Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.aaa.org/EyepieceFiles/aaa/2009_12_December_Eyepiece.pdf Дата изменения: Sun Feb 22 20:31:02 2015 Дата индексирования: Sun Apr 10 03:45:28 2016 Кодировка: Поисковые слова: equinox

Journal of the Amateur Astronomers Association of New York December 2009 Volume 57 Number 12, ISSN 0146-7662

EYEPIECE
tational repulsion." For this region, then, and the "primordial soup" of formed from the released energy of this point onward standard cosmology inflation stopped ordinary particles that decay. "From takes over."

Inflation: Questions Answered and Unanswered
By Lynn Darsh
"What banged? Why did it bang? And what happened before it banged?" Dr. Alan Guth, Victor F. Weisskopf professor of physics at MIT, provided concise yet sophisticated answers at the AAA's annual John Marshall Memorial Lecture November 6, "Inflationary Cosmology: Is Our Universe Part of a Multiverse?" In a three-part explanation, Guth covered how these questions aren't answered by standard Big Bang theory but by his inflation paradigm: why the universe underwent a process called inflation, and where repulsive gravity ties into dark energy, the still unsolved "key mystery of the universe." "What banged?" Guth proposed that a small patch of material with repulsive gravity exponentially expanded repeatedly in the very early universe. "Why did it bang?" The propulsion mechanism of the Big Bang was the energy of the gravitational repulsion of this material, Guth asserted. The "grand unified theory" of particle physics and general relativity allows for the creation of a repulsive gravity field at high energies. Guth explained that the incredible energy level in the early universe, approximately 1016 GEV around 10-37 second, was great enough to produce material with repulsive gravity. A patch of about 10-28 cm in size would have been large enough to produce our universe. After this material exponentially expanded, before about 10-35 second, doubling in size at least 65 times, the region "destined to become the presently observed universe was about the size of a marble". But it was made of "fundamentally unstable material that decays and turns into ordinary particles produced by decay without gravi-

Before going on to consider the third question of what happened before the Big Bang, Guth discussed the key successes of inflationary theory. The horizon/homogeneity problem: In the kinetics of the Big Bang theory, it's impossible to explain "why the cosmic background radiation is uniform to 1 part in 100,000. To achieve this uniformity without inflation, information and energy must travel about 100 times the speed of light." (This is impossible.) According to what Guth called the "zeroth law of thermodynamics," "put two objects together and they will come to the same temperature." Uniformity is established in a tiny region before inflation, and then inflation magnifies this region to encompass the entire observed universe and more." The flatness problem ("flatness", not meaning twodimensional, but as in Euclidean as opposed to the nonEuclidean curved spaces allowed by Einstein's general relativity). If the early universe were open, no galaxies would form. If closed, the universe would recollapse, and no galaxies would form. For galaxies to form, the early universe had to be very flat: Omega had to be 1. Guth defined Omega as the actual mass density of the universe, divided by the critical mass density (which depends on the expansion rate of the universe). Omega describes whether the geometry of a universe is closed (Omega greater than 1), open (Omega less than 1) or flat (Omega equal to one). "To be as close to critical density as we measure today, at one second after the Big Bang, Omega must have been equal to 1 to 15 decimal Inflation continued on page 11


Whats Up
By Tony Hoffman The Sky for December 2009
Good Year for Geminids. The Moon is a fingernail crescent the morning of December 14 and shouldn't interfere with the Geminids, one of the year's most reliable meteor showers. Observers at dark-sky sites may see more than 100 of these meteors, fragments of asteroid 3200 Phaeton, an hour. Meteor counts from the city should be less, but still respectable. Red Planet Nights. Mars continues to brighten, from magnitude -0.1 to -0.7over the course of the month, as its disk grows to 13 arc-seconds in diameter. The planet rises at 10 p.m. as December opens and by 8 p.m. at year's end. Mars is a denizen of Leo this month. Decembers Constellations. By late December, winter's brightest constellations are well-placed for viewing in the evening sky. Capella rides high in the east as the sky darkens, with Aldebaran well to its lower right. Orion rises in the east in the early evening, with Gemini to its left, rising on its side, and Castor standing almost directly above Pollux. Sirius and Procyon rise a bit later. Sirius is at its highest at midnight on New Year's Eve. Even Leo gets into the act, rising before midnight. The Great Square of Pegasus stands high in the east in the early evening, trailed by Andromeda, Triangulum and Perseus. The Summer Triangle still lingers low in the west-northwest in the early evening. Early next year, Altair, then Vega and finally Deneb will slip into the sunset. Jupiter lingers in the south-southwest in the early evening, shining at magnitude -2.2. Mercury puts in an appearance around mid-month, when it should be visible to the naked eye very low in the south-southwest. Decem Decem Earth), Decem Decem Decem Decem Decem Decem Decem
2

greatest elongation in evening sky. December 18-22 8th-magnitude Neptune is within ѕ degrees of Jupiter, in the same low-power binocular field. December 21 Winter solstice at 12:47 p.m. December 24 First-quarter Moon at 12:36 p.m. December 31 Full Moon at 2:13 p.m.; partial lunar eclipse observable after sunset.

Sunspots Reappear, Disappear
By Joseph A. Fedrick
A long and narrow complex group of sunspots appeared on an image of the Sun projected onto paper with my 60mm refractor on the morning of October 25. This was the first time since July that I was able to observe sunspots despite many observations of the Sun's projected image in the intervening months. The group of sunspots spanned approximately one-eighth of the width of the solar disk. By November 3 the spots rotated off the solar disk and no new spots were visible in the Sun's projected image. Therefore, it appears sunspot activity still continues to be rather sparse. The Moon occulted parts of the Pleaides star cluster on the night of November 3-4. The occultation began shortly after 10 p. m. I observed with 10x50 binoculars and my 60mm refractor. The Moon was just one day past full and the glare of its light prevented observing the disappearance and reappearance of stars at the lunar limb. However, the appearance of the Pleaides and the Moon in my binoculars was quite spectacular in spite of the difficulty in observing members of the cluster that were close to the lunar limb. Mars rose in the northeast and cleared the trees to my east shortly after midnight in early November. Mars had passed the beehive star cluster (M44) November 1 and still appeared in the same field of view as some of the star-cluster members in my 60mm refractor at 50x by November 2 shortly after midnight. Mars had moved only slightly by November 3 and 4. It still presented a spectacular view with the nearby M44 star cluster in my binoculars. Mars appeared as distinctly gibbous at 100x in my 60mm refractor. Although the coral-pink disk of Mars appeared slightly mottled, I still couldn't discern recognizable markings on the tiny but bright Martian disk in poor seeing near the horizon.

ber 2 Full Moon at 2:30 a.m. ber 4 Moon at perigee (225,856 miles from 9:18 a.m. ber 6 Moon lies near Mars. ber 7 Earliest sunset of the year. ber 8 Last-quarter Moon at 7:13 p.m. ber 10 Moon lies near Saturn. ber 13 Geminid meteor shower peaks. ber 16 New Moon at 7:02 a.m. ber 18 Moon lies near Mercury; Mercury at


A Message from AAA President Richard Rosenberg
Hello, members: Thank you if you've already sent in your renewal. If you haven't, please send a check or money order to teur Astronomers Association, Box 383, Gracie Station, New York, NY 10028. Our yearly dues remain $25. tions to Sky & Telescope and Astronomy magazine also are unchanged at $32.95 (one year) for S&T and year) and $60 (two years) for Astronomy. Of course, a donation to the club would be very the AmaSubscrip$34 (one welcome.

The AAA class began in October and ends December 2. This will be followed a week later by an observing session at Ward Pound Reservation in Pound Ridge, Westchester County. We have scopes but are looking for drivers who can give class members a ride. We need drivers because more than 30 people are taking the class. Contact me if you can help. We'll have a wealth of targets, including Jupiter, Andromeda Galaxy, Orion Nebula, Pleiades and Milky Way. If it's cloudy, we'll try a week later. My thanks to board member Shana Tribiano for her excellent job teaching the class. Another special event will be a visit to Belvedere Castle in Central Park at 6 p. m. Sunday, December 20. I'll give a talk on the winter sky, then we'll take a look at it. The targets will be much the same as those at Pound Ridge, but Jupiter and Neptune will be so close together they'll be seen in the same telescopic field of view. We have new banners to announce our presence. One will be on view at our lectures at the American Museum of Natural History starting December 4. Our speaker is Charles Baltay of Yale University. Each year, the club purchases several copies of the Observers' Handbook published by the Royal Astronomical Society of Canada. They're only $17.45, including postage, but supplies are limited. If you're interested, contact me. Rich Rosenberg, AAA President, president @aaa.org, (718) 522-5014

AAA Lecture December 4: ,,The Dark Side of the Universe
Dr. Charles Baltay, Eugene Higgins professor of physics and professor of astronomy at Yale University, will address the AAA Friday, December 4 on "Exploring the Dark Side of the Universe: Accelerating Universes, Dark Matter, Dark Energy and All That." The free public lecture begins at 6:15 p. m. at the Kaufmann Theater of the American Museum of Natural History. Baltay will discuss "our modern view of cosmology: the Big Bang model of an expanding universe, the startling discovery that the expansion of the universe is accelerating and why this state of affairs is incompatible with our existing understanding of nature: a universe full of matter with attractive gravity described by Einstein's theory of general relativity. "The discovery of an accelerating expansion will therefore require a fundamental modification of our present understanding of physical reality: the postulation of a new mysterious dark energy as the dominant constituent of the universe or a revision of our view of gravity, i.e., general relativity. The theoretical and experimental basis of these issues will be discussed in a straightforward, non-mathematical manner. Baltay has held his present position since 1988, and served as chairman of Yale's physics department from 1995 to 2001. He was professor of physics at Columbia University from 1972 to 1988 and served as director of its Nevis Laboratory from 1979 to 1985. Baltay received a Ph.D. in physics from Yale in 1963. His research interests are experimental particle physics, astrophysics and cosmology. The next two dates and speakers are: January 8: Jerry Bonnell, NASA, "Best Astronomy Pictures of the Day, 2009." February 5: Arlin Crotts, Columbia University, "Liquid Mirror Telescopes Are Looking up."
3


Seminar Scrutinizes NASAs Latest Space Mission
By Mary Carlson
Chair, AAA Recent Advances Seminar

At last months recent advances in astronomy seminar, NASA's latest space mission, WISE, captured our attention. An acronym for Wide-field Infrared Survey Explorer, WISE is scheduled for launch this month, destined for Earth orbit. The craft and its telescope are small by mission standards, but its goals are sweeping. It will survey the entire sky in four infrared wavelengths including the key one: mid-infrared. Unique over visible light and even near infrared, mid-infrared wavelengths are sensitive to different properties and will provide a heightened sensitivity to cool objects like asteroids, dust clouds and very distant redshifted galaxies. While asteroids can be seen in visible light, they tend to absorb heat from the Sun and reradiate that heat in the infrared. It's this mid-infrared spectrum that groundbased surveys can't easily access. WISE will provide an indication of an asteroid's true reflectivity, or albedo, a major factor in early detection. Also on WISEs agenda is a search for brown dwarfs, especially very cold ones. They seem to represent the link between gas-giant planets and stars. WISE will probe that thermal area between Jupiter at 125 degrees K. and the coldest currently known brown dwarfs at about 600 K. Additional targets will be ultra-luminous infrared galaxies, those that are extremely bright in mid-infrared light, with a large amount of star formation. These tend to be quite distant. In order for all of this to work, both the WISE telescope and detectors must be kept very cold. Both will be encapsulated in a cryostat cooled by solid hydrogen (an unusual state for hydrogen) to seven degrees above absolute zero. Like many of NASAs previous missions, this explorer might well take us through paths not yet dreamed of. More to come in this space. The seminar also looked at results of Fermi's first year, MESSENGER's latest flyby of Mercury, our solar system's strange new ribbon,
4

Cassini's latest probe of Enceladus and more. If this spikes your interest, please join us. Details of this month's seminar are on page 11.

Its Official: Theres Water on the Moon
Strong suspicions that theres water on the Moon were not only confirmed last month, but big time. NASA's LCROSS probe discovered beds of water ice at the lunar south pole when it impacted the Moon October 9. The $79 million spacecraft hit the lunar surface in an effort to create a debris plume that could be analyzed by scientists for signs of water ice. Those signs were visible in the data from spectrographic measurements of the crater created by LCROSS' rocket stage and the debris plume the probe created. The signature of water was seen in infrared and ultraviolet spectroscopic measurements. That evidence for water was seen in two instruments makes scientists confident in their findings. Based on the measurements, scientists estimated about 100 kilograms of water in the view of their instruments, the equivalent of about a dozen 2-gallon buckets, in the area of the impact crater, about 66 feet across, and the ejecta blanket, 60 to 80 meters across. When melted, the water could potentially be used to drink or to extract hydrogen for rocket fuel. The find made scientists hopeful water could be found elsewhere. And water wasn't the only compound seen in the debris plumes of the LCROSS impact. What exactly those other compounds are hasn't yet been determined, but could include organic materials that would hint at comet impacts. The water ice has potentially been there for billions of years. Several theories have been advanced to explain the origin of the water. These include debris from comet impacts, interaction of the lunar surface with the solar wind and even giant molecular clouds passing through the solar system.


Detective Work on the Moon and the Apollo 11 Landing
By John Delaney
When reading about events of social and historic significance, we rely on the accurate reporting of others. In some instances, it's possible to independently verify facts featured in the stories we read. When accounts of past events incorporate the presence of astronomical bodies such as the Moon and the stars, it becomes possible for news consumers to gauge the accuracy of the stories. In one famous instance, Abraham Lincoln (a lawyer before he was President) was able to exonerate one of his clients from a charge of murder by discrediting a key witness who allegedly observed the defendant murdering the victim under the light of a full Moon. During cross examination of the witness, Lincoln produced a Farmers' Almanac to cast doubt on the testimony, pointing out the Moon wasn't full but a waxing crescent Moon on the date and time of the murder. In the past year, I myself used the online version of the Farmers' Almanac to investigate the accuracy of a recent account involving the Moon and its position in the sky during a significant event. No one's freedom was at stake, but the story focused on one of the 20th Century's defining moments: the Apollo 11 Moon landing. While traveling to work on the subway, I eagerly read The New York Times' July 14 Science Times special section commemorating the 40th Anniversary of the Apollo 11 landing. It was a magnificent account by reporter John Noble Wilford, who covered the landing for The Times and wrote the lead story on it. But one paragraph jumped out at me as potentially incorrect. After a full day of reporting on July 20, 1969, Wilford noted that the time was "going on 3 a.m." on July 21 before he packed his typewriter and notes into a bag and headed for the parking lot. He then wrote: "I stopped to gaze at the full Moon and the dark spot that is the Sea of Tranquility, where Armstrong and Aldrin are settling down after their day in history. What can they be thinking? What joy they must know, and what relief." Fantastic stuff...perhaps a bit too fantastic. I recall reading that Apollo mission planners specifically timed their landings to keep the Sun low on the lunar horizon, presumably to keep surface temperature more manageable for the astronauts. I confirmed on Internet-based simulators that the Moon was in a waxing crescent phase a few days shy of a Quarter Moon during the landing. Soon after, I sent a correction to the Times and received an automatic response stating that a correction, if deemed necessary, would run in the following days. Later that day, I realized that a waxing crescent Moon sets relatively early in the night. Could someone at the Houston Space Center even have seen the Moon in the wee hours of July 21? The question led me to Moon rising-and-setting time data provided through the Farmers' Almanac website for July 1969 for Houston. According to records, the Moon set before midnight on July 20, so how could anyone have seen it early the next morning from Houston? Was I obsessive? Perhaps, but astronomical factors such as the lunar phase during the Apollo landings represent unique opportunities to teach the public about astronomy and the importance of science in the exploration of space. Sending astronauts to the Moon requires an awareness of lunar conditions relating to phases and surface temperatures, so why not correct such errors and use the event to inform readers about the topic? I sent another letter to The Times, this time asserting that the Moon wasn't visible at the time Wilford claims to have seen it. Perhaps the reporter's memory simply amalgamated his Apollo recollections with a full Moon observed later that month. After all, it was 40 years ago. Unlike the print version of the story, the Web version now omits the word "full," but the reporter's online story still has him viewing and pondering the moon from Texas on the morning of July 21. In the context of the story, Wilford's Moon observation is a minor detail in his masterful account of a defining moment. But his specificity on seeing the Sea of Tranquility at that place and moment seems embellished, even contrived, when reliable sources such as the Farmers' Almanac reveal that the Moon was just not visible from Mission Control at that time.
5


The Sun Is Much More Complicated than It Appears
By Edward J. Fox
A group of astronomers and physicists is interested in studying the complexities of the weather on the Sun. This was the subject of a Hayden Planetarium lecture October 19 when Juri Toomre, professor of astrophysics at the University of Colorado, Boulder, spoke on "Touching the Heart of Magnetism in Our Nearest Star." Toomre discussed the latest advances and the close interplay between recent 3-D simulations and helioseismology, the study of the propagation of pressure waves in the Sun. According to Toomre, this is "the study of the shakes and quivers" of the Sun. Unlike surface seismic waves on Earth, solar waves have practically no shear component and this affects the complex interplay of these waves within the Sun. The research is an attempt to understand the complex operation of solar magnetism and its effects on the Earth. First, Toomre explained, it's important to understand the immense size of the Sun. The Sun has a radius of approximately 695.5 mega-meters (a unit of measure, not normally used, but applied only to the largest objects) or 695,500,000 meters (432,163 miles, or about 54 Earth diameters), and is comprised of a number of vastly differing layers. The layers of the Sun are studied to understand their interrelationships. The outermost layer, the near-surface shear layer, occupies a distance of 5% of the radius. The other layers, at increasing depths, are the convection layer, the radiative zone and the core. The outer layer is so granular and complex it cannot be modeled even with with today's technologies. The Sun's inner layers are larger and less granular, and as such are able to be simulated using super-computers. One interesting result of the interplay of the layers is that the Sun's rotation differs from the equator to the poles. The area near the equator rotates once every 25 days. The latitudes near the poles rotate once every 36 days. It's well known that the Sun's internal activities cause sunspots to appear on the surface and their
6

frequency varies over a period current cycle is at a low point in In fact, the reappearance of suns late, compared to a normal 11 Sun cycle is Cycle 24.

of about 11 years. The the number of sunspots. pots is a couple of years year-cycle. The current

Sunspots are the sites of spectacular explosive events, including solar flares and coronal mass ejections, which are associated with eruptions of plasma. It's important to understand these disturbances, since radiation and plasma from these events sweep past the Earth and can disrupt spacecraft, radio communications and power systems. Modern systems are increasingly sensitive to solar disturbances. Toomre and his associates study these variables to further understand the Sun and other stars. They would like to be able to predict solar activity. One tool they use is the study of solar sound waves. The researchers can actually use sound waves to "see" sunspots on the far side of the Sun. This is the equivalent of sonograms of the Sun. The Sun is studied using a variety of solar diagnostics. Observations include the frequency-splitting of fiveminute oscillations of the Sun search for subphotospheric flows, large-scale structures and differential rotation in the convection zone. Inverse theory has been developed to interpret the data. The Global Oscillations Network Project uses six ground-based Doppler imaging instruments to obtain nearly uninterrupted observations of solar oscillations, which are complemented by observations from space. Animations are created to show variations in activity at various internal levels over time. These are analyzed through simulation, in the use of vector supercomputers, massively parallel machines, high-speed networks and major visualization systems. Toomre and colleagues are learning about the Sun's life cycle, which in turn helps them learn about stars and the universe. For more information on Toomre's work visit the JILA site, Structure and Evolution of Stars, at: http://jilawww.colorado.edu/research/structure.html.


Astronomy Books for Holiday Gift Giving--Or Just for You
Eyepiece can't review all astronomy books, especially with so many titles these days. So in time for holiday gift giving, or just for you, here's a roundup of some recently published books.--Dan Harrison Unless youve been hibernating, you know that 2009 has been the International Year of Astronomy. "Eyes on the Skies: 400 Years of Telescopic Discovery" by Govert Schilling and Lars Lindberg Christensen (Wiley-VCH, $29.95) takes us from pre-Galileo onward. Highlighted q u ot es u nd er sc or e ho w f ar we' ve co me : "Astrophotography turned observational astronomy into a true science." "In a few years, anyone will be able to explore the cosmos from a laptop." "Studying the universe using visible light alone is like attending a concert with a severe hearing problem." Galileo also comes to the fore in "Galileo's New Universe: The Revolution in Our Understanding of the Cosmos" by Stephen P. Maran and Laurence A. Marschall (BenBella Books, paper, $14.95). This short book concisely ranges from ancient astronomy to the possibility of life in outer space. Our nearest neighbor gets extraordinarily comprehensive treatment in "The Book of the Moon" by Rick Stroud (Walker, $27). There are abundant facts and figures, lots of history, gods and myths, and much more. From the Moon, one can travel to see the rest of the solar system, via "The New Solar System: Ice Worlds, Moons and Planets Redefined" by Patricia Daniels (National Geographic, $35). Aimed at a popular audience, the book features contributions by former Astronomy editor magazine Robert Burnham and includes what to expect in the future, including the upcoming Moon mission and the likelihood of a manned Mars expedition. For the basics on observation, there are three titles: The excellent "From Here to Infinity: A Beginner's Guide to Astronomy" by John Gribbin and Mary Gribbin (Sterling, $24.95) includes chapters on cosmology, and life and the universe. There's also "Backyard Guide to the Night Sky" by Howard Schneider (National Geographic, $21.95) and "Stargazing Basics: Getting Started in Recreational Astronomy" by Paul E. Kinzer (Cambridge, paper, $18.99). Astrophotography books are almost guaranteed to dazzle. Two are particularly striking. "Ancient Light: A Portrait of the Universe" by David Malin (Phaidon Press, $49.95) is black and white. Malin believes "black and white is the essence of photography. It's about light and shade, shape, texture and the subtlety of tone. All these ingredients exist in a colour photograph, but black and white allows their full expression." Another winner is "Capturing the Stars: Astrophotography by the Masters" by Robert Gendler (Voyageur Press, $30). The images are color, with 35 photographers represented. Many an astronomical newbie is told to buy binoculars before sinking a lot of dough into a telescope. A useful guide is "Viewing the Constellations with Binoculars: 250+ Wonderful Sky Objects to See and Explore" by Bojan Kambic (Springer, paper, $39.95). It's written for beginners and intermediate-level astronomers. Also on the subject is "Stephen James O'Meara's Observing the Night Sky with Binoculars: A Simple Guide to the Heavens" (Cambridge, paper, $29.99). The bulk of the book is on stars to see by season. If youre beyond newbie status, Springer, which publishes an abundance of astronomy titles, has many books that may be of interest. Two examples: "Choosing and Using a New CAT: Getting the Most from Your Schmidt Cassegrain or Any Catadioptric Telescope" by Rod Molisse ($29.95) and "Building a Roll-Off Observatory: A Complete Guide for Design and Construction" by John Hicks ($59.95). You like 3-D? Try "Mars 3-D: A Rover's-Eye View of the Red Planet" and/or "Moon 3-D: The Lunar Surface Comes to Life." Both are by Jim Bell (Sterling, $19.95). Those yellow books for dummies now include "Space Exploration for Dummies" by Cynthia Phillips and Shawna Priwer (Wiley, paper, $19.99). The book evolves chronologically and includes the future. You havent had enough of the Pluto controversy? Slake your thirst with "Pluto Confidential: An Insider Account of the Ongoing Battles Over the Status of Pluto" by Laurence A. Marschall and Stephen P. Maran (BenBella Books, $14.95). The astronomers were on opposite sides of the debate on whether to demote Pluto.
7


Briefs: Star is Most Distant Object Ever Observed
Light from a star that exploded 13 billion years ago has been detected, becoming the most distant object in the universe ever observed. Light from the gamma-ray burst, GRB 090423, surpassed the previous recordholder, GRB 080913, 12.8 billion light-years distant. This means the gamma-ray burst occurred just 630 million years after the theoretical Big Bang, when the universe was 4% of its current age. Detecting the most distant galaxies and quasars from this period is difficult, so astronomers hope distant gamma-ray bursts will provide definitive information about this cosmic dark age. The most distant known galaxy cluster has been discovered by Chandra 10.2 billion light-years away. JKCS041 beats the previous record holder, XMMXCS J2215.9-1738, by about 1 billion light-years. JKCS041 is found at the point when scientists think galaxy clusters began to exist based on how long it should take for them to assemble. JKCS041's component galaxies were detected in 2006. The distance to the cluster was then determined from optical and infrared observations. Chandra data were the final piece of evidence that JKCS041 was a genuine galaxy cluster. The extended Xray emission seen by Chandra shows hot gas between the galaxies, as expected for a galaxy cluster rather than one that's been caught forming. A gigantic, previously unknown set of galaxies has been found in the distant universe. The most widely accepted theories predict matter also clumps on a larger scale in the so-called cosmic web, in which galaxies, embedded in filaments stretching between voids, create a gigantic wispy structure. These filaments are millions of light-years long. A team discovered a large structure around a distant cluster of galaxies in images taken earlier. They have now measured this structure in greater detail, measuring distances from Earth to more than 150 galaxies, and, hence, obtaining a three-dimensional view of the structure. With these observations, astronomers identified several groups of galaxies surrounding the main galaxy cluster. They were able to distinguish tens of such clumps, each typically 10 times as massive as the Milky Way, some as much as 1,000 times more massive. The filament is 6.7 billion light-years away and extends at least 60 million light-years. Basic molecules required for life as we know it have
8

been detected in a second hot-gas planet beyond our solar system. The planet orbits a Sun-like star about 150 light-years away in Pegasus. Although uninhabitable, it has the same chemistry that, if found around a rocky planet, could indicate a world that might support life. Water, methane and carbon dioxide have been found. Because organic compounds have been detected in two exoplanets, it may become commonplace to find planets with molecules that may be tied to life. The relative amounts of water and carbon dioxide in the two planets is similar, but the one in Pegasus shows a greater abundance of methane. If such Earth-like planets are found, detection of organic compounds won't necessarily mean there's life on a planet because there are other ways to generate such molecules. A new type of supernova has been discovered in which helium detonates on the surface of a white-dwarf star. The exploding star, SN2002bj, was first observed seven years ago in the galaxy NGC 1821 by amateur astronomers, but was misclassified as a Type II supernova. SN2002bj had a different signature than any variations known in Type I or Type II supernovas. It brightened and dimmed over less than 27 days, whereas most supernovas brighten and dim over three or four months. The supernova was rediscovered through a search of old observations. Rapid dimming of the supernova and certain signatures in its spectrum, such as a strong helium signal, indicate a unknown mechanism exploded this star. It's thought that in a binary pair of white dwarfs, one primarily made of helium is having the gas slowly siphoned off by its companion. When enough helium accumulates on the surface of the main white dwarf, an explosion powers a faint and brief thermonuclear supernova. A new survey has found 22 of the earliest galaxies to form in the universe, confirming the age of one at just 787 million years after the Big Bang. Astronomers don't know when the first stars and galaxies began to illuminate the universe except that it was before the universe was 1 billion years old. This time, they studied an area more than 100 times larger than earlier studies. A series of newly discovered depressions on Mars could be the entrances to a cave system. Hints of subsurface tunnels were found in prior images, but new evidence is more suggestive. Such a system could provide Continued on page 9


Briefs: Spacecraft Will Sail on Sunlight Alone
Continued from page 8 shelter to astronauts and a protective habitat to potential past or present Martian microbes. Signs of "collapse depressions" in extinct lava flows from a volcano were found in high-res images taken by orbiting spacecraft. The grooves are 62 miles long and up to 330 feet across; the apparent skylights are up to 160 to 200 feet across. The grooves likely formed when a solid ceiling of cooled material formed over a lava channel during an eruption. The Planetary Society last month announced LightSail, a plan to sail a spacecraft on sunlight alone by the end of 2010. LightSail, boosted by a $1 million anonymous donation, will launch three spacecraft over several years. The first will demonstrate that sunlight alone can propel a spacecraft in Earth orbit. The second and third will reach farther into space. To get sunlight to push a craft through space, it needs a large sail attached to a small spacecraft. The first craft fits into a volume of three liters before the sails unfurl to fly on light. LightSail seeks to prove solar-sail technologies in a few years can monitor the Sun for solar storms, provide stable Earth-observation platforms and explore the solar system without heavy propellants. Sailing on light pressure, from lasers and not sunlight, is the only known technology that might carry out practical interstellar flight. Reflected light pressure, not solar wind, propels solar sails. An October space-rock explosion over Indonesia was perhaps the biggest object to hit Earth in more than a decade. On October 8, reports told of a loud air blast. One report indicated a bright fireball, accompanied by an explosion and lingering dust cloud, as the origin of the blast. An asteroid, more than 30 feet in diameter, may have blown up due to atmospheric pressure. This is thought to have yielded an energy release of about 50 kilotons (equal to 110,000,000 pounds of TNT). This may have been the largest object to strike Earth in 15 years. It's not unusual for Earth to be hit every decade or so by such an object. The supernova remnant Cassiopeia A, one of the youngest in our galaxy, is likely a neutron star swathed in a carbon atmosphere, a new study finds. Cassiopeia A, a remnant of the explosion of a star that once shone brightly, is believed just 330 years old. Astronomers didn't get their first up-close glimpse of the core remnant, about 11,000 light-years away, until 1999, when Chandra imaged the collapsed star. Scientists think the star was able to conduct nuclear fusion on its surface and burn hydrogen and helium into carbon. As the star gets older, it will cool rapidly and eventually stop burning the elements into carbon and develop a hydrogen atmosphere. Striking new photos of water-vapor geysers erupting from Enceladus were taken by Cassini, in orbit around Saturn. Cassini made its deepest dive into the plumes pouring from the moon's south pole last month, approaching within 62 miles. The powerful plumes contain water vapor, sodium and organic chemicals such as carbon dioxide. The aim of the flyby, Cassini's seventh toward Enceladus, was to measure size, mass, charge, speed and composition of the plume's particles. A NASA spacecraft spotted what appears to be changing seasons on Mercury and found much more surface iron than thought. The probe's third flyby brought it within 142 miles and was a gravity assist to guide the spacecraft into orbit in 2011. Mercury's atmosphere is made up of atoms kicked up from the surface. It's tenuous and has very low density, meaning atoms in the atmosphere rarely run into each other. MESSENGER looked at differences in three atoms in the exosphere-sodium, calcium and magnesium--between the three flybys and detected much less sodium during the last. The flybys also provided the first direct measurements of the amounts of some elements on the surface, and images of a feature seen before, but not in detail. This seems to be a bright area surrounding an irregular depression, with steep sides and an odd shape, all hallmarks of something like a volcanic vent. Other images revealed a double-ring impact basin 180 miles across. Recent photographs of an active galaxy offer new confirmation that supernova explosions create surprisingly energetic particles called cosmic rays. Cosmic rays originate far beyond the solar system, but when some make it past Earth's atmosphere they can carry such a punch they knock out electronics systems. M82's density of cosmic rays was 500 times that of the Milky Way.

Continued on page 10
9


Continued from page 9 A young star observed by Spitzer seems to be home to a wild, young planetary system that's being molded by some forces believed to have shaped the early solar system. Observations suggest young planets circling the star are disturbing smaller comet-like bodies, causing them to collide and kick up a huge halo of dust. Ground-based telescopes took images of three planets orbiting in the far reaches of the system, HR 8799, each about 10 times Jupiter's mass. HR 8799, younger and more massive than the Sun, is 129 light-years from Earth. The giant cloud of fine dust around the disk is very unusual. Researchers think it's coming from collisions among small bodies. The gravity of the three planets is throwing the smaller bodies off course, making them collide. A giant composite image of the Milky Way's center has been taken by Hubble, Spitzer and Chandra. It combines near-infrared from Hubble, infrared from Spitzer and X-ray from Chandra. Experts assembled the image from large mosaic photo surveys taken by each scope. The composite features the spectacle of stellar evolution: from regions of star birth, to young hot stars, to old cool stars, to black holes. Infrared light reveals more than 100,000 stars along with glowing dust clouds that create complex structures including compact globules, long filaments and finger-like "pillars of creation," where new stars begin to break out of dark, dusty cocoons. A new panoramic image of the full night sky with the Milky Way as its centerpiece has been made by piecing together 3,000 photographs taken in South Africa, Texas and Michigan. The image shows stars 1,000 times fainter than the human eye can see, as well as hundreds of galaxies, star clusters and nebulae. The search for exoplanets may be a little easier, thanks to a new comparison of Sun-like stars that's revealed a key difference in the chemistry of stars that have planets and those that don't, and solved a longstanding mystery about our Sun's chemistry. The solar mystery revolves around the abundance of lithium in the Sun. Lithium isn't readily produced in stars. It's thought it was mainly produced just after the Big Bang. Astronomers see a range of lithium levels in Sun-like stars. Because there seemed to be no way for Sun-like stars to burn off this lithium, astronomers were left with a conundrum. But by looking at Sun-like stars in a survey, one10

fourth had an lar to t levels.

of the total sample, astronomers found those that orbiting planetary system had lithium levels simihe Sun's, while those that were barren had higher Why stars with planets lack lithium is a mystery.

The Suns surface has been imaged in unprecedented detail. Images of transient dark spots, the Sun's seemingly granulated texture and moving packets of gas were snapped by the SUNRISE balloon-borne telescope. SUNRISE dangles from a helium balloon 24 miles above Earth. Stratospheric observing conditions are similar to space's. Of particular interest is the connection between the strength of the Sun's magnetic field and the brightness of tiny magnetic structures on its surface. Variations in solar radiation are particularly pronounced in ultraviolet. SUNRISE carried out the first study of bright magnetic structures in this range of the Sun's spectrum.

Hail to Astronomy
President Obama White House October amateurs set up more family and local middl welcomed schoolchildren to the 7 for stargazing. Professionals and than 20 scopes. Mr. Obama, his e-school students attended.

The White House said the star party was aimed at highlighting "the President's commitment to science, engineering, and math education...and to express his support for astronomy, for its capacity to promote a greater awareness of our place in the universe, expand human knowledge and inspire the next generation by showing them the beauty and mysteries of the night sky." The idea behind the star party originated with Chicago amateur astronomer Audrey Fischer.

Correction
Due to an editing error, last month's story on Dr. Michael Way's October 2 AAA lecture didn't give his full title, simply noting he's with NASA. Way is an astronomer/computer scientist at NASA's Ames Research Center and its Goddard Institute of Space Studies.

Contacting the AAA
If you want to join, volunteer, participate in events, have a question or change your address, e-mail members @aaa.org, or leave a message at: (212) 535-2922. Also, visit us on the web at www.aaa.org.


Events on the Horizon December 2009
M: members; P: open to the public; T: bring your telescopes, binoculars, etc.; C: cancelled if cloudy; HQ: at AAA headquarters, Downtown Community Center, 120 Warren St. AMNH: For ticket information, call (212) 769-5200 For directions to AAA observing events, check the club's website, www.aaa.org. Wednesdays, December 2, 9, 16, 23, 30, and Saturdays, December 5, 12, 19, 26, 8:30-10:30 p. m Observing, Inwood Hill Park, Manhattan, P, T, C Next dates: Wednesdays and Saturdays in January. Wednesday, December 2, 6:30-8:30 p.m. Last meeting, AAA Class, HQ Friday, December 4, 6:15 p. m. AAA lecture, FREE, P Dr. Charles Baltay, professor of physics and of astronomy at Yale, will discuss "Exploring the Dark Side of the Universe: Accelerating Universes, Dark Matter, Dark Energy and All That" in the Kaufmann Theater of the AMNH. Next lecture: January 8. Friday, December 4, 7:30-9:30 p. m. Observing, Floyd Bennett Field, Brooklyn, P, T, C On the model airplane flying field. Monday, December 7, 7:30 p. m. Hayden Planetarium lecture, P, AMNH Richard Greenberg, professor of planetary sciences at the University of Arizona, will discuss "Unmasking Europa: The Search for Life on Jupiter's Ocean Moon." Wednesday, December 9, 6:30 p.m. Observing, Ward Pound Reservation, Westchester County, P, T, C Observing session for class members. Meet at headquarters or a prearranged meeting point to be determined. Rain date: December 16. Thursday, December 10, 6:30-8:30 p. m. Recent Advances in Astronomy Seminar, M, HQ Pre-meeting dinner at 5:15 at the Gee Whiz Diner, Warren and Greenwich streets. Next date: January 14. Saturday, December 19, 10-noon Solar Observing, Central Park, P, T, C At the Conservatory Waters, Next date: January 30. Sunday, December 20, 6-8 p.m. Observing, Belvedere Castle, Central Park, P, T, C Special observing session with Parks Department and Urban Park Rangers. A short lecture on the winter sky will be followed by observing. Tuesday, December 29, 6:30-8:30 p. m. Observers Group, M, HQ Pre-meeting dinner at 5:15 at the Gee Whiz Diner, Warren and Greenwich streets. Next date: January 26. Inflation continued from page 1 places...Since inflation makes gravity become repulsive, the evolution of Omega changes, too. Omega is driven towards one, extremely rapidly. It could begin at almost any value." Density fluctuation problem: In order for the largescale structure of our universe to form, there must have been "very weak ripples in its mass density." How did they form? According to inflation, ripples, or nonuniformities, arose from quantum fluctuations at the end of the inflationary period. These small ripples on top of the uniform distribution of matter were magnified by gravity to eventually form galaxies and galaxy clusters. Since quantum theory is a probabilistic, not predictive, theory, it makes a generic prediction for the shape of the Inflation continued on page 12
11


Inflation continued from page 11 spectrum of the radiation left over from the early universe. "So far, inflation is in perfect agreement with the data brought back from COBE and WMAP." Observational evidence from these satellite probes corroborates the predictions that inflation makes about how density varies with wavelength in the cosmic microwave background radiation. (For details, view Guth's lecture slides on the AAA website, www.aaa.org). But observational evidence also shows that the universe has been accelerating for 5 billion years. Repulsive gravity--and inflation--is still active, and "the repulsive gravity material, which apparently fills space, is called dark energy." Guth's simplest explanation for this stillmysterious force is that it's vacuum energy, or Einstein's cosmological constant. Since Einstein was convinced the universe was static, he balanced his equations by adding the cosmological constant to provide for universal repulsion. Classical physics saw the vacuum as empty, but quantum physics sees vacuum energy as the lowest possible energy state, which is actually not empty but a "seething mass of fields and particles appearing and disappearing," Guth said. However, quantum theory estimates a vacuum energy density that's too large by 120 orders of magnitude. What's causing vacuum energy density to, in fact, be so much smaller than predicted? Guth mentioned that inflation stopped for the region of space that was to become the observable universe, but not everywhere. The universe continues to expand exponentially, and "the inflation becomes eternal....The inflating region never disappears, but pieces of it undergo decay and produce pocket universes...an infinite number ...a multiverse." What happened before the Big Bang, and what's the future of our universe? Guth stated that we're living in a very unusual place. The average mass density of our location is much higher than the average mass density of the universe and the cosmological constant is very small.

Why? Is it time to consider accepting the Anthropic Principle (environmental-selection effect)? "In
some...pocket universes, the energy density would be as small as what we observe....You can also argue that life preferentially forms in those and then you...have an explanation for why vacuum energy density we see is so small." Guth's third question isn't yet fully answered.

Amateur Astronomers Association Gracie Station P. O. Box 383 New York, NY 10028

Forwarding and Address Correction Requested 12

First Class