Rev. Candace McKibben
This Sunday, May 15, more than 2.7 billion of the world’s 7.9 billion people will have an opportunity to watch the same celestial event, if the weather cooperates.
The moon will be darkened by the long, with a shadow of the earth in a total eclipse on Sunday evening and into early Monday morning. A lunar eclipse happens when the sun, earth, and moon are precisely aligned as the earth blocks the sunlight from reaching the moon.
This is safely viewed with the naked eye, though the experience is enhanced by binoculars or telescope.
Eclipses have held a fascination for humans throughout history. As early as 3,000 years ago, the Babylonians were keeping records of the movements of the celestial bodies on clay tablets, calculating the date and time of future eclipses. This data is still referenced today.
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round and wobbling
In ancient Greece, Aristotle, born 384 BCE, noted that the shadows on the moon during lunar eclipses were round, regardless of from where an observer saw them. I have realized that only if Earth was spherical would it create round shadows. This revelation was long before the first ships sailed around what some presumed was a flat earth.
Another ancient Greek, Hipparchus, the founder of Trigonometry, born in 190 BCE, made the discovery that the earth wobbles on its axis like a top about to fall over.
He compared the position of stars relative to the Sun during lunar eclipses he observed to the positions recorded hundreds of years earlier by the Babylonians and noticed that the stars were shifted in a systematic way.
His observations led to an understanding that the earth, while spherical, is not a perfect sphere but has an equatorial bulge, which causes it to wobble. This cyclic wobbling in the orientation of Earth’s axis of rotation is called precession and is so incremental it takes 25,772 years for a full precession to occur. Yet our awareness of it came from observations of lunar eclipses millennia ago.
Tracking Earth’s shadow
The ancients are not the only ones to care about what lunar eclipses teach us. Modern scientists rely on total lunar eclipses to measure astronomical distances. By looking at the curvature of the Earth’s shadow that falls on the Moon, scientists can reconstruct the relative size of the Moon versus the Earth’s shadow-cone, and geometrically reconstruct the Earth-to-Moon distance.
Solely from measuring the Earth, Moon, and Sun, humans can determine how far away the stars are.
Researchers tracking the flight behavior of the black swifts native to North America, a species in decline, outfitted seven birds with backpacks and monitoring devices. In addition to information they had expected to glean, they learned that during the total lunar eclipse of January 2019, the birds dropped in altitude during the darkness and afterwards shot up to their former altitude as if on cue.
Biologists tell us that while difficult to experimentally verify because of the changing variables of totality in lunar eclipses, lemurs, bats, mosquitoes, and spiders are among the animals observed behaving differently.
Detecting climate change
Some climate-change researchers suggest that lunar eclipses teach us about a factor in climate change. The current low level of volcanic ash in the earth’s atmosphere, based on lunar eclipse data taken since 1995, suggests increasing penetration of light during total eclipses.
This, they say, is why the moon appears ruddier and brighter as all the earth’s sunrises and sunsets filter through. Some scientists believe this atmospheric clarity may be contributing to climate change, increasing the need for humans to be even more vigilant about green gas emissions we can control, since we cannot control the level of volcanic ash.
NASA’s Lunar Reconnaissance Orbiter that has been gathering data on the moon since its launch in 2009 will also fall into the earth’s shadow this weekend, causing mission controllers to shut down most instruments to conserve energy.
The one instrument they will leave turned on is interestingly called, the Diviner. It will be recording how the moon’s surface responds to the rapid cooling the eclipse creates.
Inspiration for artists
The eclipse of the sun or moon has often been a subject of art and literature. In 1867, Thomas Hardy writes in his poem, At A Lunar Eclipse, “Thy shadow, Earth, from Pole to Central Sea, now steals along upon the Moon’s meek shine,” and wonders at the seeming serenity cast “from the troubled torn form of earth.”
Canadian Composer, Timothy Corlis, was inspired by the February 2008 lunar eclipse to write the lovely cello and piano duet, “Prelude for the Night of the Lunar Eclipse,” that can be heard at silentdawn.ca/composition/prelude-for-the -night-of-the-lunar-eclipse/
The contrast of light and darkness is an important one for people of faith and spirituality. And while we may prefer the light, I agree with Episcopal priest, Barbara Brown Taylor, who said, “I have learned things in the dark that I could have never learned in the light.” Rather than a solar spirituality, she thinks of herself having a lunar one, “in which the divine light available to me waxes and wanes with the season.”
How fascinating to think about the ways lunar eclipses teach and inspire us. As we come to this event that connects us to more than a third of the world’s population, I pray we will make the effort to go outside, look up, and contemplate the wonderful mystery of light and dark.
According to NASA, who will be live streaming the event online, the moon will enter the earth’s shadow around 10:30 pm, be fully immersed around 11:30, and fully reappear around 2 am
Perhaps as we watch the moon, we might express gratitude for the many ancient and current people who teach us about the moon’s lessons, and for the earth and all her people.
The Rev. Candace McKibben is an ordained minister and pastor of Tallahassee Fellowship.
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