Each day, we also are getting closer to Our Sun. Yes. You read that correctly. Perhaps you remember from your grade school science classes that the Earth’s orbit around the Sun is not a perfect circle, and though it may be hard to believe, during our current orbit, the Earth will be closest to the Sun on January 2, 2o13.
Clearly, distance between the Sun and the Earth does not cause the seasons. So what does? Well as my students…..”learners of all ages” from pre-schoolers to participants in Learning in Retirement know, I answer almost any question about astronomy with: “there probably was a collision.” Indeed, though astronomers don’t know for sure, the current thinking in the scientific community is that the impact that created our Moon sort of knocked the Earth off kilter so that it is tilted in relation to the Sun.
This 23.4 degree tilt makes all the difference in the world. Or I should say, all the difference for the world, because axial tilt gives us our seasons. In summer, the Northern Hemisphere is tilted toward the Sun. But in winter, when our hemisphere is tilting away from the Sun, our days are shorter, the Sun appears to be lower in the sky, and it also seems to rise and set in different places. In winter, we receive less solar energy than we did in summer. Here at Crossroads, our solar collectors produce less electricity. And our shadows are longer.
This means that a garden variety sundial is almost always wrong. The shadow cast by the gnomen (the sticky-up part, pronounced No-Men) changes from day to day, certainly from month to month. And that is why the Door Peninsula Astronomical Society and Crossroads had dreamed of installing an analemmatic sundial, which means the gnomen is placed at a different location during different parts of the year. And we wanted a sundial on which a human acts as the gnomen.
Saturday, at 1:00 in the Astronomy Campus of Crossroads (located off the Utah Street/Cove Road intersection on the recently named StarGazer Drive,) DPAS will dedicate the Sundial, which was the project of the Leadership Door County Class of 2012. The artistic installation was designed by Jim Dufrane with mathematical assistance from Ray Stonecipher. Dufrane created the tiles which were installed by members of Leadership DC and DPAS. The project was made possible with a grant from the Raibrook Foundation.
Following the dedication and demonstration of this artistic installation, members of the Door Peninsula Astronomical Society, Friends of Crossroads and area teachers will offer activities which celebrate the sun. Weather permitting, they will offer safe solar viewing. But sunny or not, Observatory tours, demonstrations about the sun, video programs on the 3-D Sun, exhibits featuring The Sun in fine art and other hands-on activities will be offered in the Stonecipher Astronomy Center and the Colling Learning Center.
Thanks to a grant from the Door County Milk Marketing Board, participants will enjoy Ice Cream SUNdaes and kids will be able to win educational prizes.
Astronomy Day 2012 will be topped off with an evening of NightSky Viewing (clear sky only) at in the StarGarden beginning at 7:00.
Crossroads at Big Creek is a preserve welcoming learner of all ages to programs in science, history and the environment. The Collins Learning Center, located at 2041 Michigan, is open 2:00-4:30 daily and during scheduled activities.