Image Source: Melissa Farlow, National Geographic
Well, okay, Groundhog Day is tomorrow. But, as I won't be blogging tomorrow, I wanted to get a word in edgewise on this most noblest of astronomical holidays.
For those of you who may live in a country not blessed with such a glorious holiday, let me explain the day. On February 2, the legendary groundhog, a furry woodland animal that looks exceptionally cute but is not always the most friendly of the beasts, awakens from its winter hibernation and sticks its head out of the ground. If the groundhog sees its shadow, it is spooked (not being among the most clever creatures) and runs back in its hole to sleep for another six weeks. If it doesn't see its shadow, it happily scampers about, and we get an early spring.
Of course, this legend has little to do with reality. The fact is that, whether or not the groundhog sees its shadow, there are another six weeks of winter. Look at your calendar, count 6 1/2 weeks into the future, and you'll see the first day of spring. Now count backward 6 1/2 weeks, and you'll see the first day of winter. Groundhog Day is halfway between the winter solstice and the spring equinox. And that is not coincidence!
These days halfway between an equinox and a solstice are called the cross-quarter days. They used to play a large role in pagan cultures (and still do among neo-pagan religions). We even have "holidays" on or near three of the four cross-quarter days: Groundhog Day, May Day, and Halloween.
What does a cross-quarter day mean for us? Not too much -- most of the northern hemisphere is in the middle of a cold winter, hoping that spring will come soon, and the southern hemisphere is enjoying summer vacation, and hoping that summer lasts a little longer. Around now you will probably start to notice the days getting noticeably longer pretty quickly. Around the winter solstice, the length of the day stays pretty constant for a while, but as the Earth continues to speed around our sun, the sun will appear to rise higher in the sky (for those of us living in the north), the days will get longer, and, eventually, the temperatures will get a bit warmer.
I make a big deal out of days like this, I realize. It's because the seasons are one of the most obvious links we have to the larger Universe around us, and one that most Americans don't understand. And it's a hard picture to grasp -- we are on a tiny ball of a planet that spins once a day and goes in circles around our parent sun once a year, which itself is orbiting the Milky Way galaxy every 250 million years, and our galaxy which is moving around our neighbor galaxies and slowly falling toward a cluster of galaxies 60 million light-years away. We're in constant motion, most of it extraordinarily slow by galactic standards. But we can sense some of it -- our planet's spinning, and its motion around the sun -- and these motions intimately affect our lives. Once we can grasp that, we've started to open our minds to a much larger universe around us.