s center is at a minimum.
May 16 – 12:53 a.m. TOTALITY ENDS
At this moment, the moon starts its exit from the umbra. We will see a thin sliver of the moon emerging from the inner shadow.
May 16 – 1:55 a.m. UMBRAL ECLIPSE ENDS
For all intents and purposes, the show is now over. The moon completely leaves the umbra and appears, well, like a full moon again, except that it remains immersed in the penumbra.
May 16 – 2:50 a.m. PENUMBRAL ECLIPSE ENDS
The eclipse event is now technically over. Of course, the moon’s brightness is hardly diminished during this last hour because the penumbra is so faint.
A few reader questions:
EVERY LUNAR ECLIPSE IS ASSOCIATED WITH A SOLAR ECLIPSE THAT OCCURS EITHER AFTER OR BEFORE IT. WHEN WILL THAT ECLIPSE HAPPEN AND WILL WE SEE ANY OF IT?
A partial solar eclipse will occur on April 30th. Unfortunately, it will only be visible in the southern hemisphere: South America and Antarctica.
WILL ANY OTHER LUNAR ECLIPSE OCCUR THIS YEAR? IF SO, WILL WE SEE IT?
Yes, another total lunar eclipse will occur on November 8, 2022. We will see the first half of this eclipse. Totality begins at 5:16 a.m. and ends at 6:41 a.m. However, in Portland, the moon will set at 6:32 a.m. Although the moon shall remain above the horizon for most of the totality period, it will be exceedingly difficult to see owing to its low position along the horizon.
WILL ECLIPSES EVER STOP BECAUSE OF THE MOON’S RECESSION FROM EARTH?
The moon is moving away from Earth at the rate of 3 -4 cm per year. However, Earth’s shadow extends about 840,000 miles into space and the moon’s distance from Earth, which currently can’t exceed about 252,000 miles, will only increase to about 325,000 miles by the time the Sun expands into the red giant stage. Consequently, lunar eclipses will continue as long as the Sun continues to shine.
NO OFFENSE, BUT WHY SHOULD WE CARE ABOUT THIS ECLIPSE?
I find this question, which I’ve been asked many times, fascinating. The short answer is, well, you shouldn’t have to care about it at all. You are under no obligation to be interested in astronomical matters. In fact, many people lead rich, wonderful lives without giving more than a passing glance at the night sky. (Of course, in the modern day, the night sky is wholly obscured for many.) On the other hand, to watch an eclipse is to observe the interplay of worlds: a satellite that has been revolving around our planet for nearly four billion years will be moving through a shadow it has entered more than a billion times in the past and will continue to do more than a billion times in the future. The vast majority of those passages have gone unnoticed. Now, by virtue of the complex cosmos contained within our heads, we can watch, study and predict these eclipse motions. We care because through us the Universe becomes introspective and, ultimately, admires itself.
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