Tuesday, November 24, 2009
The morning of June 3, 2009 brought overcast skies and drizzle to Colorado Springs, CO - dampening my hopes of a clear day on a field trip to nearby Pikes Peak (at 14,110 ft, Pikes Peak is one of Colorado's 54 "14ers"). Assured by the folks who run the Pikes Peak Cog Railroad that the summit was clear, we boarded the train for the ride to the top.
It wasn't long before we broke free of the clouds, and soon were way above treeline in a few inches of new snow! From the summit we were able to look back down toward the cloud covered Colorado Springs and the plains to the east, where it remained cloudy and wet for the rest of the day.
Tuesday, November 17, 2009
We've all seen them...my friend Donald calls them "God Lights". The the rays of sunlight that seem to radiate out from the sun through breaks in the clouds are more properly known as "crepuscular rays". We see them because sunlight is scattered by dust and other particles in the atmosphere making the air lit by the sun appear brighter than the air that is in the shadow of the clouds. Though the rays are virtually parallel to each other, perspective causes an apparent convergence toward the Sun in the same way parallel railroad tracks seem to converge in the distance.
This image of some bright crepusculars was made late one afternoon in Bedford, NY. Note the particularly dark shadow on the right side of the photo, also parallel to the light rays, cast by the clouds there.
Tuesday, November 10, 2009
(image courtesy of http://leonid.arc.nasa.gov/HDTV_LEO50mm-1.jpg)This year's Leonids should put on a good show, as the New Moon will not be in the nighttime sky. Peak viewing will be in the wee hours of the night of November 17-18. Here's some good information on how to view meteor showers, and information on all the periodic meteor showers we experience throughout the year.
See the Westchester Astronomers November newsletter for more upcoming sky related events.
Thursday, November 5, 2009
While attending the Earth Science Information Partners conference at UC Santa Barbara last summer, I enjoyed a nice walk along the beach from the dorms to the conference center each morning. I was struck particularly by the vast number of holes apparently drilled into the rocks along the shore, many of them containing clam shells that just fit into the holes. A closer look at those shells reveals that it's the clams themselves that make those holes!
Examination of the clam shells reveals the sharp ridges visible in the close-up picture on the right. By persistent grinding and rotation of the cutting edges of their shells against the rock, these "rock boring clams" create safe homes for themselves in solid rock, and in doing so accomplish significant weathering of the shoreline rocks, and contribute significant sand to the beach. You can read more about boring clams here: