Astronomy News from Lynchburg College

Moon Halos

Can you see a rainbow at night? If you were out last night in Lynchburg, you most certainly could and probably did. The full moon was at the center of a rainbow-colored ring of light-a halo-with a radius of 22 degrees, red on the inside of the ring and blue on the outside.

Two things are required for this phenomenon-a bright light source, and high cirrus clouds containing ice crystals between you and the source. Light is refracted (or bent) as it passes through these hexagonal ice crystals; the most likely angle of refraction is 22°. White light is made up of light of different wavelengths, and each of these is bent at a slightly different angle. This results in red light (longer wavelength, bent less) appearing on the inside of the ring of light.

You see these 22° halos around the sun when the necessary cirrus clouds are present. It rarer to see them around the moon, because the moon is much less bright, especially when it is not in its fully illuminated phase. When the moon is less than full, you may see a ghostly ring around it, but it will probably not be bright enough to trigger your eye's color sensors and will therefore just look white. A full moon is usually required to bring out the rainbow effect.

What you are seeing is reflected sunlight, after all. The full moon looks very bright against a dark sky, but you can safely look directly at it. It is a very poor mirror, reflecting only about 12% of the sunlight that falls on it. Even that low percentage is enough to let you read a newspaper by the light of the full moon!

Water on the Moon!

Who would have thought it? One of the distinguishing characteristics of the lunar samples brought home by the Apollo astronauts was their complete lack of any trace of water. There was no water trapped in the crystal structure of the rocks, and no evidence that the rocks had been formed in the presence of water. The surface of the moon is baked at up to 240°F at lunar noon, and there is absolutely no atmosphere that might hold traces of water vapor.

But...there are deep craters at the moon's south pole that never see any sunlight. Just as at the Earth's polar regions, the sun never rises high above horizon here, and the temperature is as cold as any place in our solar system. 33 Kelvin degrees above absolute zero is cold enough to prevent any ice from turning into vapor and escaping to space. Where did the water come from? Comets impacting the moon throughout its history could bring sufficient water to account for what we have so far detected. More details here.

What does this mean for the prospects of humans establishing a presence on the moon? Water is useful for more than just drinking. Its hydrogen and oxygen could be used for rocket fuel (the huge orange external tank of the space shuttle holds these substances in liquid form), and the oxygen could provide breathing air. The future of the human spaceflight program in this country is uncertain. Even after a spectacular test launch a few weeks ago of a proposed new rocket for human flight, a commission appointed by President Obama has stated that NASA needs about $3 billion more annually to carry out the missions proposed during the previous administration. Should we go back to the moon, 40 years later, so we can beat the Chinese to it? Is there a compelling reason to do so, or should we aim elsewhere? Perhaps a rendezvous with a near-Earth asteroid, with a view toward learning how to mitigate the collision danger they pose to our planet? Why not to Mars? (The argument for that can be found here.) Stay tuned!

Leonid Meteor Shower

This often has the potential to produce a spectacular meteor shower, if not an actual meteor storm. In 1999, 2001, and 2002, there were spectacular showers, with a meteor every few seconds. The Leonids are responsible for one of the most spectacular meteor storms in history, that of 1833. Observers in North America reported up to 200,000 meteors per hour, a rate that would mean more than 50 meteors per second. Many were convinced that Judgment Day had arrived!

Predictions are for a rate of up to 500 per hour in 2009, peaking around 4:43 p.m. EST on November 17th. The moon will be out of the sky, so we can only hope the clouds cooperate and that there are a few meteors left for us to see a few hours later when it is dark in Virginia!

The Moon on YouTube

The Japanese Kaguya spacecraft orbited the moon for almost two years before it was deliberately crashed into the surface last June. On board were two high-definition video cameras, with no particular scientific purpose-mainly for public relations. I'd say they fulfilled their purpose. The Japanese space agency has a YouTube channel of some of their most spectacular images. I can't read Japanese, but the images are impressive in any language.

2012--Movies and Real Life

For several years now, I have been getting questions about the imminent end of the world. No, I'm not talking about final exams, but about the end of the Mayan calendar, the crossing of the galactic plane, the return of a rogue planet, Sarah Palin's new book-anything will do when we are talking about the end of civilization that supposedly awaits us. Repeat after me-it is only a movie. It is fantasy. It is meant to entertain you, not to inform you. I may even go see it myself, especially after reading this hilarious review from Roger Ebert. But I won't lose any sleep over what might be coming in December 2012.You may or may not find a NASA scientist's statements to be reassuring (aren't these the guys that perpetrated the moon hoax?), but this is more authoritative than all the...stuff...that pops up when you search on 2012. Rest easy.

Describing the Indescribable

How can you describe the indescribable? Regardless, I'm going to try.

We missed first contact (when the moon first begins to block out a portion of the sun's disk) because the sun was hidden by clouds at the exact moment. It would come out long enough for us to see it, then disappear behind another cloud, but we could definitely see the progress of the moon's shadow, starting at about the 4:00 o'clock position and moving across the face of the sun. I had my "eclipse glasses" that let me safely look directly at the sun, and Jane was using those and taking pictures through our camera with a sheet of aluminized Mylar held to the lens with a couple of rubber bands.

The captain and the consulting astronomers maneuvered the ship beautifully to put us in a "hole" that was relatively free of clouds. He even had the engineer fire up some idle engines to put on a burst of speed and get us to the hole. It meant that the planned orientation of the ship, with the sun off the starboard side, shifted to put it just off the port bow. Our position on the top deck at the bow of the ship worked out perfectly. There were some folks who had staked out positions at the side of the ship who had to move or miss it.

A few minutes before totality, the temperature and the light level had both dropped noticeably, and the sun was in the clear. Owen Gingerich called out from the bridge that we were two minutes from totality, and I think that's when the enormity of this really hit me. I have seen partial eclipses before, and while they are undeniably cool, I knew a total eclipse would be an entirely different experience. I took off my eclipse glasses and looked in the general direction of the sun without looking directly at it. The light level continued to drop. I looked at the horizon directly beneath it, looking for the shadow of the moon as it approached. I could see (faintly, not that obvious) a column of darkness getting wider as it moved toward us. The shadow of the moon was coming toward us at more than 1000 miles an hour.

Just before totality, as the last sliver of the sun's bright photosphere disappears, there is the "diamond ring" effect-one bright spot (the diamond) flaring out at the 10:00 o'clock position, then disappearing. The sun disappears behind-there is no better way to put it-a black hole in the sky. Surrounding it was the sun's corona, a white, ghostly outer atmosphere. All around the horizon that we could see (about 270 degrees), it was twilight. It was brighter than I expected, seeming brighter to me than the full moon. Mercury was easily visible above and slightly to the right of the sun, and Saturn (less bright) above that.

I just stared at this incredible sight. There is no way to convey the sights (and sounds, when there are hundreds of people surrounding you) in any sort of image or video. Euphoria, awe, wonder-it's even better than I had imagined. It isn't like night time-it isn't simply the absence of the sun. It is a presence-a presence of an absolutely black disk in the sky, surrounded by a white fringe.

Totality for us was 3 ½ minutes. Toward the end, I could see the corona brightening near the point where the sun would emerge from behind the shadow. Suddenly there was a bright pink rim at that point, and even before someone shouted out "Chromosphere!" I knew what I was seeing. Just above the bright "surface" of the sun is a layer whose light is dominated by emission lines from hydrogen. The moon had moved just enough to expose that for a few seconds. Immediately after was the second diamond ring as totality ended. Shouts, whoops, clapping, emotional outpouring, champagne toasts, congratulations to the captain, because no more than two minutes after totality, the sun pretty much disappeared behind a cloud.

Jane was diligently taking pictures, for which I am grateful, because they can convey at least a little of what we saw. But there is no camera equal to the human mind. This is a memory I will carry with me for as long as I live.

Total Solar Eclipse in July

Most people have never in their lives seen a total solar eclipse. While solar eclipses are not exceedingly rare-there is one roughly every year or so-the phenomenon of totality, with the bright surface of the sun completely occluded by the moon, is one that is limited to only a small part of the Earth's surface. You really do have to be in the right place at the right time.

Why is this? Total lunar eclipses are generally visible over entire hemispheres. The last total lunar eclipse in February 2008 was visible from anywhere in South America, anywhere in North America except the west coast, from western Europe and Africa, and even from Greenland! And lunar eclipses are relatively lengthy as well, the February eclipse having a 50-minute period of totality. A total solar eclipse that lasts as long as 5 minutes, on the other hand, is considered quite a long one.

First of all, you'll have to picture the relative positions of the sun, the Earth, and the moon during both lunar and solar eclipses. I'm going to try to help out this process with pictures, because I know if this is new to you, it's hard to get those pictures into your head without some assistance. And I'm going to move from the simplest basics of eclipses to more complex features, so jump in wherever you feel comfortable starting.

Sun, Earth, and moon: Eclipses take place when sunlight is prevented from falling on either the Earth or the moon by the other body. Total lunar eclipses take place when the Earth blocks sunlight that would otherwise fall on the moon; total solar eclipses take place when the moon blocks sunlight that would otherwise fall on the Earth.

(Click for the full-sized image)

Lunar versus solar: The earth is a lot bigger than the moon, with an 8000-mile diameter compared to the moon's 2000 miles. That makes the Earth's shadow much bigger as well. At the Earth-moon distance, the Earth's shadow is more than big enough to completely cover the moon. This makes lunar eclipses longer since it takes the moon some time to traverse the Earth's shadow, and it means that if you are anywhere on the side of the Earth facing the moon while it does so, you will see the eclipse. The moon's shadow, however, is just barely long enough to reach the Earth's surface. At any given instant, only a small spot on the Earth is completely blocked from sunlight. Viewed another way, the moon's apparent size is essentially the same as that of the sun. (The moon is both 400 times smaller and 400 times closer than the sun; an interesting coincidence.) As the moon travels across the face of the sun, it only blocks it for a few minutes at most.

Partial versus total: The sun is an extended object as opposed to a point source like a star. Stars are so far away that even though they are large objects, they only appear as points of light to us. When the moon moves in front of a star, there is no such thing as a "partial" occultation: one instant you see the star, and the next instant you don't. (And yes, you purists, I know there are complications like diffraction and the not-completely-smooth edge of the moon, but hush up for now.) But the sun can be partially eclipsed, with only part of its bright surface being obscured by the moon. Many of you probably have seen a partial solar eclipse at some point.

Why not every month? When the moon is new, the side facing the Earth is in darkness; it is the side facing away from us that is being illuminated by the sun. So why isn't there a total solar eclipse every time there is a new moon? It is because the moon's orbit around the Earth is not in the same plane as the Earth's orbit around the sun. If that failed to register with you, take a look at the diagram below (click for the full-sized version):

The blue plane is created by the path of the Earth around the sun: the Earth and the sun are always "lined up" with each other in this plane. The brown plane is created by the path of the moon around the Earth: the two of them are always "lined up" in this plane. Here's the key point: all three of these, the sun, the Earth and the moon are "lined up" only where these two planes intersect each other. This is along the "line of nodes" indicated in the diagram. The diagram below now should make more sense to you:

Why not always the same length? The last total solar eclipse was in August of last year, and at its point of maximum eclipse duration, totality was 2 minutes and 27 seconds long. This July's eclipse will have a maximum duration of 6 minutes and 39 seconds. Why the difference? It is because the moon's path around the Earth is not exactly circular, but is one that brings it sometimes closer to and sometimes farther away from the Earth. When an eclipse takes place with the moon at its closest point to the Earth, the moon's apparent size is corresponding larger, and the moon covers the sun completely for a longer period. When the moon is farther away, its apparent size drops along with the duration of totality. When the moon is at its most distant, it is too small to completely cover the sun's disk. The moon will be centered on the sun, but there will be a "ring of fire" around the edge of the dark moon. This annular eclipse (the Latin word for ring is annulus) is illustrated below:

What's so special about the July 2009 eclipse? Its duration for one thing. At 6 minutes and 39 seconds, it is close to the maximum duration possible (7 minutes and 31 seconds). Its location for another. Beginning in India, its path will carry it across central China and smack dab over Shanghai, making this possibly the most widely viewed total solar eclipse in human history. The path continues out into the Pacific south of Japan and ends just north of the Cook Islands. For eclipse chasers, totality at sea is a bonus. A ship offers easy mobility to avoid clouds and the sea gives a perfectly flat horizon to see as much of the sky as possible. And no, you won't be able to see it from Lynchburg; it will be taking place in the middle of the night here. Wrong side of the Earth!

Where is a good source of information about past and future eclipses? The NASA eclipse page is unsurpassed, I think. Here is the general page from which you can go to learn more about specific eclipses: http://eclipse.gsfc.nasa.gov/eclipse.html

What's this Saros 136 thing? Wasn't that the name of Spock's father? Actually, that was Sarek, Vulcan ambassador to the Federation. (Sorry-had to get my geek on.) A saros is an eclipse cycle of 18 years, 11 days and 8 hours, during which period of time the sun, Earth and moon return to roughly the same relative geometry and a nearly identical eclipse occurs. Because of that 8 hours, the second eclipse will occur 120° west of the first, since the Earth has rotated an extra ⅓ of a day past its original position. Interestingly, the ancient Babylonians knew of this cycle 3000 years ago, and could use it to predict future eclipses.

I caught that fudging! "Roughly" and "nearly"-what's up with that? Well, there is one more geometric complication to throw at you. You know that line of nodes we talked about earlier? It doesn't stay in the same place relative to the Earth and the sun; rather, it precesses, or wobbles like a top as it slows down. So when the saros cycle reaches its culmination, the sun, Earth and moon are almost (but not exactly) in the same relative positions. If the eclipses are taking place near a descending node (as are the eclipses of saros 136 and those of all even-numbered saros cycles), then they will begin as partial eclipses near the Earth's south pole, and gradually shift northward. When they are near the equator (as is the July 2009 eclipse), they are total eclipses and totality lasts longer. Eventually they return to partiality near the north pole and the cycle ends when the moon's shadow no longer reaches the Earth. Here is a page with information about the eclipses of saros cycle 134, which began in 1360 with a partial eclipse in the southern hemisphere, and will end 1262 years later in 2622 with a partial eclipse in the far north. The July eclipse is one of 71 total for this cycle. The animation link on this page is especially cool. http://eclipse.gsfc.nasa.gov/SEsaros/SEsaros136.html

What sorts of unique phenomena take place during a total solar eclipse? To mention a few: as the moment of totality approaches, so does the moon's shadow, rushing toward you from the horizon at 3000 km/hr (1800 mph). This is most easily seen at sea. Just before or just after totality, you may see the last bit of the sun's disc shining through a lunar valley, creating what is sometimes called a "diamond ring" effect. And during totality itself, the outer atmosphere of the sun called the corona, too dim to be seen otherwise, glows a ghostly white. The temperature will drop noticeably, and some of the brighter stars will be visible.

The closest I have ever come to seeing a total solar eclipse was in May of 1984, when an annular eclipse occurred very near Lynchburg. Some of you may remember that as well. It has been a long-time desire of mine to witness a total solar eclipse, and to do so at sea. Several years ago, I began looking at future eclipses for a likely candidate. There are tour companies devoted to taking eclipse chasers all over the world in pursuit of totality, and I contacted the best known of these in 2002. "What are your plans for the July 2009 eclipse?" I asked. I'm sure they had fun passing that e-mail around, but they very politely answered that they generally announced their plans two years in advance, and that I should check back in oh, say-five years? In May 2007, they began taking reservations, and their 320 spaces aboard the ship sold out in two weeks.

Yes, my wife and I are going. It's just a tough break that we have to go to Tahiti and the Cook Islands to do so, and that we will celebrate our 35th anniversary while we are there. But it's a sacrifice I'm willing to make for sake of science. Yes, we will take lots of pictures, and I will share as much of that experience as I can with the readers of these newsletters when we get back.

Other Earths

I remember very well when I was a kid reading every astronomy book available in our school library. Our town was too small for a public library, but in the east Texas oil fields, one of the main employers was Pure Oil-an oxymoron if there ever was one. Pure Oil didn't like paying taxes, but they wanted a good public school system for their employees' families, and the library was fairly well stocked. One of the topics that fascinated me most had to do with how the planets of our solar system might have formed.

There were two main competing models, even though there were then serious problems with both of them. In one, a passing star pulled material from our sun which then condensed into planets. The fact that the sun and the planets are all of the same age speaks to a common origin, however, not some subsequent chance encounter. And as we learned more about the distances between the stars, the unlikely nature of such a near-miss became more apparent. To give you some sense of scale: if our sun were a grain of salt, the next nearest star would be over eight miles away. I would say that the salt grain is safe in its isolation.

The other theory (actually several different ones that share basic characteristics) had the planets forming in a disk around the newly condensing sun. No one was quite sure how that happened, and there are still details that we don't fully understand, but this is the currently accepted model of planetary formation.

The "passing star" hypothesis would make our planetary system unique, or at best very unusual. The so-called "solar nebular" model, however, might be duplicated in other star systems. There was really no way of deciding between the two when your elementary-school-aged author was reading about them.

But there really was. If there is any trend in astronomy, it is one of forcing humility on the human race, of moving it from the center of creation to a (physically, at least) peripheral location. Copernicus showed us that the Earth was not the center of the universe in 1543. Harlow Shapley in 1920 demonstrated that our sun was not at the center of the universe, but was about halfway out from the center of the group of stars we call the Milky Way. And Edwin Hubble in 1925-yes, that Hubble, the telescope guy-showed that even the Milky Way Galaxy was only one of billions of similar galaxies, vast "island universes" of billions of stars, silently flying apart due to the expansion of space-time. We are not at the center. There IS no center. So why should we expect that the processes that formed our planets were unique to us?

In 1995, the first planet orbiting another star was found. I have written before about the most widely-used detection technique, the radial velocity method. A massive planet orbiting close in to its star will pull the star to and fro as it orbits; the two of them actually orbit a common center of mass. As the star moves toward us, its light is blue-shifted, and as it moves away, the light is red-shifted. This is how the vast majority of the well over 300 extra-solar planets have been found.

This is not the way to find another Earth. The method works best with really big planets (super Jupiters) orbiting really close to their stars (much closer than Mercury orbits the sun). These are not the sorts of places where we would find water oceans and Earth-like environs. In fact, the method would have a hard time detecting any planets at all around our sun.

There are other methods as well. One of the most exciting is the transit method, where a planet passes in front of its star as viewed from Earth. This will cause the apparent brightness of the star to dim slightly, and the amount of dimming can give us the size of the planet. If we follow this up with the radial velocity method described above, we can determine the planet's mass. Put the two together, and we have its density, a good measure of whether the planet is rocky like the Earth (high-density), or gaseous like Jupiter (low-density).

We can study the atmosphere of the transiting planet by analyzing the light from its star as it passes through. The presence of water would indicate the potential for Earth-like life; the presence of oxygen-well, that would be absolutely stunning. Oxygen is a chemically reactive molecule that easily combines with surface minerals and must constantly be renewed in our atmosphere. The presence of oxygen in our atmosphere, to the tune of 21% of the total, is due entirely to the life that covers our planet.

We can also determine the planet's temperature. When the planet passes behind its star, only the radiation from the star itself remains. The difference between this and the total radiation when the planet is visible allows us to determine the planet's temperature.

All of these-planet detection, analysis of atmospheric components, temperature determination-all of these have been done for planets orbiting stars that are light years from Earth.

But if you've thought about this a bit, you have probably realized that we must be lined up exactly right to be able to see such a transit, and that most planetary systems won't be so fortuitously arranged. The chance that Earth would be lined up just right for some extra-solar astronomer would be only 0.47%, about 1 chance in 215.

Large numbers to the rescue! An unlikely detection becomes very likely if you look at enough stars. The recently launched Kepler spacecraft (http://www.nasa.gov/mission_pages/kepler/main/index.html <http://www.nasa.gov/mission_pages/kepler/main/index.html> ) will look simultaneously at over 100,000 stars in a fixed field of view, measuring their brightness every 30 minutes, for the next 3-4 years. Think of what that 1 in 215 probability means when applied to 100,000 stars. Assume they were all identical to our solar system, with twins of Earth orbiting twins of our sun. Kepler would discover 465 Earths.

It will happen soon-you'd best get ready for a fresh dose of humility. And when that report of a planet about the size of Earth, with a temperature that would allow liquid water to exist, and with oxygen detected in the atmosphere-when that comes in, get ready to change how you think about life in the universe.

Save Those Old Computers!

A story about the perils of getting rid of those ancient computers: 40-year-old images of the lunar surface sent back by unmanned spacecraft have recently been played back on the original hardware and then upgraded to today's digital standards. Doing so has revealed levels of detail not seen in the original images. The data were there, they were simply inaccessible to older equipment. But the key lesson apparently is that without the original playback hardware, that information would have been lost forever.

http://www.space.com/scienceastronomy/090331-st-moon-views-makeover.html

Play With Pictures from Mars!

If you ever need an example of the amazing age in which we live, consider this. Images of the surface of Mars are provided each day by two surface rovers at two different locations on the planet. These are made available on the internet in near-real time to anyone. These images are raw, uncalibrated, compressed-to put it simply, they are not yet ready for prime-time. Yet a dedicated band of amateurs often processes these images and provides color mosaics overnight. Steve Squyres, the Principal Investigator for the twin Mars Exploration Rovers Spirit and Opportunity, has said, "Frequently I'll get up in the morning and the first place I go online is unmannedspaceflight, because I know I'm going to get mosaics rather than just raw images [that I would get] if I go through all the firewalls to JPL [Jet Propulsion Laboratory], because nobody in Pasadena has even woken up yet." The web site he is referring to is http://unmannedspaceflight.com.

This is not a site for the casual browser. If you are familiar with sites like this, you won't need any instruction from me; if you are not, it would take more space than I have! Sorry. But just to give you some idea of the cool stuff available, here is an image that made the cover of Aviation Week and Space Technology in November 2005. This is NOT a NASA image-this was created entirely by dedicated space and computer geeks. Let's hear it for the folks who truly run the world! And I know that description fits some of the readers of this newsletter. Go to it, y'all.

http://www.aviationnow.com/media/pdf/spirit_p618f_col_a2b.pdf

(I freely admit to stealing this topic (as well as the Steve Squyres quote above) from an article in the January/February Planetary Report, the publication of the Planetary Society. I have plugged them before, but there is simply no better source of information about the solar system, and no better way to support the sorts of activities they describe, than to become a member. http://www.planetary.org)

Saturn in 2009

Saturn has become more easily visible to the vast majority of people unwilling to get up after midnight to see him. Shortly after dark, the second largest planet in our solar system is fairly high in the southern sky. Here is a finder chart created for March, but which will still be good for mid-April. Just shift everything a little to the west and it will work fine for 9 or 10 p.m.

http://transientsky.files.wordpress.com/2009/03/saturn_allsky_09452.png?w=455&h=297

Saturn is bright and somewhat yellowish in appearance. It is already past opposition for this year, the point at which it is opposite the sun in our sky and therefore visible throughout the night. The diagram below illustrates the relative positions of the sun, Earth, and Saturn at opposition in March, and at conjunction in September (when the sun and Saturn are conjoined from our point of view).

http://www.areavoices.com/astrobob/images/Saturn_opposition.jpg

Saturn moves only slowly relative to the background stars because it is moving around the sun much more slowly than the Earth. We lap it repeatedly, orbiting the sun almost 30 times for every one revolution by Saturn. Last year at this time, Saturn was on one side of the constellation Leo; this year it is on the other side of the same constellation. From the same source as the previous image (AstroBob, a superb astronomy blog to which I can only aspire, found here: http://www.areavoices.com/astrobob/), a diagram to illustrate:

http://www.areavoices.com/astrobob/images/Saturn_orbit_in_zodiac_1.jpg

Saturn's famous rings change their appearance during this 30-year cycle, also. Right now they are tilted only slightly relative to us, but on September 4 of this year, they will disappear from view as they orient exactly edge-on. This happens twice in every Saturnian year, every 14 or 15 of our years. It is an illustration of the extreme thinness of the rings. Made up of countless particles of ice ranging from 1 centimeter (0.4 inches) to 10 meters (33 feet) in diameter, they are broad enough to be seen over almost a billion miles of space, yet are probably only about 10 meters thick. Imagine being an astronaut co-orbiting in these rings. You would be moving around Saturn at the same speed as the particles, and could literally climb and "swim" your way from one side of them to the other. What a spectacular view that would be!

Until then, we will content ourselves with this video taken by the Hubble Space Telescope of a rare transit of Saturn by four of its moons. This only occurs when the rings are nearly edge-on, as the moons and the rings all orbit in the same equatorial plane. When Saturn's rings are more highly tilted, the moons appear to pass above or below the face of the planet. This link will let you choose the format and resolution that suits you best, and provides a brief explanation of what you are seeing: http://hubblesite.org/newscenter/archive/releases/2009/12/video/a/

The New Worlds

In 1608, a little over 400 years ago, a rather obscure spectacle maker named Hans Lippershey was supervising the work in his shop. Glass lenses had been known since medieval times to magnify nearby objects. Monks had cut glass spheres in half to create "reading stones" by which they could more easily illuminate manuscripts. Gradually came the realization that shallower lenses would magnify more, and spectacles are known to have been worn as early as 1300 in Italy. Those of us who are over 40 can well appreciate what a blessing these spectacles must have been to those whose eyes could no longer focus well to read. A blessing at least to the few of the time who had lived that long, and who were literate.

The story goes that some children were playing with the lenses in his shop when one held one lens up in front of the other. "Look, master!" he cried, and showed Lippershey how a church steeple in the distance appeared much closer. Lippershey applied for the first patent on a telescope. (He was turned down-the design was deemed useful, but too easy to copy.) He tried equally unsuccessfully to sell it to the Dutch army. His design could magnify only three times.

Soon, however, others had in fact copied the device, and it was showing up in shops and markets all across Europe. In May of 1609, word of the device reached an Italian university professor named Galileo Galilei. Unlike the lavishly compensated professors of today, he was looking for ways to supplement his salary. He taught himself to grind and polish lenses, devised ways to test the lens's curvature and magnification, and by August had a telescope that magnified eight or nine times. He demonstrated the device to the political leaders of the Venetian Republic (his employer), and showed how ships invisible to the naked eye could be seen far out to sea. The obvious military and commercial advantages led them to reward Galileo with a contract extension and a more than doubling of his salary.

It was then that he took the step that revolutionized our view of the cosmos and of our place in it. He turned this new instrument to the night sky.

The moon, thought to be smooth, was revealed to have deep craters and high mountains. By tracking their shadows, Galileo was able to determine their depths and heights. The moon was a world like the Earth, at least in some ways. The heavens weren't a different realm after all. Venus was seen to go through phases, like the moon. The only sensible explanation for this was that it revolved around the sun rather than the Earth. Jupiter had four moons (forever after known as the Galilean moons) that revolved around it. Neither the Earth nor the sun was the sole center of revolution in our solar system. And Saturn-well, something was odd about Saturn. Galileo's telescopes weren't good enough to quite make out what that was, and it was only later that others using better instruments were able to distinguish the ring structure of this planet.

Galileo would ultimately run afoul of the ecclesiastical authorities, partly due to his somewhat abrasive nature, and would spend the last years of his life blind and under house arrest. But late 1609 and early 1610 afforded him vistas seldom revealed to any human being. Those of us who have carried out scientific research at some point in our lives know the thrill that comes from learning something new, from being, at least for a little while, the only person in the world who knows this particular thing. Of course, this is usually something that only a few dozen other people in the world actually care about, at least in my case. Galileo, excuse the expression, rocked our world. It has not been the same since. Imagine, if you can, being the first person ever to see the things he saw.

2009 is the International Year of Astronomy (http://www.astronomy2009.org/), in celebration of the 400 years since Galileo first turned his instrument to the sky. We plan to participate with the Lynchburg College Belk Observatory, and will be letting faculty and staff here at LC know about some planned events very soon.

Last week, my son and I were at the observatory to do some work, and some sightseeing as well. Venus is the very, very bright object high in the southwest after sunset, and we turned the Margaret Gilbert telescope toward it to see its fat crescent shape. It is so dazzling through the eyepiece that it is difficult to see detail-the clouds that cover its surface reflect a lot of light, and are pretty much featureless. But I remembered that we had recently purchased a filter that transmits only ultraviolet light (the little that gets through our atmosphere), and in that wavelength of light, the featureless clouds acquire a bit more character.

A much dimmer (but still easy to see) Venus emerged: one whose light/dark boundary was a bit ragged, a three-dimensional object instead of a flat-looking cutout, an object that looked, well, like a planet. When I find myself envying Galileo for his first-ever views, I have to remember that it is he who would envy me for the marvelous sights our telescope can bring to us.

Christmas at the Moon

Forty years ago this Christmas Eve, three American astronauts were orbiting the moon for the first time in human history.

1968 was a momentous year, the kind of time that produces numerous books with that date as part of the title. Even those of us who were callow high school graduates/college freshmen knew that there were more than the usual number of events that would be remembered for a long time. Most of those events were not happy ones. Assassinations, riots: I recall distinctly urging my then-girlfriend not to give up on America even as I struggled with that impulse myself.

Apollo 8, the mission that sent Frank Borman, Jim Lovell, and Bill Anders around the moon, has been eclipsed in cultural memory by the Apollo 11 moon landing, and by the "successful failure" mission of Apollo 13. If you want to be remembered, have Ron Howard make a movie about you! Indeed, if the average person knows anything about Jim Lovell, it is probably that he was played by Tom Hanks in that movie.

To me at least, Apollo 8 represented a larger leap from what preceded it than Apollo 11. For the first time, human beings escaped the Earth's gravitational influence. For the first time, human beings looked back on the Earth as a whole planet that they could cover with a thumb. For the first time, human beings looked down on a battered and utterly alien world from a distance of only 70 miles.

What many of us remember most, though, happened on Christmas Eve. As a black-and-white TV camera relayed pictures of the moon's surface sliding under the spacecraft's window, the three crew members took turns reading from the first ten verses of Genesis, the creation story. It was incredibly moving to see those images and hear those words. I was visiting with relatives for the holidays, and I remember very distinctly stepping outside, looking up at the half-lit moon in the sky, and telling myself that there were three men up there. It is still something that fills me with wonder.

Jim Lovell, among the most good-natured of all the astronauts, described one congratulatory telegram that stood out from all the rest. It read simply, "Thank you for saving 1968."

There are no really high-resolution movies that I have found of this broadcast, but the impact can still be felt even with the low-quality images available. NASA's page, with both small and large-image video, is here: http://nssdc.gsfc.nasa.gov/planetary/lunar/apollo8_xmas.html. The iconic photograph of "Earthrise" taken by Bill Anders is the other most-remembered item.

http://www.math.montana.edu/frankw/ccp/cases/Global-Positioning/round-earth/earthrise.gif

An excellent account of this (an excerpt from his book "Boom") by Tom Brokaw is here: http://www.newsweek.com/id/69585/output/print. For an idea of what the astronauts saw, go here: http://space.jaxa.jp/movie/20080411_kaguya_movie01_j.html This is a movie taken by a Japanese satellite in orbit around the moon. Yes, these are real images.

Potpourri of Space News

Rather than risk leaving out something of interest, I am listing several short items with links for those who would like to read more detail.

· For my money, the very best blog about solar system matters is maintained by Emily Lakdawalla at this site: http://planetary.org/blog/. Her two most recent posts concern new evidence for ice glaciers on Mars, and a status review of current interplanetary missions.

· While we are on the subject of web sites you should bookmark (We were, weren't we?), the Astronomy Picture of the Day (http://antwrp.gsfc.nasa.gov/apod/astropix.html) should be at the top of the list for anyone interested in beautiful and fascinating images.

· If you have some 3D glasses (I just happen to have a pair sitting on my desk; evidence if it were ever needed of my charter membership in the Society of Nerds), you can take advantage of these new image pairs taken from Mars orbit: http://hirise.lpl.arizona.edu/anaglyph/index.php

· In 1572, 37 years before the invention of the telescope, Tycho Brahe observed a "new star" where none had been seen before. It was bright enough to be visible in the daytime for several weeks, and only faded from night time visibility over many months. We have known for some time that it was a supernova; the question was-what kind? We now have some answers: http://www.timesonline.co.uk/tol/news/uk/science/article5282644.ece

· Mars Science Laboratory, the next planned mission to Mars, has been postponed. Originally scheduled for launch late in the summer of 2009, it has been delayed until late in 2011. Even though the project is a few months behind schedule (not two years behind), Earth and Mars are favorably aligned for launch only every 26 months; the next launch window closes too soon, and the one after that does not open until two years later: http://features.csmonitor.com/innovation/2008/12/04/nasa-delays-mars-science-laboratory-launch-to-2011/

· The Hubble Space Telescope continues to provide us with breathtaking images. One of the latest is of the heart of M13, a globular cluster located about 25,000 light years away from us. M13 is an easy object for even small telescopes, and one guaranteed to draw gasps from viewers seeing it for the first time. But of course this level of detail is only seen with an instrument like the Hubble: http://hubblesite.org/newscenter/archive/releases/2008/40/. For those of you who won't refuse to click on a Wikipedia link, here is a very good and comprehensive article about globular clusters: http://en.wikipedia.org/wiki/Globular_cluster.

· Water vapor has been detected in the atmosphere of a planet orbiting a star 63 light years away. Just pause for a moment to let that last sentence sink in. http://www.space.com/scienceastronomy/081210-exoplanet-water-vapor.html

Night Sky Happenings

The two brightest planets are both visible shortly after sunset, and will be moving closer to each other in sky in the next few weeks. The one closer to the Sun in the southwest is Venus; the one farther east is Jupiter. On the nights of November 30th and December 1st, they will appear very close to each other, and on the night of the 1st, they will both be very near the crescent moon. A beautiful sight! Of course, the actual three-dimensional distances are quite different. The moon is nearest us, followed by Venus and then by Jupiter. But on these nights, they appear to us to be nearest neighbors.