It is only 5 p.m., but it feels like I should be getting ready for bed. I am supposed to go to sleep when it gets dark out, right? That is how it goes in the summer when the last light hangs in the sky until after 9 p.m. I make use of every minute of light and often don’t arrive home until after 10. Now it is December. I yearn for those long hours of summer sunlight as I run with the dog in the dark, my headlight bobbing annoyingly on my forehead.
As I run along, I remember that the drastic change in the amount of daylight is only natural. And while the wild animals seem to adjust easily to the change, there is an aspect to this darkness that we can understand better than them. (Thank you, Copernicus.) According to the National Audubon Society Field Guide to the Rocky Mountain States (NASFGRMS), “Because the Rocky Mountain region (of the United States) is situated approximately halfway between the equator and the North Pole, this area is particularly sensitive to changing angles of sunlight striking the ground over the course of a year. As the earth moves around its orbit, its 23.5 degree tilt on its axis means that for half the year, the northern hemisphere is inclined towards the sun and the sun’s ray shine on it more directly; for half the year it is tilted away and the sun’s rays are more oblique. The sun reaches its lowest point over the northern hemisphere at the winter solstice,” (this year, on Dec. 22).
There is a fun website, http://aa.usno.navy.mil/data/docs/AltAz.php. that helps demonstrate just how low the angle of the sun is in winter compared to summer. In Durango, on June 22, 2011, the sun rose just before 5 am (standard time) in the northeast. At noon, the angle above the horizon was 76 degrees. This day saw over 15 hours of daylight! On Dec. 22, 2011, the sun rose around 7:30 am in the southeast and at noon the angle above the horizon was only 29.3 degrees. This low angle allowed for less than 9 hours of daylight.
What is a human to do with all this darkness? There are some outdoor activities that are only possible in the dark. Stargazing is one that everyone can enjoy. The constellation Orion is visible in the sky late at night in November all the way through to the early nights of April. According to the NASFGRMS segment on stars and deep-sky objects, “On winter evenings, we look outward though a spiral arm of our disk-shaped galaxy. Many hot, young blue and white stars along with some older, cooler yellow and reddish stars dominate the sky. New stars are being born in the Orion Nebula, a mixture of young stars, gases and dust visible to the naked eye or with binoculars as a fuzzy area on Orion’s sword, which hangs from his bright, three starred belt.”
Visit the SJMA bookstores to pick up a copy of The National Audubon Society Field Guide to the Rocky Mountain States. The book includes star charts as well as info about flora, fauna, geology and habitats. Visit the bookstore at www.sjma.org or at the any of the year-round locations.
Stars are easiest to see when there is no moonlight. Combine stargazing with a nighttime snowshoe walk and you can find fascinating new ways to not be afraid of the dark.
MK Thompson is the education assistant for the San Juan Mountains Association.