Our Window on Nature

What more could you ask? Warm summer weather — a new moon (the darkest night) — and one of the most consistent meteor showers of the year. If you’re willing to give up a little sleep, this weekend should be a wonderful show.

On the night of August 12th and the morning of August 13th the Perseid meteor shower should reach its maximum, with the potential of over a meteor a minute. The display occurs as the earth passes through the debris trail left by the Swift-Tuttle comet.

Small meteors enter the earth’s atmosphere every day, but only during a meteor shower do enough appear that you can be sure of seeing them. We actually entered the edge of the Swift-Tuttle trail back in mid-July, so the number of shooting stars has been increasing nightly. If you can’t catch the featured event on Sunday night and/or Monday morning, there are still more meteors than usual just before and after that date.

On August 12th (Sunday) the show gets a slow start around 9:00 pm with what are called Earthgrazers. According to Bill Cooke of NASA’s Meteoroid Environment Office these are “long, slow and colorful; they are among the most beautiful of meteors,” but you will probably only see several of them per hour.

The frequency of meteors keeps improving throughout the night, with the most concentrated portion of the shower occurring before dawn on Monday morning. Although some of the brightest meteors will be visible from urban locations, try to get away from city lights. Give your eyes about 20 minutes to adjust to the darkness, and then watch the darkest portion of the sky.

The photograph of the Perseid Meteor Fireball shown above was taken at Joshua Tree National Park by Wally Pacholka in 1999. Winner of both a Time Magazine and a Life Magazine “Picture of the Year” award, Wally has a spectacular web site featuring comet and meteor photography. Check it out at http://www.AstroPics.com/.

The Winter Solstice is almost upon us (at least in the Northern Hemisphere), and according to many that brings on the first day of Winter. I wonder if we should tell that to all those digging out from this year’s early snowstorms. But December 22nd does, at least, have the longest night and the shortest day.

Because the axis of the earth is tilted, as we make our yearly journey around the sun different parts of the earth receive increasing or decreasing amounts of sunlight. And the amount of sunlight, of course, affects the temperature. But as with most things in nature, it’s not quite as simple as it sounds.

If you heat a pot of water on a stove, turning off the burner doesn’t immediately bring the liquid back to room temperature. In the same manner, after the oceans and landmasses have been heated during the summer, the warming effects don’t disappear as soon as the days start becoming shorter.

Of course the same is true in reverse, and it will be a while before we see the first signs of a new season. But the solstice is the turning point, both in the gradual change in the angle of the sun’s rays, and in the number of hours we can spend outdoors watching things like the changing seasons.

NASA released several photos today showing the possibility of water on Mars. They didn’t actually find the water, but by comparing photographs taken in August 1999 with the same location in September 2005, there is exciting news. The new picture shows a major change that occurred some time in the last five to seven years. According to the NASA website

The atmosphere on Mars is so thin that liquid water cannot persist at the surface. However, researchers propose that water could remain liquid long enough, after breaking out from an underground source, to carry debris before totally evaporating and freezing.

The photo at the left shows the before and after pictures, and scientists believe the several hundred foot long white streak was caused by flowing water. If this is the case, it increases the possibility of finding microbial life on Mars.