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Journal of the Amateur Astronomers Association of New York August 2008 Volume 56 Number 8, ISSN 0146-7662

EYEPIECE
duce light. "With glare, you see less, not more."

State Light-Pollution Bill May Be Split Into Several in '09
By Dan Harrison
The lead State legislation said las overall legislation means of getting at Assembly sponsor of ligh t -pollution t month that separate bills instead of may be introduced next year as a least some measures passed.

Interviewed by Ey epiece, upper west side Manhattan Democrat Linda Rosenthal said the whole bill is being examined. "With light trespass a big concern, that's one example of what can be a separate bill." Light trespass was stripped from the bill this year to help insure passage. But while the Assembly overwhelmingly passed the bill, it never emerged from the State Senate Rules Committee, a fate that has befallen light bills a number of times during the past decade. While Rosenthal said "there could be separate bills if that's the best way to pass all elements," she declined to speculate on the contour of any separate bills other than light trespass possibly being broken out separately. And she underscored that the main element of any attempts to restrict light pollution, no matter how many bills are introduced, would continue to be the push for fully shielded luminaires. Opposition by New York City's Dep a r t m en t of Transportation for cost reasons--and the implied concern about erosion of its authority--has been a big stumbling block to shielded fixtures, but CDOT finally accepted evidence that fully shielded fixtures can match the performance of drop-lens cobraheads currently used. Rosenthal and others have consistently pointed out that shielded luminaires wouldn't have to be installed en masse, but only as replacement fixtures. Rosenthal pointed out that education is also needed to blunt the belief that fully shielded fixtures would re-

Another factor, she noted, is that the city doesn't like the state to tell it what to do. Rosenthal is uncertain whether four light-pollution bills introduced by Councilman Alan Gerson will pass, and if they pass, whether they would affect the outlook for a state bill. "They could reduce the need for a state bill since the greatest need for light-pollution legislation is in the city." Another factor that could affect the outlook for a state bill is the possible takeover of the State Senate by the Democrats. In May, Gerson, wh o r ep r esen t s p a r t of lower Manhattan, got the ball rolling by introducing two of four planned separate light-pollution bills. They require fully shielded light fixtures on city streets and provide performance design criteria for illuminated signs. Of the two other bills, one would mandate interior motion detectors in commercial and government buildings so office spaces during uninhabited hours would automatically shut off their lights. The other would require exterior lights which excessively shine into apartments or offices Light Pollution continued on page 10

Planet Talk Begins Lecture Series Oct. 3
AMNH astrophysicist M or d eca i-Mark Mac Low will begin the AAA's 2008-09 lecture series Friday, October 3 when he discusses "The Puzzles of Planet Formation." AAA lectures, free and open to the public, are at 6:15 p. m. in the AMNH's Kaufmann Theater. Other dates in the series are November 21, December 5, January 2, February 20, March 13, April 3 and May 1.


What's Up
By Tony Hoffman The Sky for August 2008
Two Eclipses (but none for us). E clip ses oft en com e in pairs, a solar eclipse followed by a lunar two weeks later, or vice-versa. This month sees such a pair. On August 1, the just-risen Sun will be eclipsed in northern Canada. The eclipse track will then cross northern Greenland and the Arctic Ocean, Siberia, Mongolia and northwest China, ending at sunset in central China. Maximum eclipse, 2 minutes 27 seconds, will occur in northern Russia. A deep partial lunar eclipse will be visible August 16 in parts of Europe, Asia and Africa. Perseid Time. T h e gib b ou s M oon will set a r ou n d 1:30 on Tuesday morning, August 12, setting the stage for prime viewing hours of the Perseid meteor shower. Observers in dark-sky locations may see upwards of 60 Perseids, debris from Comet Swift-Tuttle, per hour. From the city, we'll be lucky to see 10 per hour. Outer Worlds Abound. J u p it er will b la ze a t m a gn itude -2.6 in eastern Sagittarius, but one constellation over, another outer world has its heyday. Eighth-mag Neptune is opposite the Sun August 15 in Capricornus. It's visible in binoculars from a reasonably dark sky, and a small telescope will show its bluish disk, 2.4 arcseconds across. Pluto drifts not far from star 6 Sagitarii, while sixth-magnitude Uranus lies 5 degrees from Phi Aquarii. Mars and Saturn are visible after sunset, along with Venus and Mercury, setting the stage for multiple conjunctions between these worlds, the one involving Venus and Saturn August 13 the most dramatic. August's Constellations. H er cu les a n d t h e Su m m er Triangle are nearly overhead in the early evening, while the center of our galaxy (marked by Sagittarius, Scorpius, and Ophiuchus), with its trove of star clusters and nebulae, lies to the south. The Big Dipper swings down, as if to take a scoop out of the northern horizon, while Arcturus dips to the northwest. Out of the east swing fall's constellations: Pegasus, Andromeda, Cassiopeia, Triangulum and Perseus. August 1 New M oon a t 6: 13 a .m .; t ot a l sola r eclip se visible mostly in Asia.
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August 2 M oon lies n ea r Ven u s. August 3 M oon lies n ea r Sa t u r n . August 4 M oon lies n ea r M a r s. August 5 Ven u s p a sses a d egr ee fr om R egu lu s. August 6 Ast er oid P a r t h en op e a t op p osit ion . August 8 F ir st -quarter Moon at 4:20 p.m. August 10 M er cu r y lies n ea r R egu lu s; M oon lies n ea r Antares. August 12 P er seid m et eor sh ower p ea k s. August 13 M oon lies n ea r J u p it er ; Ven u s in close con junction with Saturn. August 15 Nep t u n e a t op p osit ion ; M er cu r y lies n ea r Saturn. August 16 F u ll M oon a t 5: 16 p .m .; p a r t ia l lu n a r eclipse visible from Eastern Hemisphere. August 23 L a st -quarter Moon at 7:50 p.m.; Mercury lies near Venus. August 25 M oon a t p er igee, 229,097 m iles fr om Earth, 11:59 p.m. August 30 New M oon a t 3: 58 p .m .

Mars Overtakes Saturn As Jupiter Enters the Evening Skies
By Joseph A. Fedrick
Mars has been moving swift ly a ga in st t h e b a ck ground stars of the evening sky. This spring and early summer, I watched a ruddy pink Mars that contrasted dramatically with the faint-blue-white diamond-like stars of the beehive cluster (M44) as it passed in front of the star cluster on May 22. By July 2, Mars had already passed blue-white Regulus in Leo. Coral-colored Mars and yellow Saturn formed a dramatic pair, sinking low in the west at 9:30 p. m. on July 10. The pair fit into the same field of view in my widefield objective at 50x in my 60mm refractor that night. Mars appeared as a featureless tiny disk at 50x.The rings of Saturn presented themselves at a narrow angle so that the Cassini division was barely visible in my refractor at 100x and even difficult in my 6-inch Newtonian reflector at 150x during late May and early June. The narrow angle of the rings allowed the viewing of both hemispheres of the disk of Saturn so that the North Equatorial Belt was becoming visible, if just barely, for the first time since the mid-1990s. Jupiter was rising in t h e sou t h ea st a t d u sk b y J u ly

Fedrick continued on page 10


A Message from AAA President Richard Rosenberg
Hello, members: Good news! Members have contributed $3,000 to reach our target of the matching fund set up by Neil Tyson in honor of Fred Hess. Thanks to all who contributed and especially to Neil. Any ideas you have to use this bounty to advance our goal of "promoting the study of astronomy, to emphasize the cultural and inspirational value of the subject" would be appreciated. Summer is here, so check out the stars. Coming up on Friday, August 8 is the Science Cabaret at the New York Aquarium in Coney Island. Some of us will participate by bringing out scopes. If you want to join us, contact me. Each Thursday evening through August 28, a free film will be shown outdoors in Brooklyn Bridge Park in Brooklyn. The series is sponsored by the Sci Fi Channel, which is also contributing four 8" Dobsonian telescopes. Join me before and after the movie to help me show off the skies to a large audience. Don't forget our annual Urban Starfest in the Sheep Meadow of Central Park. From dusk to 10 p. m. on Saturday, September 6, members will show off their scopes and the sky to visitors. Let me know if you 're bringing a scope; free parking nearby will be arranged. If it's rainy or cloudy, we'll try again the following evening. On Friday evenings September 26 and October 3, the Parks Department will host a nature walk and solar observing from 6 to 7:15 followed by stargazing in Wagner Park along the Hudson at the southern end of Battery Park City. Friday, October 3 also begins our 2008-09 lecture series at the American Museum of Natural History. MordecaiMark Mac Low of the AMNH will speak on "The Puzzles of Planet Formation." Lectures begin at 6:15 and end at 8, and are free and open to the public. A few things are going slower than expected, but observing sessions at North-South Lake in the Catskills are imminent, possibly in August, and we continue to enjoy presenting our Recent Advances Seminar at NYU, while trying to make arrangements there for our observers' group and other club activities. Rich Rosenberg, AAA President, pr esident @a a a .or g, (718) 522-5014

Wolf-Rayet Stars Are Fascinating, to Say the Least
By Mary Carlson
With launch of the international G a m m a R a y Large Area Space Telescope (GLAST), the Recent Advances Seminar this month will look at a probable source of gamma-ray bursts, Wolf-Rayet stars. Considered the hottest stars in the cosmos, these rare stars represent the last phase of main-sequence type O red supergiants, which were originally 25-100 times the mass of our Sun. At the Wolf-Rayet stage, they burn with a symphonic intensity and die in a cataclysmic explosion. They fuse heavy metals in their cores, generating intense heat which, in turn, drives fierce stellar winds up to 5 million mph. As the winds blow off the outer layers, the star's mass is greatly reduced, triggering a gravitational collapse and creating a new generation of stars. Originally, Wolf-Rayet stars wer e t h ou gh t t o b e single stars, but with the extended resolving power of the Hubble's planetary camera, scientists are discovering many Wolf-Rayet stars are actually part of binary and possibly multistar systems. These findings are raising more than a few questions: Wolf-Rayet continued on page 9
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Volcanoes Are Part of the Solar System's History and Present
By Mary Carlson
At a recent Recent Advances Seminar, t h e gr ou p discussed the gripping fear an exploding volcano can evoke. Its awesome power terrifies us. Yet, volcanic activity has shaped and reshaped Earth's surface over its 4.5-billion-year history. Basically, a volcano is a rupture in a planet's (or moon's) crust allowing molten rock, ash and gases to escape. It's Earth's way of releasing its continual internal heat caused by both radioactive decay and primordial residue. While our planet has more than 1,000 volcanoes, they're not confined to Earth. The solar system's other terrestrial planets as well as its larger moons have, now or in the past, experienced volcanic eruptions, many far more intense than Mount St. Helens or Kilauea. Our Moon is thought to have been active up to 1 billion years ago. Apollo samples of basaltic rock provide evidence of once-existing lava flows, which have since been obliterated by impacts to the satellite. crater. In addition, Earth-based telescopes have confirmed the presence of methane, a common and somewhat unstable volcanic gas, in the atmosphere. As methane lasts no more than several centuries, the question is raised: How recently has Mars had volcanic eruptions? Jupiter's small moon Io is t h e m ost geologica lly a ctive satellite in the solar system. The reason: tidal friction caused by Io's being continually pushed and pulled by Jupiter and its fellow Galilean moons, resulting in a continuously undulating surface. The internal heat has generated a caldera 125 miles wide, 200-mile long lava flows and sulfuric plumes hundreds of miles high. While the inner planets and Io have molten cores orchestrating volcanic activity, on the outer moons we encounter the phenomenon known as cryovolcanism, which occurs when superchilled water combines with gases such as ammonia or methanol, resulting in explosive eruptions. This, coupled with tidal friction, magnetic fields and yet to be discovered processes, might account for perceived past or present volcanism on Jupiter's other Galilean moons, Europa and Ganymede, Uranus' moon Miranda and Neptune's satellite Triton. In Triton's case, however, the scenario might be of a different origin, that of sunlight penetrating an icy surface and creating gaseous explosions through its crust. The Cassini-Huygens Saturn m ission h a s wid en ed our understanding of Saturn's largest moon, Titan. It's proved that Titan possesses several elements of geochemical activity. The moon's intensely dense atmosphere consists primarily of methane, which appears to be continually replenished. In addition, the Huygens probe detected possible subsurface potassium, an element normally found in the moon's core. Cassini has also detected erupting geysers on Saturn's tiny moon Enceladus. They appear to originate from a series of fissures on the moon's icy surface called "tiger stripes." As Cassini flew through one of these plumes, it detected water vapor along with methane and traces of other volcanic gases. Mary Carlson chairs AAA's Recent Advances Seminar.

Mercury contains one of t h e sola r syst em 's largest craters, Caloris Basin, 140 miles in diameter. The MESSENGER probe will provide more detail during its flyby in October, in later passes and when in orbit in 2011.
Venus has more than 100,000 small-shield volcanoes similar to those on Earth's ocean floor. In spite of the thick sulfuric Venusian atmosphere, these shields rise to as much as 26,000 feet above the surface. Probedetected webs of fractures on the more pancake-shaped volcanic domes have prompted scientists to consider the possibility of current or recent eruptions on Venus. More intensive study might yield startling answers. Mars boasts the most prominent, a n d la r gest , volcanic crater in the solar system. Olympus Mons rises 15 miles above the planet's surface, the largest of a cluster of massive volcanoes. The Martian rovers have been uncovering signs of past activity. While exploring the Columbian Hills for soil samples, Spirit found evidence of pyroxene, magnetite and olivine, all signatures of volcanic activity. The Gusev Crater, Spirit's landing site, harbors much basaltic rock indicative of volcanic events, but none of the characteristics of an impact
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Five Recent Astronomy Books May Interest You
By Dan Harrison
Eyepiece tends to review on e book per issu e, occa sionally two. As you are probably aware, the increased interest in astronomy has led to an increased number of books hitting the shelves in recent years. This article plays some catch-up by briefly discussing five new books of interest. Ian Redpath, one of the best a n d m ost p r olific writers in astronomy, and Wil Tiron, one of astronomy's leading celestial mapmakers and illustrators, have fully revised and expanded "Stars and Planets: The Most Complete Guide to the Stars, Planets, Galaxies, and the Solar System" (Princeton University Press, paper, $19.95), first published in 1984. Highlights include detailed charts covering all 88 constellations in the Northern and Southern hemispheres, data and notes on all bright stars, detailed Moon maps and descriptions of main lunar features, tips on choosing and using binoculars and telescopes (to suit any budget). The book is also billed as the only guide to provide annual planetary data as a downloadable Web resource; maps through 2011 are available at www.collins.co.uk/stars and planets. Another top astronomical writer, Philip S. Harrington, has updated "Star Ware: The Amateur Astronomer's Guide to Choosing, Buying, and Using Telescopes and Accessories (John Wiley & Sons, paper, $21.95), now in its fourth edition. This comprehensive volume presents much on binoculars, not just scopes. It also has a chapter on "A Few Tricks of the Trade," covering such subjects as evaluating sky conditions, your observing site, star parties and astronomy conventions, and all-azimuth GoTo and PushTo mounts. A third book chockablock wit h in for m a t ion is "Illustrated Guide to Astronomical Wonders" by Robert Bruce Thompson and Barbara Fritchman Thompson (Make:Books, paper, $29.99). The book contains 50 chapters on constellations, alphabetically from Andromeda to Vulpecula. Although the book is primarily an observing guide, "several of our advisors pointed out that we needed to at least touch on the fundamentals of observing and equipment," so two chapters were added. The book is stuffed with text, charts, illustrations and photographs. Since almost everything is black and white, material hardly jumps out at the reader, vs. the profusion of color in the illustrations and photos in the RedpathTirion book. If you want to know more a b ou t m et eor s a n d m eteorites, pick up "Field Guide to Meteors and Meteorites" by O. Richard Norton and the late Lawrence A. Chitwood (Springer, paper, $39.95), the latest in Patrick Moore's Practical Astronomy Series. This is a highly detailed volume, perhaps more than you're looking for, but Norton makes a good point: "No longer must amateur astronomers be content with passively observing the heavens. Not only are meteorites fragments of asteroids but some also contain interstellar grains--and we can actually hold them in our hands....A new world of exploration awaits the backyard scientist. Amateur astronomers, in particular, have surveyed the solar system with their telescopes but their surveys remain incomplete. Now it is time to look down as well as up; to set aside your telescopes, and arm yourselves with metal detectors, magnets, magnifiers and microscopes, and prepare to explore the wonders of the solar system locked inside these rocks from space for the last 4.56 billion years." Does astronomical history in t er est you ? I f so, "Keep Watching the Skies! The Story of Operation Moonwatch & the Dawn of the Space Age" by W. Patrick McCray (Princeton University Press, $29.95) might be of interest. After the Soviet Union launched Sputnik in 1957, many citizen-scientists, including amateur astronomers, helped professional astronomers by starting Moonwatch teams to spot satellites. They wanted to boost scientific knowledge, and succeeded. Notes McCray: "...many professional scientists maintained reservations as to whether amateurs could actually contribute anything worthwhile to the [International Geophysical Year]. Amateur scientists, however, exploited opportunities the IGY presented and demonstrated that they could make a meaningful contribution to the world's biggest scientific project. For several months, Moonwatchers' participation proved especially critical to the success of the IGY's satellite program....As the largest and most visible program of amateur science for the IGY, Moonwatch also strengthened the networks of amateur scientists both locally and around the world."
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Keeping the Earth Asteroid-Free Takes Science, Soft Touch
Ex-astronaut Rusty Schweickart wa n t s t o sa ve t h e world from an incoming asteroid--the multimegaton variety blamed for killing the dinosaurs--and he thinks the only sure-fire way to keep them away is by using, of all things, diplomacy. Schweickart was on the Apollo 9 mission that circled the Earth in 1969 testing the lunar lander. Now 72, he's been working on NEOs since 2001, trying to alert the world to the problem. Most of the time, he conducts the campaign sitting at a laptop at home. The Web connects him to a global network of other ex-astronauts, astronomers, government scientists, space buffs and more. Many of them are members of the B612 Foundation, which Schweickart helped found to research the problem. There are still so many gaps in our understanding of asteroids that Schweickart says he's had to pioneer a lot of "asteroidology" himself. The basics of the problem a r e fa m ilia r t o Discover y Channel viewers. Now and then, one of the millions of chunks in the Asteroid Belt gets knocked into a different orbit, one that might one day lead to a collision with Earth. The best place online to follow all this is at neo.jpl.nasa.gov, where Schweickart checks in several times a day. It's a kind of Facebook for asteroids, each one having its own home page, along with a cool Java applet showing its orbits. When it comes to actually dealing with an asteroid, the Hollywood option, of nuking it to smithereens, is the least useful, says Schweickart, largely because you can't control the debris. Serious students of the topic prefer the idea of crashing a spacecraft into the asteroid, thus nudging it into a new orbit. In fact, merely orbiting a spacecraft nearby might do the same trick, on account of the craft's gravitational pull. Because asteroids have t h ese sor t s of ea sily im a gined happy endings, it's a more pleasant apocalypse to contemplate than, say, global warming, for which there is no such easy solution Deadly asteroids have something else going for them: They can be dealt with for a relatively small amount of money. Spending $100 million or $200 million a year for
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a decade will put in place all the have a complete census of all of Earth. Such a tracking program warning time of decades ahead of

telescopes necessary to the NEOs that threaten would likely give us a any possible collision.

The hard part of asteroids, sa ys Sch weick a r t , a n d the part he's spending nearly all his time on, involves finding a way to reach a global agreement on how the planet would respond should an asteroid head our way. This is where the astronaut starts to think like a diplomat. Indeed, he's hoping to have a meeting in the fall with the secretary general of the United Nations. Schweickart knows what you're probably thinking: Eliminating an asteroid is a job for Bruce Willis, not for diplomats. Hence, a short lesson from Schweickart, who has an MIT degree in orbital mechanics. When an object like an asteroid is known to be heading toward Earth, its exact splashdown point can't be calculated with any certainty. Instead, scientists know only that it will fall someplace on a thin line along the Earth's surface. These are the sorts of trajectories that make news when wayward satellites drop back to terra firma. Suppose the impact line for a n a st er oid b egin s over Country A, extends through Country B and ends at Country C. To nudge the asteroid so it misses Earth completely, you first have to push it in one direction or another--in effect, toward either A or C. That means residents of A or C will bear a slightly greater risk if the rescue effort doesn't push the asteroid hard enough. Naturally, citizens of A and C, and their leaders, will be screaming for the asteroid to be pushed in the other country's direction. Schweickart says the only fair way to proceed is to have a decision-making formula drawn up well in advance, unaffected by the heat of a crisis. Another reason to involve the U.N., he says, is to overcome global suspicion that a unilateral American anti-asteroid effort would be a ruse to militarize space. Schweickart says he's concerned about the issue. Many in Washington, he says, seem almost exclusively interested in the nuclear option. Reprinted from The Wall Street Journal and edited for space.


Briefs: Water Found Inside Ancient Moon Samples
Water has been found for t h e fir st t im e in sid e a n cient Moon samples brought back by Apollo astronauts. This may force scientists to rethink the lunar past and future, although uncertainty remains about how much water exists and whether explorers could extract it. The water was found inside volcanic glass beads, which represent solidified magma from the early Moon's interior. The beads formed from droplets of molten lava that spewed from fire fountains reaching deep within the primitive interior. 260 ppm of water is the most certain figure now. Either the Moon held onto water from Earth during its creation, or water gathered from elsewhere within 100 million years as the Moon solidified. Any surface water ice likely formed from comets and other external bodies crashing into the Moon. Our galaxy cranks out a b ou t 10 n ew st a r s p er yea r . Now astronomers have found a galaxy near the beginning of time that generates 4,000 a year. At that rate, the galaxy needs 50 million years to become equivalent to the most massive ever observed. Such growth confounds theory. Galaxies are supposed to slowly bulk up their stars over time by absorbing tiny pieces of galaxies. The galaxy, 12.3 billion light-years away, is the brightest starburst galaxy ever spotted in the distant universe. Other galaxies with such rapid rates of star formation are nearby. The question is whether most of the most massive galaxies formed very early in the universe, or whether this is an exception. Black-hole feeding frenzies a r e fu eled b y ga la ct ic collisions, a new study suggests. Scientists guessed recent interactions with neighboring galaxies might have stirred up gas and dust and propelled them toward giant black holes. Astronomers photographed these objects in radio light, and found most of these galaxies seem to have recently collided with a neighbor. Meanwhile, researchers announced that supermassive black holes feed just like smaller stellar black holes. Scientists observed the huge black hole at the center of the M81 galaxy, and compared results to observations of smaller black holes. Total energy coming out of the massive black hole was larger but the relative amounts of energy being emitted at different wavelengths were roughly the same. Speeds of the jets seem to work the same way. Material falling onto a black hole seems to travel at the same speed, regardless of the black hole's size. A NASA spacecraft's first flyby of M er cu r y h a s yielded much information, some of which confirms volcanism occurred there. Information about such mysteries as Mercury's magnetic field and geological history also has flooded in. The angle of the Sun's light on Mercury yielded evidence pointing to volcanic activity. MESSENGER also confirmed that the surface is very low in iron, though Mercury's high density implies its core is iron-rich. MESSENGER found more faults than Mariner 10, suggesting the strain from Mercury's contraction was at least one-third greater than thought. A good-sized asteroid sa ilin g p a st E a r t h t u r n s ou t to be two giant rocks. The setup was thought to be nearly a half-mile wide after its discovery in January. Now seen as two objects orbiting each other, the pair was closest to Earth July 14, about 1.4 million miles away. Scientists want to learn more about binary asteroids because one day they might find one headed our way. Radar observations from Arecibo July 6-7 showed two objects. They're estimated to be 1,970 feet and 650 feet in diameter. The larger one rotates upon its axis in three hours or less.

Asteroids often come in pairs, wit h t h e ob j ect s spinning around each other. Now scientists say sunlight could be the cause of these binaries. A new study suggests energy from the Sun can spin a single asteroid until it ejects material that becomes a separate satellite.
Recent research has shown E n cela d u s d oesn 't produce enough heat in its present configuration to keep water from freezing down to its core. Scientists calculated tidal heating expected inside Enceladus from the uneven tugging of Saturn. In models, the moon couldn't sustain an ocean for more than 30 million years. This could mean the ocean froze up long ago. Or perhaps more likely, Enceladus generated a greater amount of heat at some point during the past 30 million years by being in a more eccentric orbit than now. If Enceladus' orbital eccentricity has always been what it is today, the moon would have frozen completely solid billions of years ago. But there's likely some kind of ocean, so something must have prevented Enceladus from fully freezing. Astrobiologists probing the suitability of Enceladus to life may have to incorporate a dynamic ocean that has shrunk and expanded over million-year timescales due to the moon's fluctuating eccentricity. 7 Continued on page 8


Briefs: Phoenix Mars Lander Keeps Amassing Data
Continued from page 7 A silicon device wit h t h ou sa n d s of sla t s of t in y m ir rors resembling a jalousie window could boost the efficiency of NASA's next-generation space telescope, the Constellation-X Observatory. The new device uses nano mirrors to diffract X-ray and extreme ultraviolet range beams without energy absorption that typically occurs with X-ray diffraction gratings. Diffraction gratings disperse X-ray wavelengths in much the same way a prism refracts visible light. A lot more Martian rocks wer e a lt er ed b y wa t er than scientists originally thought. New observations by NASA's Mars Reconnaissance Orbiter, circling Mars, reveal that vast regions of the southern highlands were altered by water in a variety of environments billions of years ago. Key to the finding is the discovery that rocks called phyllosilicates are widespread on at least the southern hemisphere. Water present on Mars from 4.6 billion to 3.8 billion years ago transformed some rocks into phyllosilicates. One implication: Some environments that formed the phyllosilicates wouldn't have been antagonistic to potential life, unlike conditions that formed sulfates, which formed in a highly acidic environment. NASA's Phoenix Mars Lander u sed it s r ob ot ic a r m to expose more of the hard icy layer just below the Martian surface so it can more easily gather a sample for analysis. The trench was 8 by 12 inches after digging by the arm. Controllers sent commands to extend the length of the trench by 6 inches. Scientists said tests on Earth suggested more area must be exposed to collect a proper sample. Samples of shallower, non-icy soil have been examined by Phoenix's wet chemistry lab and optical microscope. Earlier, the lander stuck its fork-like probe into nearby dirt to see how well it conducts electricity and heat. Results for the first wet-chemistry test suggested the Martian regolith contained several soluble minerals necessary for life, including potassium, magnesium and chloride. The probe can also be held in the atmosphere to take measurements of water vapor. Liquid water on Mars m a y h a ve on ce d r izzled fr om the sky or collected as dew on the ground. Falling water left signs in the Martian soil measured by NASA's Vi8

king, Pathfinder and rover missions. It was already known that it snows around the north pole, and there's ample evidence that water used to well up from beneath the surface as hot springs or groundwater. But water falling from the Martian sky is something never proven. The new study suggests liquid water still existed in the atmosphere from 3.5 billion to 1.8 billion years ago. There's evidence the soil had lost many of the elements in the original rock fragments which formed the soil. That pattern suggests water once moved downward through the dirt and washed those elements away. Why is Mars two-faced? Scien t ist s sa y fr esh evidence supports the theory that a monster impact punched the planet, leaving behind perhaps the largest gash on any body in the solar system. The southern hemisphere is pockmarked and filled with ancient rugged highlands. By contrast, the northern hemisphere is smoother and covered by low-lying plains. An asteroid or comet whacked Mars some 4 billion years ago, blasting away much of its northern crust and creating a giant hole over 40% of the surface. New calculations reveal the Borealis basin measures 5,300 miles across and 6,600 miles long. Some scientists believe a t lea st on e m et eor it e fou n d in Antarctica preserves evidence of ancient life on Mars. Now, new work reinforces an earlier suggestion that evidence of life on the early Earth might be found in meteorites on the Moon. Some suggest material ejected from Earth during the Late Heavy Bombardment 4 billion years ago, when Earth was subjected to a rain of asteroids and comets, might be found on the Moon. In many cases, pressures could be low enough to permit survival of biological markers, making the lunar surface an extremely good place to look for evidence of early terrestrial life. Voyager 2's journey t owa r d in t er st ella r sp a ce h a s revealed surprising insights into the energy and magnetic forces at the solar system's outer edge, and confirmed the solar system's squashed shape. Voyager 1 and Voyager 2 continue to send data to Earth more than 30 years after they first launched. Each spacecraft has now crossed the edge of the solar system. The reason for the asymmetrical shape rests with an interstellar magnetic field that puts more pressure on the southern region of the solar system.


Events on the Horizon August 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. Observing at Great Kills Gateway National Park, Staten Island, P, T, C Next date: September 20. Thursday, August 14, 6 to 8 p. m. Recent Advances in Astronomy Seminar, M Note earlier time. NYU location to be determined. Check aaa.org for details. Next date: September 11. Wednesday, August 20, 7 p. m. Quarterly AAA board meeting, M, HQ. All members are invited to attend. Friday, August 29, dusk to 10 p. m. Observing at Carl Schurz Park, Manhattan, P, T, C Next date: September 26. Saturday, August 30, 10 a. m. to noon Solar Observing, P, C Conservatory Waters, Central Park. Next date: September 27. Saturday, August 30, 1 to 4 p. m. Observers' Group, M, HQ Next date: September 27. plans, binary asteroids, and updates from the Phoenix Lander and CERN's Hadron Collider. Mary Carlson chairs AAA's Recent Advances Seminar

Tuesday, August 5, dusk to 10 p. m. Observing at Cadman Plaza, Brooklyn, P, T, C Next date: September 2. Wednesday, August 6, 8-11 p. m. Observing at Prospect Park, Brooklyn, P, T, C Next date: September 10. Thursday, August 7, 14, 21, 28, 6 to 10 p. m. Movies with a View, free, P Brooklyn Bridge Park, Brooklyn A free movie plus observing through 8" Dobsonian telescopes. See http://www.brooklynbridgepark.org/go/ news/free-outdoor-film-series-movies-with-a-viewreturns for a list of movies and other details. Friday August 8, 7 to 8:30 p. m. Observing at New York Aquarium, Coney Island, P,T Also, Science Cabaret with science-oriented events. Saturday, August 9 , dusk Wolf-Rayet continued from page 3 Are Wolf-Rayet stars' sizes and distances being assessed accurately? Are they in the 7-20 solar-mass range or are they smaller? What effect does the smaller companion star have on the host? Is mass being transferred from one star to another? Is the companion responsible for altering orbits, rotation rates and mass-loss rates? How specifically does a Wolf-Rayet star unleash the brightest explosive energy in the universe, a gamma -ray burst? GLAST will hopefully provide some answers. As time permits, we'll also cover Cassini's extended two-year mission, NASA's future space-exploration

Contacting the AAA
If you want to join, volu n t eer , p a r t icip a t e in events, have a question or change your address, e-mail members @aaa.org, or leave a message at AAA hq: (212) 535-2922. Also, visit us on the web at www.aaa.org. If you're interested in writing an article for Ey epiece, contact editor Dan Harrison at edi9 tor@aaa.org or (914) 762-0358.


Light Pollution continued from page 1 to be fitted with shields to block unwanted glare. Rosenthal asserted that the city issued memos which disregarded the facts, such as saying that all lights would have to be changed vs. when a light fixture needs to be replaced. "The city doesn't like the state to tell them what to do, but the state has a role to play," she said. The multiple-bill approach is en d or sed b y L eo Smith, northeast director of the International Darksky Association, who calls it a sensible way to get the ball rolling on light-pollution legislation. "It might make sense for individual bills to be focused on individual applications. For example, if the bill covers parking, why not require new parking lots to use instant on/off lights and motion sensors? And a bill on street lighting requiring shielding could be shown to utilities not to adversely affect energy consumption." In Smith's view, the key with legislators is to get the first bill through, then try for others. "They would see the good effects of one bill, so you perform an educational function. Instead of an all-encompassing bill, put your toe into the water, then your ankle and then your knee." Meanwhile, the Suffolk County villa ge of

Patchogue has passed an extensive light-pollution bill which, like a number of failed state bills, mandates fullcutoff exterior fixtures when lighting is at least 1,800 lumens (100 watts incandescent). Lesser lighting levels require fully shielded fixtures. (Both full cutoff and fully shielded prohibit light above the horizontal. The former, but not the latter, also limits intensity of light in the socalled "glare zone" between 80 and 90 degrees vertical.) All streetlight luminaires must be full cutoff, except for historic-style decorative lighting, where some leeway is allowed. In addition, "All residential and nonresidential exterior lighting shall not cause light trespass and shall protect adjacent properties from glare and excessive lighting." The ordinance also states that "Unshielded residential luminaires are allowed, provided lighttrespass limitations are met." Fedrick continued from page 2 10.The planet revealed two equally dark gray-brown equatorial belts at 50x in my refractor along with fainter, less distinct gray belts at higher latitudes. Three Jovian moons were visible. The planet shimmered in poor seeing near the horizon. Jupiter rose earlier each night as Saturn sank in the west. A new season for evening Jovian observing began as this year's season for evening observing of Saturn ended.

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