Vice President Bernie Zelazny opened the meeting at 7:30 PM, pending the arrival of President John Bell expected later.  There were 15 people present, including 2 visitors.

       John Bell presented a video on the history of our solar system, produced by The Learning Channel.  The video began by asking, What will be the fate of the sun?  To arrive at possible answers to this question, we must observe the sun over time.  The estimated lifetime of the sun is 10 billion years, so we have observed the sun for only a tiny fraction of its expected life.
       By observing other stars, the Hubble Space Telescope has provided insights into the likely history of the sun.  Because the HST is well outside the earth’s turbulent atmosphere, it provides a view 10 times clearer than any telescope on the earth.  Furthermore, the HST can see objects at a distance of 10 billion light years.
       We have learned that Eta Carinae is a star on the verge of becoming a supernova, so we will continue monitoring its activity.  The famous Crab Nebula is the expanding remnant of a supernova explosion, as are the Veil Nebula and the Pillars of Creation.
       About 6 billion years ago, a shock wave is thought to have swept through our galaxy, possibly compressing the gas and dust in our galactic disk into the planets of our solar system and other regions of the galaxy.  Metals tended to remain near the center of our solar nebula, while gases were driven off to the outer regions.  Today, the inner planets, Mercury, Venus, Earth, Mars, and the Asteroids, are rich in metals.  Mercury, the innermost planet, may be rich in gold and platinum.  The outer planets, Jupiter, Saturn, Uranus, and Neptune are made largely of gas, and are often called the gas giants.  Pluto, although the outermost planet, is somewhat unexpectedly a solid, rocky object.
       With the aid of the HST, we can see the probable formation of solar systems in other regions of our galaxy.  For example, the Orion Nebula has disks of gas and dust the size of our own solar system.  The star Beta Pictoris has a flattened disk of dust that may be giving rise to planets. 
       Geoff Marcy and Paul Butler, San Diego State University astronomers, showed some of their early lightcurve data showing evidence of an extra-solar planet orbiting a distant star.  The light from such a star is shifted in wavelength as an orbiting planet tugs the star in different directions.  [Marcy and Butler have become the premier extra-solar planet searchers, having found about 50 such planets.]
       Mariner 10, one of our space probes, has returned extensive information on the planets.  Mercury keeps the same side toward the sun, which is heated to about 800 deg Fahrenheit, while the dark side stays at minus 300 F.  Venus and Earth were originally similar, but became very different long ago.  Much of the carbon dioxide in Earth’s atmosphere was collected in sedimentary carbonate rocks, but Venus lacked sufficient water for such a process.  The large amount of carbon dioxide remaining in the atmosphere of Venus resulted in a runaway greenhouse effect that heated the planet beyond any presumed ability to support life.  On Earth, the temperature became just right for the development of life.
       Mars is now similar to the Earth about 4 billion years ago.  Having lost most of its atmosphere, Mars now seems inhospitable to life.  The Asteroids, mostly small rocky bodies, are even less hospitable.
       Jupiter is the first of the gas giants as we move outward in the solar system.  The Great Red Spot is a rotating storm system about 15,000 miles in diameter visible in Jupiter’s upper atmosphere.  [The Great Red Spot has been observed continuously for about 350 years.]  The four largest moons, Io, Europa, Callisto, and Ganymede, are readily visible in small telescopes, and were in fact observed by Galileo in 1610.  Numerous smaller satellites have been discovered since.
       Saturn, known for its famous rings, is a favorite object in modest telescopes.  The rings are very thin, consisting of widely separated ice bodies up to about 30 feet in diameter.
       Uranus was discovered by the British astronomer William Herschel.  Unlike the other planets, Uranus’s axis of rotation is nearly parallel to the plane of the solar system.  The several moons of Uranus, like other moons, orbit the planet in its equatorial plane.  Thus, the system of Uranus and its moons is tilted about 90 deg away from the usual orientation of a planet and its moons.  It appears that Uranus may have been struck by a very large object that greatly changed the orientation of its axis.
       Perturbations in the orbit of Neptune led to the idea that there might be an unknown Planet X orbiting beyond Neptune.  Clyde Tombaugh, a largely self-educated Kansas farm boy working at Lowell Observatory, discovered Planet X in 1930.  The new planet was soon named Pluto. 
       In his search, Tombaugh took hundreds of pairs of photographic plates.  The plates within each pair were taken at different times.  Using a blink comparator, when the two plates of a pair were shown rapidly one after the other, the fixed stars appeared stationary but the image of Pluto clearly moved through the field of stars.  The video showed this movement very nicely.  The appearance of prominent astronomers Heidi Hamel, Carl Sagan, and David Levy added greatly to the video.
       Unlike the other outer planets, which are gas giants, Pluto and its moon Charon are small, solid, and rocky.  It may be that Pluto is a member of the Oort Cloud, a region of solid objects extending about 1/3 of the distance to the nearest stars.  Comets are thought to originate in the Oort Cloud.
       As impressive as they are, the planets and asteroids comprise only about 1% of the mass of the solar system, the sun accounting for most of the rest.  Earlier astronomers thought the sun was a mass of burning coal.  We now know that the sun is powered by nuclear processes that heat the core to a temperature of 20 million deg F.  Solar prominences rising from the surface of the sun can extend hundreds of thousands of miles, sometimes interfering with electrical power transmissions and communications.
       The death of the sun is written in the stars.  Planetary nebulae, such as the Cat’s Eye and the Ring, are glowing shells of gas and dust blown off by their central stars in their death throes.  Like many other stars, our sun will become a white dwarf in about 5 billion years. . .  Watch for developments!

       (Edited from NASA.)  The Sun now appears a little bigger than usual.  That's because Earth reached perihelion on January 3, our annual closest approach to the Sun.
       Because of Earth's slightly elliptical orbit, we are about 3 million miles closer to the Sun in January than we are in July.  Then why is it so cold outside, in the northern hemisphere?  Follow the links at http://www.spaceweather.com for the answer.

       (Edited from the BBC, January 8, 2003.)  Is the effect of gravity instantaneous, or does it take time to travel from one object to another?  Newton thought the effect was instantaneous, but Einstein believed that gravity traveled with the speed of light.  Recent observations support Einstein’s view.
       Two American astronomers, Ed Fomalont of the National Radio Astronomy Observatory and Sergei Kopeikin of the University of Missouri, measured the bending of radio waves from a distant quasar as Jupiter moved in front of the quasar.  Jupiter’s gravity caused a change in the apparent position of the quasar, allowing the speed of gravity to be found.  These observations were presented at a recent meeting of the American Astronomical Society and published in the New Scientist.  (Thanks to Bernie Zelazny for calling our attention to this item.)