Christmas day to bring a partial solar eclipse

Winter solstice also among

December's astronomical events.

See ECLIPSE, page 5

Eclipse

By MIKE FORD

Special to The Capital-Journal

This month brings many celestial activities to see, including a partial solar eclipse on Christmas Day.

As December opens, the sky is full of planets to observe. In the southwest, the planet Venus is the bright beacon that outshines all the stars in the sky. Venus appears bright because the sun reflects off of the clouds of sulphuric acid in the upper atmosphere. This "twin sister" of Earth is also the hottest planet in our solar system. Even though Venus is farther than Mercury from the Sun, heat gets trapped under the clouds in a runaway greenhouse effect. The average temperature exceeds 800 degrees Farenheit, hot enough to melt lead. As the month goes on, the angle between Venus and the Sun increases, meaning it sets later in the evening. On Dec. 29, one hour after sunset, Venus has a close grouping with the crescent moon. This is called a conjunction, which occurs several times throughout the year.

Looking to the east, the two largest planets, both gas giants, in our solar system are easily visible. The brightest one is Jupiter. This large ball of hydrogen and helium is approximately 88,000 miles in diameter and is egg-shaped because of its rapid rotation. Each jovian day on Jupiter is approximately ten hours. Because of this rapid rotation, centripetal force pushes it down at the poles and makes it bulge at the equator. A small telescope will reveal this unusual shape along with the four bright Galilean satellites .

To the upper right of Jupiter is Saturn, the ringed planet. Saturn has the same make-up as Jupiter, but is a little smaller with a diameter of approximately 75,000 miles. Looking at this planet easily will reveal the rings and, if the sky is clear, some of the satellites. Near the rings is the satellite Titan. Titan is the only satellite with a thick atmosphere. In 2004, the spaceprobe Cassini will arrive at Saturn and send a probe to explore the satellite. As the probe descends into the atmosphere, high intensity lights will illuminate the landing area. When the probe gets close to the surface, scientists hope to get a good view of the surface of Titan. They believe it could have large oceans of methane and snow consisting of frozen ammonia. Between Jupiter and Saturn is a small dipper-shaped group of stars. These are the Pleiades, a large cluster of young, blue, hot stars. They are just beginning their life cycle and will burn for several million years. Even though you might see six or seven in this cluster with the naked eye, there are approximately 250 stars in this cluster. They are a part of the larger constellation of Taurus, the bull. Below the Pleiades is a V- shaped group of stars; the Hyades. They are old orange and red stars that are moving through space at about 50 miles per second. But, because they are so far away, movement can't be detected.

While the sky is full of interesting objects to see, there are a couple of events that are worth mentioning. On Dec. 21, the sun will reach its farthest point to the south. At 7:37 a.m. CST, the sun will rise directly in the southeast and later will set directly in the southwest, marking our longest night and shortest day. This is called the winter solstice. Right after the winter solstice occurs, the sun slowly will begin to move northward, making the days longer and the nights shorter. However, don't look for an immediate change. The difference in sunset and sunrise is only two minutes per day.

The next interesting sky show is on Christmas morning, when people in most parts of the United States will see a partial solar eclipse. From Kansas, the sun will be covered about half by the moon. The eclipse will begin about 9:45 a.m. and will be done by 11:30 a.m. But be warned! Don't look at the sun without eye protection! A short glance at the sun will cause permanent blindness. On March 7, 1970, several hundred people went blind when a total solar eclipse headed up the eastern seaboard in the United States. Because your corneas are like little magnifying glasses, they focus the light on the back of your eyes and burn out the rods and cones. You can either project the image of the sun or view it directly using a solar filter.

If you would be interested in solar views, please e-mail mford@holtonks.net. Filters are $1 each, which includes postage. This is a fun event to view, especially on Christmas Day. But, do it safely. If you have a small telescope, the best way to view it is by projecting the sun on white cardboard. Solar filters are to be used mounted on the front of the telescope only. Don't use filters that screw into the base of the eyepiece. People have gone blind using these filters. Elk Creek Observatory in Holton will be open for viewing the eclipse beginning at 9:30 a.m.

If you are interested in astronomy and would like to join a group of amateurs, consider the Northeast Kansas Amateur Astronomers League in Topeka. The organization meets at 7:30 p.m. on the fourth Thursday of each month at Stouffer Science Hall on the Washburn University campus. Moon phases this month: first quarter --- Dec. 3; full moon - -- Dec. 11; last quarter --- Dec. 17; new moon --- Dec. 25.

Mike Ford is an astronomy and science teacher at Holton High School.

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