President Bernie Zelazny called the meeting to order at 7:30 PM in Room 309 Lawrence Hall on the Sul Ross Campus.  There were 17 people present.  Please note that we will resume meeting in our usual place in 204 ACR Building in August.

       Vice President John Bell gave a program on meteorites, asteroids, comets and Target Earth, asking whether humankind can survive the sort of impact that the dinosaurs didn't.  A videotape featured comet hunters Eugene and Carolyn Shoemaker and David Levy.  Gene Shoemaker was the geologist who showed conclusively that Meteor Crater in Arizona was the result of an impact, rather than volcanic activity as previously believed.  Meteor Crater is about 4,000 feet in diameter and 500 feet deep.  Such an impact in a populated area would of course be locally devastating.
       Several huge impact craters in excess of 100 miles in diameter have been found worldwide.  There is evidence that one such enormous crater, now buried on the Yucatan coast in Mexico, may be the location of the impact that killed off the dinosaurs about 65 million years ago.  A crater this size would require a meteorite or asteroid about 6 miles in diameter.  Such an impact would have darkened the sky worldwide for many months, grossly disrupting the food chain and leading to the demise of many animals.  Indeed, most of the species of animals then living died out soon after that impact.
       Working together, the Shoemakers and David Levy discovered Comet Shoemaker-Levy 9 in 1993.  The comet consisted of a train of about 20 fragments, some more than a mile in diameter.  These fragments were the remnants of a comet that was torn apart by tidal forces during a close approach to Jupiter.  It soon became apparent that SL-9 would impact on Jupiter, as it did in 1994.  The larger fragments raised fiery plumes that were seen by the Hubble Space Telescope and by some large earth-based scopes.  As the major impact areas moved into view around the edge of the planet, they were visible as dark spots  in modest amateur scopes.  Some of the impact areas were as large as the earth and remained visible for months in Jupiter's upper cloud layers.
       SL-9 shows us that the Age of Impacts is not over.  Each of the larger fragments struck with the explosive energy of all the nuclear arsenals on the earth.  One day, the earth will be threatened by such an impact.  With our growing space-faring skills, and with enough forewarning and luck, we may be able to divert such an object.  Cheers, everyone!
       John closed his presentation with a Comet Quiz.  Do you remember, for example, which comet was a big flop following a big media buildup?  Many thanks, John, for your latest effort.

       The business meeting took place after the above program.  Jim Walker moved the acceptance of the minutes for the June meeting as printed in the June Newsletter.  The minutes were so accepted.  There were was no treasurer's report because Treasurer Betty Grimm was out of town.

        With the ink barely dry on our lighting ordinance, the builder has just installed unacceptable wallpacks on the new post office.  These fixtures are 75% cutoff, which means 25% of their light goes upward.  They will also produce unnecessary glare for people on the ground, although I have not yet seen them turned on.  More than a year ago, postal officials promised that they would use only full cutoff lighting.  I have already begun taking steps to see that they do.

        June 22, 2000 - Images from a spacecraft orbiting Mars suggest that some craters may have recently been seeping water into the planet's surface and atmosphere.  If this is correct, it could prompt the National Aeronautics and Space Administration to pursue more intensive searches for life beneath the Martian surface.  A fresh look at pictures from the Mars Global Surveyor suggests that fan-shaped depressions near the rim of at least one Martian crater could be evidence for recent outflows of water.

If we have not yet received your dues, then please use the convenient envelope addressed to our treasurer that is included with this copy of your Newsletter.

Betty Lou Grimm, Treasurer
Big Bend Astronomical Society, Inc.
1001 N 2nd Street, Apt F-22
Alpine, TX 79830