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Journal of the Amateur Astronomers Association of New York December 2008 Volume 56 Number 12, ISSN 0146-7662

EYEPIECE

Dispute Flares on Going to the Moon or Mars First
By Dan Harrison
Answering a question followin g h is Novem b er 21 lecture to the AAA on a 2006 mission to service the ISS, Coast Guard captain and former astronaut Daniel C. Burbank was clear in saying humans should return to the Moon before they go to Mars.
"Mars possibly has fossilized want to look from the quiet back Moon can be easier supplied and correct. You can't fabricate things If we're and "there where we' of a better life, but astronomers side of the Moon. The problems are easier to on the space station."

Mars may hold the answers to the "fundamental question" of whether we are alone.
No sooner was the ink dry on t h e societ y's proposal than ex-astronaut Harrison Schmitt strongly attacked it and resigned from the society. He said returning to the Moon is the fastest and most cost-effective path to Mars for the following reasons, among others: "We need generations of engineers to relearn how to operate in deep space for long durations on a location more accessible than a trajectory to Mars or on Mars. "We have no clear technology approach for landing large payloads on Mars. Developing entry, descent and landing concepts and testing them in the upper atmosphere will be a major program in and of itself, with uncertain cost and duration. "Knowing whether 1/6thg triggers human readaptation from the adverse consequences of 0g is critical to the design and mass of both Mars transportation systems and Mars surface operations. "Many concepts required for operations on Mars need testing in a real-world deep space environment before committing to using them in Mars exploration, including autonomous crew operations during entry, descent, landing and real-time exploration without communications Dispute flares continued on page 8

going to go to Mars, it will take 26 months, have never been 26 days on the space station ve not been surprised." He said he can't think place for science than the Moon.

Burbank's strong assertion t h a t t h e M oon sh ou ld come before Mars squares with NASA's plan. But last month, the Planetary Society urged that Mars come first. Society officials outlined a plan that would focus on Mars as the driving goal of human spaceflight, deferring landing on the Moon until costs of the interplanetary transportation system and shuttle replacement are largely paid. The society also advocated a step-by-step approach of new achievements in interplanetary flight, including a human mission to a near-Earth object. "For human exploration, Mars is clearly the next crucial goal. Lunar exploration can be an intermediate step towards that goal, but care needs to be taken that it not absorb too many resources and become the end goal. "Returning to the Moon h a s n ot su fficien t ly excit ed the public, and will require resources that will be badly needed elsewhere in the space program." In addition,

AAA to Move to New Headquarters Renew Your Membership Now!
See President's Letter on Page 3 --------------------


What's Up
By Tony Hoffman The Sky for December 2008
Observe Exoplanet Suns! Alt h ou gh t h e p la n et s r ecently photographed, in an astronomical first, near the stars Fomalhaut and HR 8799 are far too faint to be observed, their parent suns are readily visible at this time of year. Early on fall evenings, when I take a walk around my Queens neighborhood to have a look at the stars, I make a point of looking to the south for Fomalhaut, the southernmost first-magnitude star visible from New York. It's the brightest star in Piscis Austrinus, the Southern Fish. The star's name is Arabic, meaning mouth of the fish. In 1983, Fomalhaut gained a measure of celebrity when the Infrared Astronomical Satellite discovered a dust ring--a solar system in the process of formation--surrounding this hot, young star. Now Fomalhaut is right up there with Brangelina in notoriety after astronomers led by Paul Kalas at UC Berkeley found a planet orbiting at the inner edge of the dust ring in Hubble photos from 2004 and 2006. I'm sure I'll feel a special thrill whenever I see Fomalhaut from now on. You can see it, too. Around December 1, it's due south, about 20 degrees above the horizon, at 6:20 p.m. It twinkles white and alone in a large, star-bare patch of sky. Catch it early, as it will quickly sink into the southwest. And catch it soon, as it will become lost in the solar glare early in the new year. Meanwhile, Pegasus rides n ea r ly over h ea d a s t h e sky darkens. Another group of astronomers recently imaged three worlds with masses of between 5 and 13 Jupiters orbiting HR 8799, a star just within the Great Square. At about 6th magnitude, the star is easily visible in binoculars. Curiously, it lies only 2.3 degrees from 51 Pegasi, the star around which the first exoplanet was (indirectly) detected in 1995. These stars can be seen within the same binocular, or low-power telescopic, field of view. Decem Decem Decem Decem gee.
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December December December 7:04 a.m. December December December December December

13 G em in id m et eor sh ower p ea k s. 18 M oon lies n ea r Sa t u r n . 19 L a st -quarter Moon; Winter Solstice at 22 25 27 28 29 Ur sid m et eor M oon lies n ea New M oon a t M oon lies n ea M oon lies n ea sh ower p ea k s. r An t a r es. 7: 22 a .m . r M er cu r y. r J u p it er .

Two planet-bearing suns, HR 8799 and 51 Pegasi, lie within the same low-power field of view in Pegasus.

Mercury and Venus Emerge
By Joseph A. Fedrick
Mercury briefly emerged fr om t h e sola r gla r e in late October to enter the predawn morning sky. It appeared far east of Saturn, barely clearing the tree line to my east on the morning of October 27 at 7:10. Mercury appeared pale tan and gibbous at 100x in my 60 mm refractor. Venus began to emerge from the solar glare and the bright evening twilight to become more prominent during October. It still hugged the horizon, though, and set soon after the Sun during October. By October 30, Venus had closed to just over 30 degrees west of Jupiter. Like Mercury, Venus appeared gibbous, although Venus presented a fuller gibbous phase than Mercury did in my 60 mm refractor at 50x. By November 10, Venus had closed to within approximately 20 degrees of Jupiter. Venus and Jupiter were already beginning to appear as an awesome pair even before a close approach of approximately 2 degrees on November 30 and December 1.

ber ber ber ber

1 M oon lies n ea r Ven u s a n d J u p it er . 4 Ast er oid 2 P a lla s a t op p osit ion . 5 F ir st -quarter Moon at 4:26 p.m. 12 F u ll M oon a t 11: 37 a .m .; M oon a t p er i-


A Message from AAA President Richard Rosenberg
Hello, members: The big news is we have a new headquarters! Beginning in February at the latest, we 'll be at the Downtown Community Center at 120 Warren Street. Located in a new building, the center is a non -profit organization providing services to the residents of lower Manhattan in particular and to the New York metropolitan area in general. It has a newsletter reaching thousands of families, and our events will be listed. Most important, the center has all the modern amenities that will enable us to enhance our meetings with Power Point presentations, videos, planetarium programs and access to the internet. Our rent will be lower than what we currently pay.

The observers' group will be the first club activity to move to the center. It will be held on a weeknight (not yet determined) from 7 to 9 p. m. If you're interested in attending, let me know which day of the week you prefer. The observers' group will have a new format: After the meeting, we'll head to the nearby Hudson River to do some observing.
We expect to hold board meetings and the annual meeting at the center. In fall 2009, we'll add more events, reinstating our class and possibly adding another meeting of our seminar to the one now held at NYU. The Park Avenue Christian Church has served the club well for many years and we wish them all the best. But we feel the move will better enable us to bring astronomy to the public. Special thanks to Alice Barner, who informed me of the center and helped to arrange meetings with the center's management.

I have appointed Jason Kendall to our board of directors. Jason is a sidewalk astronomer in Inwood who is out several nights each week. He's also involved in the 100 Hours of Astronomy project (http:// www.100hoursofastronomy.org/).
At the board meeting November 19, we discussed sending Ey epiece via e-mail to members who wish to receive it that way. Marcelo Cabrera will look into the technical requirements. Custer Institute has made the club an offer of free space for an observatory, which we would supply. Tony Hoffman will check out the possibility of a club observatory. I have signed the contract with the Solaria condominium in Riverdale to provide support for its telescope and host four observing sessions and lectures a year. In return we'll have 65 new members, one for each apartment. We still have copies of the "2009 Observers Handbook" from the Royal Astronomical Society of Canada for the bargain price of $17.45 ($20.67 if you want it mailed to you). Get in touch with me. First come, first served. Finally, let me remind you that this is renewal time. If you send in your $25 membership fee now, you'll save us the effort and cost of mailing a solicitation to you. Plus you can get A stronom y and/or S k y & T elescope magazine at sharply reduced rates, $34 one year or $60 two years for A stronom y , $32.95 for S k y & T elescope. Send your check to the Amateur Astronomers Association, Box 383, Gracie Station, New York, NY 10028. Thank you. Rich Rosenberg, AAA President, president @aaa.org, (718) 522-5014
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Review: A Book for the Kid(s) on Your Holiday List
By Mary Carlson
Brian Greene, in his children's book "Icarus at the Edge of Time" (Knopf, $19.95), introduces young readers to a 14-year-old boy in his quest for immortality. As we join families and crew of a six-generational starship, the Proxima, we meet our space age passenger, Icarus. The Proxima is the only home he, his father and grandfather and subsequently his heirs will ever know. They're on a multigenerational journey from Earth to the Proxima Centauri star system. Yet life is pretty mundane for our precocious teenager, who yearns for adventure beyond his predetermined future. When the Proxima unexpectedly encounters a forbidding black hole, Icarus is hooked! Dismissing all warnings from father and crew of the gravitational perils of a black hole, he sets out in his uniquely designed Runabout to explore the behemoth. Like his Greek counterpart who flew too close to the Sun, Icarus charts a fateful course to graze the beckoning event horizon. Both likes and dislikes of the book were unanimous among all age groups. All wished the book had illustrations of the Proxima, the Runabout and the later starships. However, all were "pulled in" with the depiction of the black hole as it visually loomed larger and larger as the story progressed. All were intrigued with the masterful background depictions of blazing nebulae, spectacular galaxies, pulsating stars and a remarkable supernova. Much time was spent on discussing these phenomena: what they are, how they came to be, how far away they are. Although the appeal was mostly t o old er ch ild r en in the group, Greene seems to have succeeded in igniting young imaginations. Several children wanted to bring the book to school for the class and/or teacher to read. Its provocative story line, highlighted by great illustrations, makes it a book to be owned, not borrowed.

Seminar Scoops T he T im es!
On Thursday, November 13, in t wo sep a r a t e d iscoveries, the astronomy world was thrilled by the first visual confirmation of extrasolar planets long sought by scientists. NASA reported that with Hubble's enhanced capabilities, it took the first visible-light picture of a planet circling another star. The star is Fomalhaut in the constellation Picis Australis It and the planet, Fomalhaut b, are 25 light-years from Earth.
Online images showed scratchy Gemini and Keck telescope pictures of a three-planet system around star HR 8799 in Pegasus, 130 light-years away. These are the first pictures of an entire system. Prior to these two discoveries, the 300-plus exoplanets discovered were due to host-star wobbles or periodic dimming. The planets were presented wit h visu a ls a n d d iscussed at length at the November seminar that evening. The story appeared on the front page of T he N ew York Times the following da y. Want more information? Join us at the seminar Thursday, December 11th at 6 p. m. See page 11 for details.-Mary Carlson, Chairman, Recent Advances Seminar

After five successful treks a r ou n d t h e ed ge of t h e black hole, he heads back to the Proxima for congratulatory honors. He's the first human to successfully navigate an event horizon and report back on its mysteries. But at the last coordinates, the mother ship is nowhere in sight. Instead, he finds himself in the middle of an interstellar highway. Hundreds of enormous starships of strange designs hurtle by at warp-plus speeds. "How can this be? Where is my family?"
Hundreds of possibilities wander through Icarus' mind. Then comes the unbelievable realization. For all his expert piloting and careful calculations, he neglected to account for gravity and time. Yes, he'd successfully grazed a black hole, but in the process, he'd been propelled 10,000 years into the future. "Wow!" "How come?" and "Awesome" were comments from my young listeners. The four-year-olds in the group quickly lost interest (except for the black hole itself) while the six-year-olds liked the tale but weren't quite sure about the ending. With the eight-year-olds, the story sparked what ifs, comments and suppositions. It seemed to put imaginations in high gear.
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National Geographic Discusses Our Vanishing Night
Last month's Na tiona l Geogr a phic cover story, "Our Vanishing Night," discussed how most city skies have become virtually empty of stars. An abridged version of the article, by Verlyn Klinkenborg, follows. If humans were truly at home u n d er t h e ligh t of the moon and stars, we would go in darkness happily, the midnight world as visible to us as it is to the vast number of nocturnal species. Instead, we are diurnal creatures, with eyes adapted to living in the sun's light. This is a basic evolutionary fact, even though most of us don't think of ourselves as diurnal beings. Yet it's the only way to explain what we've done to the night: We've engineered it to receive us by filling it with light. This kind of engineering [has] benefits [that] come with consequences--called light pollution--whose effects scientists are only now beginning to study. Light pollution is largely the result of bad lighting design, which allows artificial light to shine outward and upward into the sky, where it's not wanted, instead of focusing it downward, where it is. Ill-designed lighting washes out the darkness of night and radically alters the light levels-and light rhythms--to which many forms of life, including ourselves, have adapted. Wherever human light spills into the natural world, some aspect of life--migration, reproduction, feeding--is affected. Most of humanity lives under intersecting domes of reflected, refracted light, of scattering rays from overlit cities and suburbs, from light-flooded highways and factories. Nearly all of nighttime Europe is a nebula of light, as is most of the United States and all of Japan. In most cities the sky looks a s t h ou gh it h a s b een emptied of stars, leaving a vacant haze that mirrors our fear of the dark and resembles the urban glow of dystopian science fiction. We've grown so used to this pervasive orange haze that the original glory of an unlit night--dark enough for Venus to throw shadows on Earth--is wholly beyond our experience. And yet above the city's pale ceiling lies the rest of the universe, utterly undiminished by the light we waste--a bright shoal of stars and planets and galaxies, shining in seemingly infinite darkness. We've lit up the night as if it were an unoccupied country, when nothing could be further from the truth. Among mammals alone, the number of nocturnal species is astonishing. Light is a powerful biological force, and on many species it acts as a magnet. The effect is so powerful that scientists speak of songbirds and seabirds being "captured" by searchlights on land or by the light from gas flares on marine oil platforms, circling in the thousands until they drop. Migrating at night, birds are apt to collide with brightly lit tall buildings; immature birds on their first journey suffer disproportionately. Insects cluster around streetlights, and feeding at those insect clusters is now ingrained in many bat species. Other nocturnal mammals for a ge m or e ca u t iou sly under the permanent full moon of light pollution because they've become easier targets for predators. Some birds sing at unnatural hours in the presence of artificial light. Scientists have determined that long artificial days--and artificially short nights--induce early breeding in a wide range of birds. And because a longer day allows for longer feeding, it can affect migration schedules. The problem is that migration, like most aspects of bird behavior, is a precisely timed biological behavior. Leaving early may mean arriving too soon for nesting conditions to be right. Nesting sea turtles, with a natural predisposition for dark beaches, find fewer to nest on. Their hatchlings, which gravitate toward the brighter, more reflective sea horizon, find themselves confused by artificial lighting behind the beach. Frogs and toads living near brightly lit highways suffer nocturnal light levels as much as a million times brighter than normal, throwing nearly every aspect of their behavior out of joint. Of all the pollutions we face, light pollution is perhaps the most easily remedied. Simple changes in lighting design and installation yield immediate changes in the amount of light spilled into the atmosphere and, often, immediate energy savings. It was once thought that light pollution only affected astronomers, who need to see the night sky in all its glorious clarity. In fact, some of the earliest civic efforts to control light pollution--in Flagstaff, Arizona, half a century ago--were made to protect the view from Lowell Observatory, which sits above that city. Flagstaff has tightened its regulations since, and in 2001 it was declared the first International Dark Sky City. By now the effort to control light pollution has National Geographic continued on page 10
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Briefs: Two Systems Provide First Direct Exoplanet Images
Astronomers have taken what they say are the first direct images of planets outside our solar system, including a visible-light snapshot of a single-planet system and an infrared picture of a three-planet system. The single newfound planet, via Hubble, orbits Fomalhaut, which is visible without a telescope. The three sister planets are each much heftier than Jupiter. Until now, scientists have inferred the presence of planets mainly by detecting an unseen world's gravitational tug on its host star or waiting for the planet to transit in front of its star and then detecting a dip in the star's light. The trio of worlds, via Gemini and Keck, orbits HR 8799, 130 light-years away in Pegasus and about 1.5 times as massive as the Sun. The planets are at distances from their star of 24, 38 and 68 AUs. Other planet-finding techniques work out to about 5 AU from a star. The planet closest to the star is 10 times the mass of Jupiter, followed by another 10 Jupiter-mass planet and then a world seven times Jupiter's heft. The planets formed only about 60 million years ago, so they're still glowing from heat left over from their formation. The most distant planet orbits just inside a disk of dusty debris. Unlike most extrasolar planets already known, HR 8799 has its giant planets in the outer parts and so has "room" for smaller terrestrial planets in the inner parts. The single-planet system, viewed in visible light, has been named Fomalhaut b, and is estimated to weigh no more than three Jupiter masses. Fomalhaut b is 1 billion times fainter than its star. It's about 25 lightyears from Earth. It's thought the planet orbits Fomalhaut every 872 years at a distance of 11 billion miles, four times the Neptune-Sun distance. The end seems to have finally come for NASA' s Phoenix Mars Lander mission at the planet's north pole. Mission controllers lost touch with the lander November 2. The craft had been studying the arctic surface since landing there May 25. Phoenix scooped up samples of dirt and subsurface water ice and analyzed them for signs of past potential habitability. It successfully completed its mission objectives at the end of its primary mission in August. Phoenix's big finding was to confirm the presence of water ice under the surface dirt layer in the northern plains. It also found dirt at the lander's location was more alkaline than the soil sampled by the Mars Exploration Rover missions closer to the equator. Phoenix's measurements also unexpectedly turned up signs of per6

chlorate, a possible source of energy for any potential life that could have once graced Mars. The lander's power supplies had been steadily diminishing in recent weeks as the Sun dips toward the horizon with the approach of fall and winter to Mars' northern hemisphere. Mankind's first up-close photos of t h e lu n a r la n d scape have been rescued from four decades of dusty storage and restored to such a high quality that they rival anything taken by modern cameras. The first image shows the Moon with Earth rising in the background. In 1966 and 1967, NASA sent five lunar orbiters to the Moon to take photos to prepare for man's first visit in 1969. With one photo down, there are 1,983 to go. When NASA launches its next high-tech lunar probe in the spring, it can compare detailed high-res images from 1966 to 2009 and see what changes occurred in 43 years. Nobody knows what dark matter is, b u t scien t ist s may now have a clue where to look for it. A new computer simulation of the evolution of a galaxy like the Milky Way suggests it might be possible to observe high -energy gamma-rays given off by dark matter. This may permit scientists to "see" what dark-matter distribution should look like near the Sun, where there might be a chance of detection. Past studies indicated dark matter was crucial in galaxy formation and it still exists in halos surrounding galaxies. The new simulation examined how these dark matter halos might evolve and behave. The virtual galaxy's halo grew through a series of violent collisions and mergers between much smaller clumps of dark matter emerging from the Big Bang. The simulation revealed gamma-rays produced when particles collided in areas of high dark-matter density could be detectable easiest in regions of the Milky Way lying close to the Sun, in the general direction of the galaxy's center. Volcanic activity on the far side of t h e M oon m a y have lasted longer than thought, new images suggest. This could help shed light on the Moon's formation and evolution. The lunar surface is dead now, but over the years it experienced volcanic activity. Radiogenic dating is the best way to date mineral deposits, but surface samples are limited, and come only from a few locations on the near side. Another way to estimate the age of volcanContinued on page 7


Briefs: Hubble Repair Mission Set No Earlier than May
Continued from page 6 ic features is to count how many impact craters they have: the younger the feature, the fewer the craters marking the surface. Researchers did that for two areas on the far side. Most mare volcanism ceased on the far side about 3 billion years ago, but at a few locations, scientists estimated mare deposits at 2.5 billion years ago. Volcanism also continued on the near side, apparently lasting longer than on the far side. Basalts have been estimated at 1 billion years old. The different termination of volcanic activity on the two sides could be related to a thicker crust on the far side, or fewer heat-producing radioactive elements there. The nature of strange ripples of M a r t ia n sa n d is clearer thanks to new pole-to-pole images. But scientists still are unsure just how the features, unlike anything on Earth, came to be. The ripples, over large swaths of Mars, are smaller than the planet's gigantic dunes but larger than sand-ripple fields on Earth. The unusual features are formed by wind-driven particles. The winds blow the ridges into many shapes. They hold clues to past and present climate processes. The survey of more than 10,000 images showed they're more common in the southern hemisphere, are found in an equatorial belt between 30 degrees north latitude and 30 degrees south latitude, exist near layered terrain or adjacent to Large Dark Dunes and are abundant in the Meridiani Planum region and in southern-latitude craters. Those near layered terrain are generally several million years old and inactive, while others are young and may still be active. Meteorites that are among the oldest r ock s ever found have provided new clues about conditions that existed at the beginning of the solar system. The meteorites still contain magnetic records about the very early history of planets, new research indicates. Analysis showed that surprisingly, during the formation of the solar system, when dust and rubble in a disk around the Sun collided and stuck together to form ever-larger rocks and eventually planets, objects much smaller than planets --just 100 miles across or so--were large enough to melt almost completely. This total melting of planetesimals caused lighter materials including silicates to float to the surface and eventually form a crust, while heavier ironrich material sank to the core, where it began swirling to produce a magnetic dynamo. Traces of magnetic fields produced by that dynamo are recorded in meteorites that fell to Earth. Until recently, it was thought planetesimals that came together to build planets were homogenous, unmelted rocky material, with no large-scale structure. Now it's seen that many were mini-planets themselves, with crusts, mantles and cores. Some meteorites formed just 3 million years after the birth of the solar system and show signs their parent body had a magnetic field 20%40% as strong as Earth's today. Short-lived planetesimal dynamos may have been widespread in the early solar system. The fallout from a major glitch wit h t h e H u b b le h a s again delayed plans to send a space-shuttle crew to overhaul the observatory for the final time, with launch now set for no earlier than May due to problems with a spare part. NASA hoped to launch seven astronauts to Hubble aboard the shuttle Atlantis October 14, but delayed the mission to February after a serious hardware failure prevented Hubble from relaying the bulk of its images and data to Earth. The troubleshooting effort culminated in release of Hubble's first new image since the glitch: a portrait of an odd pair of galaxies called Arp 147. In the image, one galaxy looks somewhat like the number "1" and is relatively undisturbed but for a smooth ring of starlight. It appears nearly edge-on to our line of sight. The other galaxy looks like a zero, exhibiting a clumpy, blue ring of intense star formation. The blue ring was formed after the first galaxy passed through the other. Arp 147 lies in Cetus, more than 400 million light-years from Earth. The final Hubble overhaul is expected to extend the telescope's life through at least 2013. A nearby star, visible wit h t h e u n a id ed eye, is ringed with two rocky asteroid belts and an outer icy halo. The inner asteroid belt appears to be a virtual twin to the belt in our solar system. The presence of the rings of material around Epsilon Eridani suggests unseen planets lurk there. Located 10.5 light-years from Earth in Eridanus, the star is the ninth closest to the Sun. Epsilon Eridani is slightly smaller and cooler than the Sun. While the Sun is an estimated 4.5 billion years old, Epsilon Eridani is 850 million years old. Astronomers had known Continued on page 8
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Briefs: Mars May Have Been Wet Longer Than Thought
Continued from page 7 about the star's outer icy ring, but were surprised when Spitzer revealed the rocky rings between the halo and the star. The inner asteroid belt orbits at 3 AUs from Epsilon Eridani, the same distance as from the Sun to the asteroid belt between Mars and Jupiter. Epsilon Eridani's second asteroid belt is 20 AU from the star, and is crowded with as much mass as the Moon. The outer icy ring, previously observed, extends 35-100 AUs from Epsilon Eridani and is similar in composition to the Kuiper Belt. Eridani's outer ring holds 100 times more material than ours. Scientists say three planets with masses between Neptune's and Jupiter's could be in orbit around Epsilon Eridani. Two moons around main-belt asteroid K leop a t r a 216 have been discovered. They could be fragments resulting from disruption of an asteroid that later gently collided to form a dumbbell-shaped body with dimension of 135 miles by 58 miles by 43 miles. A 3.1 mile-sized moon was seen on the first images of Kleopatra. Additional data revealed a second fainter satellite, 2.9 milesized, closer to the primary. It had been predicted that the rubble-pile structure of the primary, linked with its fast rotation (~5 h), could result in ejection of fragments after an oblique impact that formed satellites. It's also possible these moons are subsequently captured remnants of the catastrophic disruption of the parent asteroid. Mars may have been wet for a b illion yea r s lon ger than previously thought, new water-related evidence suggests. Until now, two major groups of hydrated minerals, phyllosilicates and hydrated sulfates, had been observed. A new hydrate mineral has now entered the picture: hydrated silica, known as opal. These silicates, the youngest of the three types of hydrated minerals, formed where liquid water altered materials created by volcanic activity or meteorite impacts. Identification of opaline silica indicates water may have existed as recently as 2 billion years ago. Some opaline deposits were also associated with iron sulfates, the sort of minerals one would expect to see if Mars had very acidic water. The vast majority of asteroids t h a t com e n ea r E a r t h match only a tiny fraction of the meteorites that most frequently hit our planet. Since meteorites are mostly
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pieces of asteroids, this was hard to explain, but a team from several institutions thinks it has found the answer. The smaller rocks that most often fall to Earth seem to come from the asteroid belt between Mars and Jupiter. The study is good news for protecting Earth. A major problem in figuring out how to deal with an approaching asteroid is they're so varied. But now that this analysis has shown most near-Earth asteroids are of a specific type--stony objects, rich in the mineral olivine and poor in iron--it's possible to concentrate planning on them.

Dispute flares continued from page 1
support from Earth. "We need a heavy-lift launch infrastructure that can support the assembly of large interplanetary spacecraft in Earth orbit, and the requirements to return to the Moon support the development of that infrastructure. "We need to develop a n in t er p la n et a r y p r op u lsion system that allows continuous acceleration and deceleration so the travel time to Mars can be cut significantly. "We need to certify sample collection and protection protocols on the Moon with exposure to lunar dust and polar volatiles as surrogates for micro-organisms or the planetary protection lobby will make sample return from Mars impossible." Schmitt asserted that returning t o t h e M oon fu r t h er enables, in a much more timely fashion than would a Mars initiative, the capability to do something about diverting an asteroid. A report on Burbank's talk to the AAA will appear in next month's Ey epiece.

Contacting the AAA
If you want to join, volu n t eer , p a r t icip a t e in even t s, have a question or change your address, e-mail members @aaa.org, or leave a message at AAA hq: (212) 5352922. Also, visit us on the web at www.aaa.org. If you want to write an article for Ey epiece, contact editor Dan Harrison at editor@aaa.org or (914) 762-0358.


Events on the Horizon December 2008
M: members; P: open to the public; T: bring your telescopes, binoculars, etc.; C: cancelled if cloudy; HQ: at AAA headquarters, 1010 Park Avenue (between 84th and 85th streets); AMNH: For ticket information, call (212) 769-5200 For directions to AAA observing events, check the club's website at www.aaa.org.

Monday, December 1, 5-8 p. m. Observing at Brooklyn Heights Promenade, P, T, C Special observing session to see the Moon-Venus-Jupiter conjunction.
Friday, December 5, 6:15 p. m. AAA lecture, P Prof. David Hogg of NYU will speak on "Automated Calibration of Astronomical Imaging and the OpenSource Sky Survey" in the Kaufmann Theater of the AMNH. Next lecture: January 2.

Prof. Maria T. Zuber of MIT will talk on "Why Return to the Moon?" This presentation will highlight ongoing exploration plans and discuss why a lunar invasion, of sorts, is taking place.
Thursday, December 11, 6-8:30 p. m. Recent Advances in Astronomy Seminar, M NYU, 239 Greene St., Room 801. Next date: January 8. Saturday, December 20, 10 a. m.-noon Solar Observing at Central Park, P, C Conservatory Waters. Next date: January 31. Saturday, December 20, 1-4 p. m. Observers' Group, M, HQ Second of two presentations on asteroids, "Things that Sometimes Hit Us." Next date TBD. Check www.aaa.org or 718-522-5014.

Friday, December 5, 8-10 p. m. Observing at Floyd Bennett Field, Brooklyn, P, T, C Next date TBD.
Monday, December 8, 7:30 p. m. Hayden Planetarium lecture, P, AMNH

NYU Prof to Discuss Archive Containing Amateur Data
Dr. David Hogg, associate professor of p h ysics a t NYU and a member of its Center for Cosmology and Particle Physics, will address the AAA on "Automated Calibration of Astronomical Imaging and the OpenSource Sky Survey" on Friday, December 5. The free public lecture begins at 6:15 p. m. in the Kaufmann Theater of the AMNH. "We have built a number of Web-based and downloadable automated data-calibration and analysis tools which permit anyone with reasonable digital astronomical data to calibrate it for inclusion in scientific projects, archives and distributed virtual collections," Hogg says. "We are using these tools to unite all digital amateur data in the world into an enormous observatory archive, and unite all active amateurs into a responsive, real-time, allsky observatory. This observatory will have some capabilities unmatched by any professional observatory or even network of observatories in existence." Other upcoming AAA lectures are: January 2: Robert Nemiroff, Michigan Technological University, "Best Astronomy of the Day Pictures 2008"; February 20: Joseph Patterson, Columbia, "The Center for Backyard Astrophysics"; March 13: Neil d e G r a sse T yson , H a yden Planetarium, "The Rise and Fall of Pluto--Witness to Demotion" (John Marshall Memorial lecture); April 3: Rick Fienberg, Phillips Academy, "The More Things Change"; May 1: Den t on E b el, AM NH , "The Stardust
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National Geographic continued from page 5 spread around the globe. More cities and even entire countries, such as the Czech Republic, have committed themselves to reducing unwanted glare. Unlike astronomers, most of us may not need an undiminished view of the night sky for our work, but like most other creatures we need darkness. Darkness is as essential to our biological welfare and our internal clockwork as light itself. Regular oscillation of waking and sleep is nothing less than a biological expression of the regular oscillation of light on Earth. Altering these fundamental rhythms is like altering gravity. For the past century or so, we've been performing an open-ended experiment on ourselves, extending the day, shortening the night, and short-circuiting the human body's sensitive response to light. The consequences are more readily perceptible in less adaptable creatures living in the peripheral glow of our prosperity. But for humans, too, light pollution may take a biological toll. One new study suggests a direct correlation between higher rates of breast cancer in women and nighttime brightness of their neighborhoods. In the end, humans are no less trapped by light pollution than the frogs in a pond near a brightly lit highway.

Living in a glare of our own making, we have cut ourselves off from our evolutionary and cultural patrimony-the light of the stars and the rhythms of day and night. Light pollution causes us to lose sight of our true place in the universe, to forget the scale of our being, which is best measured against the dimensions of a deep night with the Milky Way--the edge of our galaxy--arching overhead.

Hayden Debuts New Website
A new Hayden Planetarium website is off and running at http://www.haydenplanetarium.org/. "The site is a bit of an experiment because we are the first [AMNH] department to host a blog and forums," says webmaster Brian Abbott. "Our blog covers several categories including digital universe, night-sky observations and events, ongoing research from AMNH's departments of astrophysics, and earth and planetary sciences, as well as occasional news items about the planetarium. The forums address our digital-universe community, but more forums may be added."

The new features allow participation in conversations between members of the website, which can be done through blog comments and forum posts.

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