An eclipse is just one part of a big event
The events of April 8 show solar eclipses are special to us.
It is not just a matter of the comparatively rare event of the moon passing in front of the sun. For many, the spectacle makes us feel part of something immensely bigger, which is beyond our control.
Our fascination with solar eclipses is probably as old as humanity. Long before Isaac Newton, Johannes Kepler and others who made it possible for us to precisely analyze the orbits of objects in space, our ancestors studied the rhythms of the heavens and could predict solar eclipses with great accuracy. Woe betide the astronomer who failed to predict one.
We have a situation that must be extremely rare in the universe. From Earth, the Moon looks as big in the sky as the Sun, making it possible to cover the bright solar disc completely, revealing the pink loops and other structures in the solar chromosphere, and the pale streamers of the solar corona. There is a down side. As the moon interacts with our oceans, making the tides, the force of our oceans on the moon is making it gradually move further out into space. One day it will appear too small to cover the solar disc, bringing our current magical era to an end.
Some years ago, I was in the U.K. during an eclipse. I had no scientific plans for the eclipse, and just planned to enjoy the spectacle and feel the awe.
However, the weather forecasts were horrible. Devon in Southwest England, where I was, was headed for several days of heavy cloud and intermittent rain. One wry joke about Devon is “Welcome to Devon, where it rains eight days out of seven.”
On the other hand Sussex was to be clear, cloudless and sunny. I decided that a marginal eclipse in Sussex would be better than standing watching the clouds get darker as the rain ran down my neck. So we elected to set up some equipment for safe solar observations in the backyard in Sussex, with a picnic and bottle of wine to toast the sun.
Eclipse day in Sussex dawned sunny with a cloudless sky. At the predicted time the solar disc showed a dark nibble, the edge of the moon. It slowly got bigger, and as more of the disc was covered, it got darker. However, our eyes are highly adaptable and so the main effect was finding colours harder to see and it getting harder for our eyes to focus. Eventually, the entire solar disc was covered apart from an incredibly thin, thread-like crescent, with darker gaps where the light was blocked by lunar mountains.
When experiencing eclipses it is important not only to watch the sun; we need to watch our surroundings. When the solar disc was covered but for that thin thread of light, the trees all looked odd, showing sparkly patterns that shifted in the wind. The ground was covered with crescents of all sizes, moving, appearing and vanishing. Gaps between the leaves on the trees were acting as pinhole cameras, projecting images of that solar crescent on each other and on the ground beneath. Then the crescent broadened as the moon moved on, and our surroundings started to brighten again.
We must have had just a bare instant of totality, but the experience was one I will never forget. Eclipses offer not only opportunities for scientific research into how the sun works and how it interacts with the Earth, but also into the fascinating issue of how we respond to eclipses.
—————
Venus lies extremely low in the dawn glow. Jupiter shines very low in the west after sunset. The moon will be full on Tuesday.