Our Window on Nature

One of the Southwest’s most attractive plants, the Sacred Datura, is also one of its most deadly. Every now and then newspapers carry the grisly story of someone who, after experimenting with a species of Datura, wanders for days through desert delusions until brought down by the searing heat. While seeking heavenly visions, the user ignored the possibility that he might be creating his own physical hell. For along with the hallucinogens, this plant packs a payload capable of ending the search.

Otherwise known as thorn apple and Indian apple, the Sacred Datura is closely related to jimsonweed and is part of the nightshade clan, a worldwide plant family encompassing both reputable and notorious members. The most famous of these are tomatoes, eggplants, hot and sweet peppers, and potatoes. Of course, these plants were also considered poisonous in the past. Datura favors the less beloved branch of the nightshade family, the one implicated in murder, witchcraft, seductions, and orgies. (Read the rest …)

Next Tuesday morning (August 28^th) we’ll get to see the second total lunar eclipse of this year. Early in the morning the moon will begin its passage into the shadow of the earth.

Once a month (actually every 29 ½ days) the sun, earth, and moon line up to bathe our planet in the maximum amount of moonlight, allowing moon-watchers to view all the ridges and craters on the near side of the lunar surface. But it’s only several times a year when the alignment is correct for the moon to actually enter the shadow cast by our planet.

During partial eclipses it looks as though a bite has been taken out of the moon, and that’s the way it will start on Tuesday morning. However, since this will be a total eclipse, the entire moon will pass into the shadow region, and for an hour and thirty-one minutes the sun’s light will be blocked by the earth. But the moon doesn’t actually disappear.

Even without direct light the moon will still be visible. As the sun’s rays pass through the earth’s atmosphere, they are slightly refracted (bent), and depending upon the amount of cloud cover and dust in the air, these curving rays will tint the moon in some shade of copper or red. The color is caused by the same phenomenon that gives us beautiful sunrises and sunsets. But this time the color is picked up overhead by the darkened moon.

An eclipse is one of the best times to study the moon. As the shadow of the earth rushes over the lunar surface, it will help highlight the various moon features. A pair of binoculars will make your view even better, and if you do a bit of preparation you’ll know where to look and what to expect.

You can print out a moon map from Space.com. Just point your computer to http://www.space.com/images/skywatchers_moon_map.gif and send the image to your printer. There is also a beautiful detailed topographic map of the moon, showing the seas, craters, and mountains at http://cseligman.com/text/moons/moonnear.htm.

The best show will be on the west coast, starting at 1:51 a.m. Pacific Daylight Time, with the total eclipse starting about an hour later. Add an hour for each time zone as you move east. Unfortunately on the east coast the sun will rise about half-way through the performance. The entire display will last a little over three and a half hours.

The moon image (with added labels) was taken from the Distant Suns computer program. Distant Suns has both a free and a commercial software program that will display the night sky right on your computer. It’s what I use to help me explore the heavens. Check out their website at http://www.distantsuns.com/.

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/.

Just about everybody likes to eat insects - mammals, birds, amphibians, reptiles, spiders, other insects, and even some humans. Over in Great Britain, a scientist with time on his hands calculated that the country’s spiders consume enough insects each year to total the combined weight of the entire human population. And that’s just the spiders. Why, then, are there so many insects left over?

“Bug-ologists” point to several reasons why insects are nature’s most successful creatures. For one thing, insects breed in astronomical numbers. They can afford to lose a high percentage of their population to predation. And for another, insects have highly sophisticated strategies for self-defense. It’s these defense strategies that we’ll be investigating here - house building, chemical warfare, warning coloration, mimicry, and camouflage - because they are strategies that you’ll be able to view first-hand as you travel. First the architects. (Read the rest …)

When we think of palm trees, we imagine tropical beaches and pineapples, and dancing girls shaking their hips to the rhythm of drums. Palms belong in Hawaii or Bali, or at least in the Florida Keys.

In California, however, native fan palms are surrounded by desert. Sound like a contradiction in terms? These California fan palm oases aren’t widespread, but rather are tiny pockets of vegetation, a carryover from a time when the entire area was blessed with a tropical climate.

Isolated though they are, you can still visit some of these palm oases on your next trip to the Southwest.

During the Miocene and Pliocene epochs, southern California, northern Baja, and western Arizona enjoyed warm and wet weather. Sunny skies still dominate those regions, but now water is limited to trickles and ponds. Beyond reach of the moisture, desert extends toward the horizon, giving life to a few mesquite trees, and patches of creosote bushes and bur sage. (Read the rest …)