I skied in the woods under last night’s first quarter moon and learned something about trust. In the mix of shadow and low light, I could see the trail clearly only half the time. Along the stretches where darkness or shadow obscured the track, I kept the faith while gravity and momentum did their thing. After an hour of skiing, I’m happy to report there were no falls and only a few moments of trepidation. I learned to really open up my eyes as well as to trust what lay ahead.
A first quarter moon is only 1/10 as bright as a full moon. That doesn’t sound like much, but it’s a surprising amount of light really.
Part of the trail was lit by artificial light. After leaving this cocoon of easy navigation, the woods looks dark indeed, but within five minutes, my eyes were dark-adapted all over again. The trail grew more distinct, peeling birch bark showed shiny highlights under the moonlight, and occasional snow crystals sparkled off to sides.
Tonight the moon will have swelled a bit beyond half and shine a few percent brighter than last night. It’s high up in the south at nightfall just 2 degrees below the Seven Sisters (Pleiades) star cluster. If you block the moon with your thumb and look above and to its right, you might be able to see the cluster with your naked eye. City dwellers, for whom the Pleiades are never visible with the naked eye even under moonless skies, can use the moon as a guide to find them with binoculars.
The moon’s high position in the sky reminds us of where the sun once was … and will be again. On and around May 20, the sun will occupy the moon’s spot and remain up for hours just as the moon will tonight. Moonrise this morning was around 10:30 and it won’t set until tomorrow around 2:30 a.m.
Yesterday, Andrew Kirk of Bishop, Calif. sent me a fascinating series of photos taken near sunset showing the shadows of mountain peaks cast on dust in the air. Look at each frame closely and you’ll notice at least two things: the shadows lengthen with time, just as your shadow does near sunset, and they rotate about the sun pivoting from right to left. That’s because the sun is not only going down but also moving to the right or north at the same time.
If you watch your own shadow at sunset, it will pivot in the same way as the ones in the photo do. Most amazing is that only 8 minutes elapsed between the top and bottom images. Thanks Andrew for sharing your unique and beautiful perspective on our planet’s daily motion!