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Journal of the Amateur Astronomers Association of New York April 2008 Volume 56 Number 4, ISSN 0146-7662

EYEPIECE
tronaut," indicating the difficulties that lie ahead.

Diverse Asimov Panel Discusses Mining Space Resources
By Thomas Haeberle
To discuss "Mining the Sky," this year's Isaac Asimov panel at the AMNH March 13, there was a diverse group of experts in planetary science, aerospace engineering, environmental engineering and space law.
Planets, moons, asteroids and comets contain resources such as water and minerals, valuable to astronauts and potentially to Earth, with other elements such as platinum as a byproduct of the extraction. "With the use of space technology we have the ability to tap these resources," noted John S. Lewis, professor in the Lunar and Planetary Lab at the University of Arizona and a physicist-chemist who's expert in cosmochemistry planetary atmospheres. Lewis termed economic development of material and energy resources of near-Earth space important. "Lunar colonies need oxygen. Mining of ilmenite will be a key ore to extracting oxygen [and] ultra pure iron." Lewis hoped we could defray cost s b y "bringing inexpensive products down to Earth. Ferris metals and water will be keystone products of space, with platinum as a byproduct." We could make travel to Mars cheaper by "bringing just enough fuel [to get there], then use the Martian CO2 atmosphere to go home. One ton of equipment will be able to produce 100 tons of fuel." Dr. Cassie Conley, NASA's acting planetary protection officer, responsible for ensuring that missions to other worlds don't contaminate them with terrestrial microbes, borrowed a phrase from the movie "Men in Black" that she's "protecting the universe from the scum of the Earth." The 1967 International Outer Space Treaty, she observed, requires spacecraft exploring the solar system to be clean enough to prevent contamination. "You can bake a spacecraft for three days but not an as-

Dr. Henry R. Hertzfeld, research professor of space policy and international affairs at George Washington University, an expert on legal and economic issues of space who co-authored "Space Economics" and numerous articles, said "Certain freedoms [will test] the use of space: Should all countries benefit, or can there be [national] claims to celestial objects?" Will there be "freedom to mine, will it be like the `law of the sea'" or the lawlessness of the Wild West? He conceded space is expensive and that both government and private investment will be needed. Engineer Curtis Manning wor k s in t h e M a r sh a ll Space Flight Center's Rapid Prototyping Laboratory. Its machines can build various pieces of hardware using metallic dust, such as titanium powder. "Building it layer by layer, you can build a complex piece of equipment. Instead of starting at a drawing board, we start with a computer-aided design (CAD). We program computers and machines with a CAD drawing, and the machine builds solid, three-dimensional objects with incredible detail." Manning is an expert in converting space materials into usable hardware. Asimov Panel continued on page 6

Edward Oravec, Robert Little to Get AAA's Amateur Astronomers Medal
Two of the AAA's most distinguished members, Edward Oravec and Robert Little, will receive the rarely awarded Amateur Astronomers Medal at next month's annual meeting. The medal was last awarded to Tony Hoffman five years ago. For details, see the president's letter on page 3.


What's Up
By Tony Hoffman The Sky for April 2008
How Thin a Crescent Moon Can You See? T h e Moon is new (in conjunction with the Sun) just before midnight April 5. This presents an exceptional opportunity the following evening to try to view an extremely thin crescent Moon barely 18 hours old. It helps that the ecliptic rises at a steep angle as the northern zodiacal constellations sink into the west, so at sunset the Moon will be directly above the Sun (though still invisible in its glare). Still, you'll need an unobstructed horizon to have any shot of seeing it. Sunset in New York is at 7:26. The Moon will set barely an hour after that. Between those times, it becomes a race between the darkening sky revealing the Moon's faint light, and the Moon's decreasing altitude making it less visible. You may not be able to see it at all against the bright twilight, but then again, you might get lucky. Moon Skirts the Pleiades. Aft er su n set Ap r il 8, the Moon traverses the northern part of the Pleiades, the star cluster in Taurus also known as the Seven Sisters. As the Moon slowly moves, it will cover and uncover various stars. Such occultations are best when the Moon's a crescent (as it is here), or else its glare can swamp out the comparatively much dimmer stars (though you'll still need binoculars or telescope to see

On the evening of April 8, the Moon will lie at the northern edge of the Pleiades star cluster.
this event well). April 5 New Moon at 11:55 p.m. April 6 Look for a very thin crescent Moon after sunset (see above). April 7 Moon at perigee, 224,365 miles from Earth, 3:30 p.m. April 8 Moon passes through Pleiades star cluster (see above). April 12 Moon lies near Mars; first-quarter Moon at 2:32 p.m. April 15 Moon lies near Regulus and Saturn. April 20 Full Moon at 6:25 a.m. April 22 Lyrid meteor shower at maximum. April 23 Moon lies near Antares.

February 20 Total Lunar Eclipse Was a Bright One
By Joseph A. Fedrick
The evening of February 20 began mostly cloudy. However, the cloud layer began to break up as the Moon entered the penumbral shadow of the Earth. Fully one minute before the umbral phase of the eclipse was to begin at 9:42 p. m., the lower left edge of the Moon became very dark. The edge of the umbral shadow was very blurred and indistinct so I couldn't time the entry of the Moon into the umbra well. Totality began at 10. The cloud layer continued to break up as the eclipse progressed so that by mid-eclipse at 10:30, the sky became fully clear and transparent. The
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shadow of the Earth on the Moon was a bright golden yellow at its edges and a darker orange-brown at its central areas on the north of the Moon. All lunar maria were clearly visible in my 10x 50 binoculars, as were several lunar craters with bright ray systems, especially Tycho. The umbral shadow of the Moon seemed brighter and more colorful than in two previous eclipses in 2007. However, the Moon at mid-eclipse was higher up in a clearer sky than in those eclipses. That may have contributed to the apparent relative brightness of this eclipse. The sky at mid-eclipse was dark and transparent enough Fedrick continued on page 12


A Message from AAA President Richard Rosenberg
Hello, members: At next month's annual meeting, the AAA will honor two of our most distinguished members, Edward Oravec and Robert Little, with the rarely awarded Amateur Astronomers Medal. In addition, Marion McMorris, who will mark her 70th anniversary as a member next year, will be honored with a certificate for her many productive years with the club. Eddie Oravec joined the AAA at the age of 19 in 1943. Two years earlier he had begun a variable -star observing program. He marks his 65th anniversary as an AAA member this year. During his distinguished activity as an amateur astronomer, Eddie was one of the founders of AAA's Observers Group and chaired it in the late 1950s and early 1960s. He's a past president of the American Association of Variable Star Observers and a recipient of its merit award. He also received an award from the Astronomical League for observational astronomy. Eddie has made 172,000 observations of variable stars. Bob Little is a pioneer in astrophotography. With the late Fred Hess, he took cruises to test the proposition that celestial objects could be photographed at sea. Their conclusion that it could be done ushered in the now -widespread phenomenon of astronomy cruises. Bob has taught courses on astrophotography at the American Museum of Natural History and on telescopes for the AAA. He wrote a leading book in astrophotography, "Astrophotography: A Step-byStep Approach." On a personal note, it was through Bob's observing sessions at Cadman Plaza I had the pleasure of discovering the club. Marion McMorris has been a member of the AAA since 1939. She and her late husband, Leroy, were active in the club for many years, and Marion, now living in North Carolina, continues to enjoy Ey epiece. Many of you may be unaware of the history of our club. If you have Internet access, read the article by Patrick Rizzo on the club's first 40 years. You can find it on our recently renovated website, www.aaa.org. Go to Articles. We've quite a heritage to live up to. Rich Rosenberg, AAA President, pr esident @a a a .or g, (718) 522-5014

April 11 AAA Lecturer Will Discuss LIGO's Public Outreach
Dr. Eric Myers, a scientist wit h t h e L a ser I n t er ferometer Gravitational-wave Observatory (LIGO), will address the AAA Friday, April 11 on "Einstein@Home: Searching for Ripples in Space-Time with your Home Computer." The free public lecture is at 6:15 p. m. at the Kaufmann Theater of the AMNH. LIGO consists of gravitational-wave detectors at sites near Hanford, Wash., and Livingston, La. The passage of a gravitational wave through these detectors will change the lengths of the multi-kilometer-long arms of the interferometers by a mere fraction of the width of a proton. Detecting a distinguishable signal from all the background noise poses a number of challenges. "I will describe some of the properties of gravitational waves, and the different kinds of signals LIGO hopes to detect," Myers says. "I will focus on difficulties associated with extracting a signal from a `continuouswave' source, as might be expected from a rotating neutron star or something similar. The computational requirements for a blind search for such sources in any part of the sky are so taxing that LIGO has enlisted the help of thousands of volunteers around the world, who donate computer time to the Einstein@Home project. I will explain how it works, and how people can join this effort." The project website is at http://Einstein.phys.umw.edu. Myers earned his Ph.D. in t h eor et ica l p a r t icle Lecture continued on page 10
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Truth and Misconceptions about Albert Einstein
By Terrell Kent Holmes
There was a peculiar irony at work involving the scheduling of speakers for the March 7 AAA lecture at the AMNH: Astronomy got in the way. The originally scheduled speaker, Arlin Crotts of Columbia, had to cancel because he had to meet a proposal deadline for the Hubble Space Telescope. His replacement, colleague Eric Gotthelf, also had to cancel because of a sudden imperative involving data gathering on a new pulsar. stand and experience the universe as a single whole." It was that view of God and the universe which led Einstein to theoretical physics, and eventual publication of the Special Theory of Relativity in 1905, where he examined the ideas of space and time. This work revolutionized physics. Other scientists were hot on the trail of this theory but Einstein reached the summit first.

"It's on occasions like [this] that one leans on old friends," quipped lecture chair David Kraft. He asked Lawrence Gould, professor of physics at the University of Hartford, to step in as a second pinch-hitter. Gould's been in residence at CalTech recently, working on the papers of Albert Einstein, which no doubt inspired his lecture on "Einstein: Myth and Magic."
With tongue planted firmly in cheek, Gould showed a photo of the future genius at age 14 to dispel the myth that, since the most famous photographs of Einstein capture him at advanced ages, he was never young. A related misconception, that Einstein was a bad student, has made inroads into popular culture. There's an ad currently gracing the sides of phone booths with a photo of Einstein above the caption "As a student, he was no Einstein." Gould showed a slide of Einstein's report card as a 17-year-old student: His grades placed him near the top of his class. The problem in perception might have been because Einstein sometimes clashed with his teachers, perhaps in rebellion against the authoritarian environment, perhaps because he knew more than they did. "The next time someone tells you that Einstein really was a bad student [and] it's only later that he became brilliant, it's not true," Gould said. Did Einstein believe in God? "For those who believe in God there's good news and there's bad news. The good news is that Einstein did believe in God. The bad news is [that] it's probably not the one that you believe in." Einstein's conception of God was pantheistic, God as in nature. "The feeling he got, this cosmic religious feeling, which [knew] no dogma and no God conceived in man's image, [came] from a deep conviction of the rationality of the universe and a yearning to under4

Gould also discussed the larger implications of the General Theory of Relativity, such as the gravitational bending of light, the nature of black holes and the expansion of the universe. There's a wonderful symmetry in the fact that this paper, famous for the equation E=mc2, was only three pages long. Just as the theory stated that small masses can produce astonishing amounts of energy, this brief paper would herald a seismic change in scientific and world history.
After recommending several books by and about Einstein, including studies on the General and Special Theories of Relativity, Gould concluded with a simple "So there," after which he posted the wonderful photo of Einstein sticking out his tongue. Before everyone left the auditorium, Kraft noted there'd been some question whether Einstein had actually spoken to the AAA. Kraft suggested that, since Gould played a 1946 audio clip of Einstein discussing the Special Theory of Relativity, it could be said without a doubt that the great man indeed addressed the Amateur Astronomers Association of New York.

AMNH Saturn Exhibit
"Saturn: Images fr om t h e C a ssin i-Huygens Mission" opens April 26 in the IMAX Corridor on the first floor of the American Museum of Natural History and runs through March 29, 2009. The exhibition will have more than 30 up-close views of Saturn, ranging from small individual to large composite images, sent by Cassini. Pictures from the Huygens probe that landed on Titan, Saturn's largest moon, will be displayed alongside images of the giant geyser discovered on Enceladus.


Ideas Are Offered on Tagging, Deflecting Asteroids
How do you tag and track an asteroid that might be on a collision course with Earth? Winners of The Planetary Society's $50,000 Apophis Mission Design Competition had innovative solutions. Entrants designed a mission to rendezvous with and "tag" a potentially dangerous near-Earth asteroid. Tagging would allow scientists to track an asteroid to determine whether it will impact Earth and if so, gauging whether to mount a deflection mission. NASA and the ESA co-sponsored the competition. The NEO Apophis was the competition's target because it will come closer to Earth in 2029 than geostationary satellites. If it passes through a small "keyhole" as it travels by Earth, its trajectory could be diverted so it will impact Earth in 2036. Estimates term the probability of an impact very low. First place went to SpaceWorks Engineering of Atlanta and SpaceDev, Poway, Calif., for their mission Foresight. Foresight proposes a simple orbiter with only two instruments and a radio beacon at a cost of $137.2 million. The spacecraft would leave Earth between 2012 and 2014, arriving at Apophis 5-10 months later. It would observe and track the asteroid. Foresight would orbit Apophis to gather data with a multi-spectral imager for one month. It would then leave orbit and fly with Apophis around the Sun at a range of 1.2 miles. The spacecraft would use laser ranging to the asteroid and radio tracking from Earth for 10 months to determine the asteroid's orbit and how it might change.

The Georgia Institute of Technology, Atlanta, took first place in the student category for a mission design entitled Pharos.
Pharos would be an orbiter with four science instruments (multi-spectral imager, near-infrared spectrometer, laser rangefinder and magnetometer) that would rendezvous with and track Apophis. It would also carry four instrumented probes it would launch over two weeks. The probes' accelerometers and temperature sensors would measure seismic effects of probe impacts, to explore Apophis' interior structure and dynamics.

Volunteers Sought for Cosmology Research Project
A new distributed computing project, Cosmology@Home, will allow people around the world to participate in cosmology research by sharing their unused computing cycles. "When you run Cosmology@Home on your computer, it uses part of the computer's processing power, disk space and network bandwidth," says project leader Benjamin D. Wandelt of the University of Illinois. "Our goal is to search for cosmological models that describe our universe." Participating computers will calculate predictions of observable properties of the universe made by millions of theoretical models with different parameters. Each work package will simulate a universe with a particular geometry, particle content and "physics of the beginning." Predictions will be compared with such data as fluctuations in the cosmic microwave background, largescale distributions of galaxies and galaxy clusters, and the universe's acceleration. Cosmology@Home could help design future cosmological observations and prepare for analysis of future data sets, such as those to be collected by the Planck spacecraft, Wandelt says. The research group is involved in several areas of theoretical and phenomenological cosmology: the earliest instants of time when the universe formed, the cosmic microwave background, the cosmic dark ages, structure formation, dark matter and dark energy, and the development and adaptation of mathematics, statistics and computation to advance cosmology. "We plan to offer several kinds of computations to participate in. All will contribute to research projects in cosmology by the physics and astronomy departments of the university," Wandelt says. Info: www.cosmologyathome.org.

Old Magazines Available--An AAA member is
relinquishing a large number of back issues of S k y & Telescope. If you're interested, contact president@aaa.org.
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Two Bad Gases Caused All but One of Earth's Extinctions
If you think of a mass extinction on E a r t h , you probably think of the asteroid that hit what's now the Yucatan 65 million years ago, killing the dinosaurs and some 70% of other species. But according to Peter D. Ward, professor of biology, and Earth and space sciences at the University of Washington, 27 years of research proves the famed asteroid hit was the only time a mass extinction was caused by a space-object impact. are daunting. "One thousand parts per million is a time where we have never had an ice cap," Ward said. There were huge spikes eons ago. More recently, "In 1860 there were 290 ppm. In 1940, over 300. From 1960 to 2000, from 310 to 380. It's accelerating at 2 ppm per year, so it will be 200 years until we hit the nasty thousand mark the rate things are going. Some think it's going faster and could hit 1,000 in 120 years. If so, we get to a world where sea level is up 8 feet. If Greenland ice and Antarctica melt, it will be up 240 feet."

The villain in more than 10 m a j or a n d m in or mass extinctions is hydrogen sulfide. All others, Ward recently told a Hayden audience, show the hallmark of the deadly compound as well as lethal levels of carbon dioxide. During a number of short-term catastrophes caused by volcanic and other phenomena, Ward said, ocean circulation ceased and the seas lost their dissolved oxygen, producing uniform mass heat on Earth and culminated by a microbial takeover by hydrogen sulfideproducing microbes. He was clear that this could happen again. As for carbon dioxide, the numbers past and present
Asimov Panel continued from page 1 He believes it's just a matter of time before rapid prototyping will be cost-effective enough to be performed in space. "We could devise a process that would use raw materials in space to create whatever an astronaut might need. It would mean less hardware to transport to space." Murray W. Hitzman, professor of economic geology at the Colorado School of Mines, is expert in depositand district-scale mapping of mineral deposit formation. He said it already costs billions for mining operations on Earth, so space mining may be comparable in price. Conley expressed concern a b ou t wa st e m a n a gement when in space or on the Moon. Manning felt his rapid prototyping machine would be useful for that, as well for repair on the human body. "Titanium is healthy for the human body to do repairs on hips," for example.
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Circulation systems k eep ocea n s oxygen a t ed . Heat differentials between the poles and the tropics produce ocean currents and winds. Without these, Ward said, Earth would be a much different place.
"At one point in the past, the microbial content of oceans changed, from one of microbes that used oxygen to one where all microbes lived in water devoid of oxygen and could only live that way." Hydrogen sulfide, he noted, isn't simply a phenomenon from volcanic eruptions. Even today, there are many vents that emit the gas, so a new hydrogen sulfide asked about helium 3 and its potential to power Earth for centuries through nuclear fusion. Lewis said "Mining of helium 3 on the Moon would be a delicate operation and may be years away." Hitzman felt "living on the Moon may bring into play space law or lawlessness." No panelist took a d efin it ive st a n d on m in in g the skies. Lewis felt it would be most economical to mine asteroids in space or near-Earth space, to extract metals such as an iron, and water, and get valuable byproducts. Hitzman referred to "sexy" expensive byproducts such as gold, diamonds and platinum. "Mining the sky for energy [and resources] may happen sooner than we think." Lewis argued his proposals are technologically and economically feasible if done by private enterprise, not government. "The resources available in the asteroid belt are truly staggering. Ten billion people will be supported by near-Earth objects in which one-third will [or would have] hit the Earth. We would all benefit by doing the mining and processing out there on other planets and

Moderator/Hayden director Neil deGrasse Tyson


Review: A Profile of Amateurs and their Clubs--Sort Of
By Dan Harrison
Do you know what percentage of a m a t eu r astronomy-club membership is women? According to a book published late last year, "Currently women represent approximately 15%." There's a problem with that statement, especially the word "currently." The statistic comes from 2002 data. So when the book was written, the data were five years old. How tangible are these needs today? Have some gone up or declined? Beats me. To be fair, the book has some current information. It mentions that beginning in 2007, a National Science Foundation-funded study conducted in part by the ASP will examine the educational value of education-andpublic-outreach activities of amateur-astronomy clubs.

Such outdated data run through "Science Education Under the Stars: Amateur Astronomers Engaged in Education and Public Outreach," published by the Astronomical Society of the Pacific (paperback, $10). Here are a few more examples:
"A 2002 ASP survey on a m a t eu r a st r on om er s and their outreach activities...found that about half of those amateur astronomers who were not engaged in outreach stated that they...lacked the time for it. Besides that, the survey found that 46% of those interested in outreach felt they lacked the necessary expertise or specialized knowledge needed to conduct education and public outreach." This is a rather meaningless statistic. The Internet, to state the most obvious example, has become pervasive since 2002, if it wasn't already. Why wasn't a more recent survey conducted to reflect that and other trends? "The vast majority (83%) of amateur astronomers who responded were male and more than half were between 31 and 50....Another 30% were 51 to 65." Again, 2002 was five years before publication of the book. Why couldn't the ASP, with all its resources, have come up with a more recent profile? "Amateurs stated in the 2002 su r vey t h a t a va r iety of support may aid them in conducting more or better outreach including ready-made presentation materials, access to equipment, training in understanding audiences, better access to experts, training in presentation skills, networking, training in content areas, and a mentoring structure..."

That the ASP is ca p a b le of u p d a t ed r esea r ch is also evidenced by a 2007 survey, discussed in the book, of women in astronomy clubs. Almost two-thirds (65%) feel their club meets or exceeds their goals and needs. Only 6% were truly disappointed in their club, while 28% offered a qualified endorsement of their club's ability to meet their needs.
"When asked how astronomy clubs might better serve women, {many} suggested that clubs should not focus on simply encouraging females to join, but rather to increase the diversity of the clubs by thinking about age, race and ethnicity as well. It was suggested that both current club demographics, and the fact that astronomy can be an expensive hobby if one considers the technology involves, were barriers that need to be overcome." Many women are less comfortable a t d a r k -sky star parties due to their often remote and dark locations, and the lack of amenities. A number of respondents suggested women could be better served by development of special-interest groups or special-interest events, with a focus on young women, introductory-level skills or both. Hopefully, future ASP studies will be based on

Cosmological Concert
"Symphony in Space" is the theme of a family concert Saturday, April 26 at Carnegie Hall at 2 p. m. The Orchestra of St. Luke's will perform the introduction to "Also Sprach Zarathustra" by Strauss, "Jupiter" and "Mars" from Holst's "The Planets" and the finale from Mozart's "Jupiter" Symphony No. 41, among other works. NASA images will backdrop the concert. Preconcert activities begin at 12:30. Tickets are $9.
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Briefs: Mars' and Venus' Atmospheres Quite Similar
Two nearly identical spacecraft fou n d M a r s' and Venus' atmospheres to be surprisingly similar. The ESA's Mars Express and Venus Express are in orbit around the planets, taking measurements of their atmospheres as they interact with solar radiation. Data show charged particles from gas layers around both planets are being scavenged by solar wind and storms. Although Venus' atmosphere is very thick, dry and hot, and Mars' is very thin and cold, the same processes are happening on both planets. Because neither planet has a protective magnetic field, solar wind can interact directly with their atmospheres. Solar radiation energizes atmospheric particles so they accelerate and escape from the planets. Newfound glowing spots on J u p it er seem u n expectedly to come from electron beams whipping around its volcanic moon Io. Io causes glowing spots hundreds of miles across on Jupiter similar to the aurora borealis. As Jupiter spins, its magnetic field sweeps past Io, stripping off roughly 1 ton of matter every second. This matter becomes electrically charged plasma in the magnetic field, forming a doughnut-shaped cloud. As Io orbits the planet, plasma surges around it, creating waves that blast Jupiter's atmosphere with electrons to create auroras. NASA scientists have created a n ew m a p of t h e south lunar pole with Earth-based telescopes 50 times more detailed than the last version in 1994. The map shows craters four times deeper than the Grand Canyon and hundreds of miles wide. The map will be used to scout for robot or human landing sites, and to investigate lunar mysteries. Many craters imaged have never seen direct sunlight because of their depth and location. Such areas are prime spots to search for water ice or hydrogen deposits that would normally evaporate from solar heating. To create the map, scientists bounced microwave beams off the craggy bottom of the Moon. Sir Arthur C. Clarke, on e of t h e m ost r en own ed and popular science-fiction writers of the 20th century, died at 90. Clarke's vision of the future, and its technology, popularized in films like "2001: A Space Odyssey," captured the popular imagination. He wrote vivid--and detailed-- descriptions of space shuttles, super computers and rapid communications systems. His writings gave science fiction a human and practical face. Clarke, a scientist who wrote dozens of books, inspired "Star Trek."
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During World War II, Clarke predicted that, at 22,000 miles above the Earth, communications satellites in geostationary orbit would allow electronic signals to be bounced off them around the globe. Scientists have discovered con cen t r a t ion s of a m ino acids in two meteorites more than 10 times higher than levels measured in similar meteorites. The finding strengthens the belief the early solar system was far richer in the organic building blocks of life than thought. Researchers took small samples from three rare CR chondrites, which date from the solar system's formation. The rocks likely came from an asteroid long ago shattered. These precursors of life were probably present in other primitive bodies, such as comets, that also rained material onto the early Earth. Five spacecraft that flew p a st E a r t h h a ve d isplayed unexpected anomalies in their motions. Scientists have discovered five spacecraft raced either a tiny bit faster or slower than expected when they flew past Earth en route to other parts of the solar system. Researchers looked at Galileo I and II to Jupiter, the NEAR mission to the asteroid Eros, the Rosetta probe to a comet, Cassini to Saturn and the MESSENGER craft to Mercury. They didn't confirm a noticeable anomaly with MESSENGER. A beautiful pinwheel in sp a ce m igh t on e d a y blast Earth with death rays. The blazing spiral has the potential to burn worlds from thousands of light-years away. The pinwheel has at its heart a pair of hot, luminous stars locked in orbit with each other. As they circle one another, plumes of streaming gas driven from their surfaces collide in the intervening space, eventually becoming entangled and twisted into a whirling spiral by the stars' orbits. Both massive stars will one day explode as supernovae. The pinwheel is 8,000 light-years away. Earth may have a twin or b it in g on e of ou r n ea r est stellar neighbors. Computer simulations of planet formation show terrestrial planets likely formed around a star in the Alpha Centauri star system. The model showed planets forming around Alpha Centauri B in its habitable zone. It also showed that if such planets exist, Continued on page 9


Briefs: Black-Hole Properties Can be Recreated on Tabletop
Continued from page 8 we should be able to see them with a dedicated telescope. Venus is made of t h e sa m e m a t er ia l a s E a r t h , b u t is bone-dry, hot enough to melt lead, has a chokingly thick atmosphere and even spins backwards. Now some believe the planet's formation may explain all. Two huge, protoplanetary bodies collided head-on and merged to form Venus, but obliterated nearly all water. Perhaps the relatively low amount of an argon isotope detected in Venus' atmosphere, about 400 times scarcer than on Earth, indicates water never really seeped out of the parched, volcano-covered planet. Recent photos of Mercury h a ve r evea led t wo n ew categories of crater. When MESSENGER flew by in January, it photographed several craters with strange dark halos and one crater with a spectacularly shiny bottom. Two craters are in Mercury's giant Caloris Basin. Both have dark rims or "halos," with one partially filled with an unknown shiny material. There could be a layer of dark material under the surface of Caloris Basin, resulting in chocolate-colored rims around the craters. Or, thermal energy from the impacts melted some of Mercury's rocky surface. The mysterious properties of b la ck h oles ca n b e recreated on a tabletop. Scientists created an artificial event horizon using fiber optics. They fired a stream of intense, brief laser pulses inside an optical fiber. The pulses acted like a current of flowing light. Such intense, brief pulses make physical effects visible that would also occur for much longer and weaker pulses, but are hard to detect. Researchers also fired a continuous beam of infrared light down the optical fiber. This created waves that got overtaken by the laser flow, resembling how light waves are overcome by gravitational pull just past an event horizon. The Wilkinson Microwave An isot r op y P r ob e h a s found that neutrinos made up a much larger part of the early universe than they do today. Microwave light seen by WMAP from when the universe was only 380,000 years old shows neutrinos made up 10% of the universe, atoms 12%, dark matter 63% and photons 15%. Dark energy was negligible. Estimates show the current universe consists of 4.6% atoms, 23% dark matter and 72% dark energy. Neutrinos make up less than 1%. For the first time, a st r on om er s h a ve p in p oin t ed the spot where intense winds of two massive stars in a binary system violently collide and have detected the production of high-energy X-rays. The Eta Carinae binary is 100-150 times the Sun's mass and glows brighter than 4 million suns. Astronomers long suspected the pair should emit high-energy X-rays, but until now, didn't have instruments to detect the radiation. The intense Xrays are generated by the collision of the stars' stellar winds, flows of charged gas ejected from their upper atmospheres. A lake that might once h a ve b een h a b it a b le p ossibly filled a crater for a long time on early Mars, new spacecraft images reveal. NASA's Mars Reconnaissance Orbiter captured images that suggest the debris-strewn Holden Crater once held a calm body of water that could have harbored life. A mix of broken boulders and smaller particles called megabreccia contain minerals that formed in the presence of water and mark potentially habitable environments. The first long watery period at Holden Crater probably lasted thousands of years, while the second lake that formed after the crater rim was breached may have lasted just hundreds of years. A NASA spacecraft h a s t a k en t h e fir st -ever image of an avalanche near Mars' North Pole. The High Resolution Imaging Experiment on the Mars Reconnaissance Orbiter imaged tan clouds billowing away from the foot of a towering slope, where ice and dust have just cascaded down. The full image reveals features as small as a desk in terrain 3.7 miles wide and more than 10 times that long. Reddish layers rich in water ice make up the face of a steep slope more than 2,300 feet tall, running the length of the image. In a blow to hopes for fin d in g wa t er a n d life on Mars, scientists think bright streaks detected inside Martian gullies after 1999 were not spurts of water but avalanches of dust. They believe pure liquid water is unlikely to have made such formations in the Centauri Montes Continued on page 10
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Briefs: One of Saturn's Moons Could Have Rings
Continued from page 9 region. The conclusion stems from work with 3-D maps created with HiRISE image data. This is the first time anyone has applied numerical computer models to bright deposits in gullies on Mars. NASA may have t o exp lor e d eep sp a ce wit h ou t the aid of long-lasting nuclear batteries to send spacecraft where sunlight is in short supply. The U.S. inventory of plutonium is running out quickly. The Department of Energy has shelved plans to resume domestic production. Saturn's moon Rhea cou ld b e t h e fir st m oon known to have rings. Scientists detected hints of the rings when Cassini flew by Rhea in November 2005. Instruments measured an absence of electrons around the moon where they were expected and indicated possible debris around Rhea. Since Rhea lies within Saturn's magnetosphere, which traps ions and electrons, scientists expected the moon to be awash with them. Rings could explain the disappearing electrons because the material making up the rings would absorb electrons. Rocky planets like Earth cou ld b e fou n d a r ou n d most Sun-like stars in our galaxy. The finding is based on analysis of dust around 309 stars with masses like our Sun. Spitzer detected heat that radiated from the dust. There was "warm" dust, between minus 280 and 80 degrees, orbiting stars at an estimated distance in the same range that Earth and Jupiter are found. This let scientists infer the presence of colliding larger rocky bodies and estimate that 20%-60% of stars like our Sun in the disk of our galaxy could give rise to rocky planets like Earth. The warm dust trails were found in stars 3 million-300 million years old. Scientists recently made a b r ea k t h r ou gh ob ser vation on Mars' climate: a substantial amount of shortlived water ice in the polar regions. Early models of the seasonal caps of Mars suggested the polar caps would be pure carbon dioxide (CO2), and we now know that Mars' seasonal polar caps are 99% CO2 ice. Later thinking on the subject predicted enough water existed in the atmosphere to form a band of water ice around the polar caps as they receded during spring. This was subsequently
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confirmed in the northern hemisphere, but water ice in the southern hemisphere remained hard to find until now. If there was life in su r fa ce wa t er on M a r s ea r ly on, it might have enjoyed a buoyant, salty ride, if it could thrive in a hostile environment at all, new research suggests. Minerals in sedimentary rocks found at Meridiani Planum by NASA's Opportunity rover suggest they formed in water saltier than Earth's oceans. Water was present at least for short periods at Meridiani Planum, but no one has known how habitable it might have been or whether it was around long enough for life to take hold and endure. Water at this location was rare and transient. Scientists are more optimistic that life might have had a chance on Mars in its early history vs. later on. New observations reveal clou d s of d r y ice t h ick enough to cast significant shadows on Mars. Research finds carbon dioxide, the main component of Martian air, freezes into clouds so dense they dim the Sun by 40%. Lecture continued from page 3

physics from Yale. He's held postdoc positions at Brookhaven National Laboratory, Dalhousie University, Boston University and the University of Texas. Myers has taught at Yale, St. Louis University, the University of Michigan and Vassar.
His research has involved applying computational and non-computational methods to investigate quantum chromodynamics, quantum gravity and modeling collisions of cosmic strings. Myers was part of the team wh ich d evelop ed a n d deployed Einstein@Home in 2004-05. For two years he's been working for LIGO on "Interactions in Understanding the Universe," which will make grid computing resources and LIGO environmental data available to high -school students and teachers to support inquiry-based science education. This spring he's visiting assistant professor of physics at Bard College. The 2007-08 AAA lecture series ends May 2 with David Helfand, astronomy professor at Columbia, on "Global Warming: What We Know and What We Don't Know."


Events on the Horizon April 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 Note: The Recent headquarters April tion as previously observing sessions, Advances seminar will be held at 10, not at a possible alternate locadiscussed. For directions to AAA see aaa.org. sky from dusk to midnight. Suggested donations. Info: custerdonna@yahoo.com.

Tuesday, April 8, dusk to 10 p. m. Observing at Cadman Plaza, Brooklyn, P, T, C Next date: May 6. Wednesday, April 9, 8 to 10 p. m. Observing at Prospect Park, Brooklyn, P. T, C Next date: May 7. Thursday, April 10, 6:30 p. m. AAA Recent Advances in Astronomy Seminar, M,HQ Next date: May 8. Friday, April 11, 6:15 p. m. AAA lecture, P Eric Myers of the Laser Interferometer Gravitationalwave Hanford Observatory will speak on Einstein@Home: Searching for Ripples in Space-Time with your Home Computer. Kaufmann Theater of the AMNH. Friday, April 11, 8 to 10 p. m. Observing at Floyd Bennett Field, Brooklyn, P, T, C Model airplane flying field. Next date: May 9. Saturday, April 12, dusk Stargazing, Great Kills, Staten Island P, T, C Next date: May 10. Saturday, April 12, noon to dusk Custer Institute, Southold, NY Annual Family Astronomy Day Astronomy and space-related events and crafts for all ages rain or shine. Planetarium and dome-theater performances. Solar observing and guided tours of the night

Monday, April 14, 7:30 p. m. Hayden Planetarium lecture, P, AMNH "MESSENGER." As principal investigator for the Mercury Surface, Space Environment, Geochemistry and Ranging (MESSENGER) mission, Sean Solomon heads a multi-institutional consortium of scientists and engineers. He balances this with his position as director of the department of terrestrial magnetism at the Carnegie Institution of Washington.
Friday, April 25, dusk to 10 Observing at Carl Schurz Park, Manhattan. Next date: May 30. Saturday, April 26, 1 to 4 p. m. Observers Group, M, H Next date: May 31. Saturday, April 26, 10 a. m. to noon Central Park solar observing, P, C At the Conservatory Waters. Next date: May 31. Saturday and Sunday, April 26 and 27 Northeast Astronomy Forum and Telescope Show, P Rockland Community College, Suffern, N. Y. 8:30 to 6 Saturday, 10 to 6 Sunday, sponsored by Rockland Astronomy Club. The 17th annual event includes vendors, exhibits, workshops, classes for beginners, planetarium shows, kids events, mirror-grinding demonstration, solar star party and more. A highlight this year will be special programs on women in astronomy and the International Year of Astronomy 2009. $20 adults, $30 two days, kids under 16 free with parent. On Thursday and Friday, April 24 and 25, an astro-imaging conference will precede the forum. Info: at www.rocklandastronomy.com/ neaf.

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AAA Annual Meeting May 21
In accordance with the AAA bylaws, t h e 2008 a n n u a l m eet in g will b e h eld on W ed n esd a y, M a y 21 a t AAA headquarters, 1010 Park Avenue, between 84th and 85th streets. 6:30 p. m.: social gathering. 7:30 p. m.: annual meeting, for all AAA members. The 7:30 p. m. meeting will include elections to fill vacancies on the AAA board of directors. Nominations, besides those made by the nominating committee, may be presented to the AAA president or to the recording secretary no later than seven days before the annual meeting. Each such additional nomination requires the signatures of at least 18 AAA members.

Fedrick continued from page 2 to enable me to see open star clusters M36, 37 and 38 in Auriga and M35 in Gemini with binoculars. The clusters appeared as small, fussy, slightly grainy patches of light. The eclipsed Moon for m ed a n u p sid e-down (apex pointed down) triangle with blue-white Regulus in Leo and yellow Saturn. Mars, higher in the sky, was coral pink and still slightly brighter than Betelgeuse in Orion. The Moon slipped noticeably away from Regulus and toward Saturn during the eclipse. The appearance of bright sunlight at the lower left of the Moon as 11 p.m. approached marked the end of totality. Again, the edge of the umbral shadow was blurred and indistinct.

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 edi-

Correction
A newsbrief la st m on t h st a t ed t h a t m ost scien tists think the asteroid hit on the Yucatan played a large role in the extinction of 7% of life on Earth. That should have been about 70%.

Amateur Astronomers Association 1010 Park Avenue New York, NY 10028

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