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Journal of the Amateur Astronomers Association of New York September 2009 Volume 57 Number 9, ISSN 0146-7662

EYEPIECE

Eclipsed by Clouds, and Other Chinese Adventures
By Tony Hoffman
In mid-July, I went to China on t h e P la n et a r y Society's eclipse tour, to see the 21st Century's longest total solar eclipse from near Shanghai. Although the eclipse didn't turn out the way we'd hoped, it was an unforgettable trip with astronomical and terrestrial adventures.
On our first full day in China, after spending the morning at the Forbidden City, we went to a lesserknown but fascinating museum, the Beijing Ancient Observatory. On the old Ming Dynasty-era city wall that once encircled Beijing, this pre-telescopic observatory contains ornate bronze astronomical instruments: sextants, armillary spheres, theodolite, quadrant and more. One large armillary sphere, decorated with four dragons, is a particular beauty. Beijing's original observatory was built in 1227. The current structure was completed in 1442. The instruments on display were rebuilt from older versions in the 1670s by the observatory's director, Jesuit missionary Ferdinand Verbiest. From Beijing, we flew to Xi'an, a for m er ca p it a l of China that around 700 A. D. was the world's largest city. On our last night there, our tour's leader told me he'd come across a man with a telescope showing people Jupiter a few blocks from our hotel. My curiosity piqued, I went for a walk through the city's Muslim quarter until I reached the place where he'd encountered the man. I was surprised to find no fewer than five large telescopes, each with a mirror about 10 inches in diameter. I had a look through two of them, paying 10 yuan (about $1.50) to each of their owners. The view through the first scope was poor, with glare from stray light rendering Jupiter's Galilean moons all but invisible. Before I looked through the second telescope, its owner handed me a small, dark slab of glass. I

couldn't figure out what it was until the owner pointed to the side of his scope, to which he had taped a picture of a solar eclipse. I realized that he was giving me a solar filter--a piece of smoked glass--through which I could view the eclipse four days hence, and it came in handy.
The view through the second scope wa s m u ch better, revealing three of Jupiter's moons and several cloud belts. As I looked at our largest planet late in the evening of July 18, I had no way of knowing that in the hours to come, an asteroid or comet would collide with Jupiter, leaving a dark blemish that would be discovered by an Australian amateur the following night. If the impactor had been a bit further along in its plunge towards Jupiter, it's possible that I would have been able to view the collision or at least its immediate aftermath. From Xi'an, we flew to Hangzhou, a city southwest of Shanghai. Although Hangzhou was in the eclipse path, we'd planned to move on and view the eclipse from a beach at Jinshanwei, nearer Shanghai. Our leaders were having second thoughts due to increasingly poor weather prospects. They considered staying in Hangzhou for the eclipse, but instead forged on to Jinshanwei. After a night of thunderstorms, eclipse day, July 22, began with a solid overcast. Nonetheless, we went to a beach we'd reserved for eclipse-watching. Although the clouds briefly thinned enough for us to see the partially eclipsed Sun from time to time, and I got some decent photos, the clouds closed in again 10 minutes before the start of totality, so we were denied any view of the totally eclipsed Sun in the otherwise dramatic midmorning darkness. Within 15 minutes of the end of totality, it was pouring rain. We quickly left the beach and headed to Shanghai. I felt bitterly disappointed. We'd been teased by the (Eclipsed continued on page 6)


What's Up
By Tony Hoffman The Sky September 2009
September's Constellations. T h e h ea r t of ou r ga la xy is well-placed for observing early on September evenings, with Scorpius to the southwest and Sagittarius in the south. Cassiopeia rises in the northeast, Cygnus stands high in the east and Lyra lies at the zenith. The Milky Way spans these constellations, flowing through Aquila and Ophiuchus down to the center of the galaxy. From the city, binoculars will show a hint of the Milky Way's star clouds and clusters, while dark-sky sites will reveal our galaxy in all its glory. Orange Arcturus twinkles in the west, with Hercules following Bootes westward, while the Big Dipper swings down into the northwest. The Great Square of Pegasus climbs in the east, trailed by Andromeda and Perseus. To the southeast, Jupiter blazes in Capricornus at magnitude -2.8. (For nearly two hours on the night of September 2-3, none of Jupiter's Galilean moons will be readily visible, with Io and Callisto passing behind the planet, and Europa and Ganymede in transit across its face.) Fomalhaut twinkles blue-white, well to Jupiter's lower left. Even Capella and the Pleiades get into the act, rising before midnight. Juno at its Best. O n Sep t em b er 17, Ur a n u s reaches opposition near the circlet of Pisces. At magnitude 5.7, it's an easy enough binocular target for urban observers, and can even be seen with the naked eye by keen-eyed observers from dark-sky sites. While Uranus is a giant planet, a much smaller world also glides through southern Pisces. Asteroid 3 Juno comes to opposition September 21, when it will glow at magnitude 7.6, and should be visible in binoculars from the city on a good night. While asteroids such as Ceres and Vesta become fairly bright every time they reach opposition, the relatively small Juno is easily visible only when it passes particularly close to Earth, as it does this year. September 2 Moon lies near Jupiter. September 3 Between 12:43 and 2:29 a. m., none of Jupiter's Galilean moons are easily visible. September 4 Full Moon at 12:03 p.m. September 11 Last-quarter Moon at 10:16 p.m. September 13 Moon lies near Mars.
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September Earth, 3:56 September September September September September September September

16 Moon at perigee, 226,212 miles from p.m.; Moon lies near Venus. 17 Uranus at opposition. 18 New Moon at 2:44 p.m. 20 Venus lies near Regulus. 21 Asteroid 3 Juno at opposition. 22 Autumnal equinox at 5:19 p.m. 26 First-quarter Moon at 12:50 a.m. 29 Moon lies near Jupiter.

Jovian Observations
By Joseph A. Fedrick
While observing Jupiter on t h e n igh t of J u ly 14-15 between 11:45 p. m. and 1 a. m., I saw a dark black spot transiting the Jovian disk between the equatorial belts. The spot was near the Jovian meridian around half past 12. I observed the spot first with my 6-inch reflector at 150x and then with my 60mm refractor at 100x. I checked the timetables from skyandtelescope.com and found this was a shadow transit of Ganymede, the largest Jovian moon. Ganymede's shadow appeared bigger and darker than the shadows of other Jovian satellites that I observed transit the Jovian disk during August and September 2008. Four nights later (the night of July 18-19), I observed Jupiter from 11:20 p. m. to 12:30 a. m. using my 6 -inch reflecting telescope. I saw the Great Red Spot--which actually appeared rather small and very pale tan-transiting the Jovian disk. The spot fit into a notch in the South Equatorial belt, the so-called red spot hollow. Unfortunately, as Jupiter travelled westward across the sky, it drifted behind a tree in my line of sight. Had I been able to watch it for two more hours, I might have been able to see the new Jovian black spot discovered by Australian amateur astronomer Anthony Wesley nine hours after I quit watching Jupiter. The new spot was following the Great Red Spot by two to two-and-a-half hours so it would have transited the Jovian meridian 22:30 a. m. Virtually all other opportunities to see the new spot were clouded out. Images of Jupiter reveal the spot is black, in high southern latitudes and quickly began to smear out and fade. The spots therefore probably will have virtually disappeared by the time our hazy, cloud weather pattern changes enough to allow making more Jovian observations.


A Message from AAA President Richard Rosenberg
Hello, members: September is here. Let's hope the weather improves. Almost every observing session I was planning to attend this summer was canceled. The only exception was the Movies with a View series at Brooklyn Bridge Park. Even they had two rainouts, and have extended their series for an extra showing on September 3. I am happy to announce the resumption of our class. The instructor will be Shana Tribiano, an AAA board member and associate professor at Borough of Manhattan Community College. The exact dates are still to be worked out. Soon it will be possible to receive Ey epiece via email. This will save us expense and effort, and help the environment. If you don't have e-mail or wish to receive a hard copy of Ey epiece, you will still get it by snail mail. The club recently purchased a CCD eyepiece, using funds from the Fred Hess Memorial Fund. Light captured by a telescope is sent through the CCD and onto a monitor. The CCD is extremely efficient at capturing photons of light so images are brighter. This will allow several people to view an object simultaneously, and for an experienced observer to point out lunar craters, moons of Jupiter, stars in the Pleiades, etc. to newcomers. We hope to have it ready for Starfest September 26. Our annual Urban Starfest on Saturday, September 26 will be from 7:30 to 10 p. m. in the Sheep Mea tral Park. Rain date is the following evening. If you are planning to bring a scope, free parking adjacent to is available (send me your name, make and year of car, and license plate). The Moon and Jupiter will be objects, but targets will include Neptune, Uranus, the Andromeda Galaxy, star clusters and nebulae. Bring -- this is a great occasion to introduce them to the night sky. dow of Centhe meadow the featured your friends

We have a new observing site in the city. It's the High Line, the elevated former rail line in Manhattan. Organized by board member Joe Delfausse, we'll observe there every Tuesday (when weather permits). We'll have at least one scope set up. Information and maps are at http://www.thehighline.org/. If you don't have Internet access, contact me. The New York Times a sked me to pa r ticipa te in its Ask About fea tur e the week of August 24. The subject wa s a stronomy, and they wanted me to answer questions submitted by the public. I was happy to do so. Selected questions and answers appeared in the newspaper and online. If you want to see them, check aaa.org or contact me. Rich Rosenberg, AAA President, president @aaa.org, (718) 522-5014

`100 Years of Cosmology' Kicks Off AAA Lectures Oct. 2
Michael Way, astronomer/computer scientist a t NASA's Ames Research Center and its Goddard Institute of Space Studies, will give the first lecture of the AAA's 2009-10 lecture series Friday, October 2 when he discusses "100 Years of Cosmology: From Spiral Nebulae to the Cosmic Microwave Background." The free public lecture is at 6:15 p. m. at the Kaufmann Theater of the AMNH. Other dates and speakers are: November 6: Ala n G u t h , M I T , "Inflationary Cosmology: Is Our Universe Part of a Multiverse?" (John Marshall Memorial Lecture); December 4: C h a r les Ba lt a y, Ya le Un iver sit y, "Exploring the Dark Side of the Universe: Accelerating Universes, Dark Matter, Dark Energy and All That"; January 8: J er r y Bon n ell, NASA, "Best Astronomy Pictures of the Day, 2008"; (Lectures continued on page 10)
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Recent Advances Seminar Tracks Variety of Missions
By Mary Carlson
Chair, AAA Recent Advances Seminar

As predicted at the AAA's annual meeting, the excitement continues as the Recent Advances in Astronomy Seminar pursues the progress of what's up in our part of the cosmos. The European Space Agency's dual missions, Herschel and Planck, are well underway in opening up new cosmological doors. We're following the Herschel Space Observatory as it achieves targeted milestones. "First light" observations were obtained by its primary instruments: PACS (Photodetector Array Camera and Spectrometer), SPIRE (Spectral and Photometric Imaging Receiver) and HIFI (Heterodyne Instrument for the Far Infrared). Photometric surveys of the galactic and extragalactic sky, detailed studies of the physical and chemical composition of gas, dust and the interstellar medium, and spectroscopic/photometric studies of solar-system objects are on track. PACS' photometer and integral-field spectrometer observed the planetary nebula NGC 6543 (Cat's Eye Nebula), looking at the spectral lines of doubly-ionized nitrogen and neutral oxygen. This demonstrates the capacity for probing the physical properties and chemical composition of objects and their surroundings. SPIRE's camera has centered on galaxies, including M66 and M74, looking for emissions from clouds of dust in regions where stars are forming in our own and in other galaxies. HIFI is detecting ionized carbon, carbon monoxide and water in star-forming regions. Planck's goal is to answer fundamental questions about how the universe came to be and how it will change in the future. Working in the microwave wavelength, it will measure minute variations in the cosmic microwave background and take us back to that fraction of time after the Big Bang. With the spacecraft's cooling system reaching its ultimate operational capacity at 0.1 degree above absolute zero, its High Frequency Instrument and Low Frequency Instrument are operational.
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Herschel and Planck are in separate orbits around the second LaGrange point. At another session, Rich Rosenberg unraveled the mystique of the recent total solar eclipse. As it was beyond our range of view, he guided us on a virtual tour through the event. With the Earth at aphelion, the Sun at 3l.5 arc minutes and the Moon at perigee and at 33.7 arc minutes, totality was assured. We saw a speeded up version of the six minutes of totality. We then transitioned to the Lunar Reconnaissance Orbiter (LRO) and the Lunar Crater Observation and Sensing Satellite (LCROSS). LRO, in lunar orbit, is transmitting images of the lunar surface through its two cameras, a low resolution wide-angle camera and a high resolution narrow angle camera, collectively known as the Lunar Reconnaissance Orbiter Camera (LROC). The first images were along the Moon's terminator. LRO will help NASA identify safe landing sites for future explorations, locate possible resources, analyze the Moon's radiation environment and initiate new technologies. Additional instruments have been activated and calibrated: the Lunar Exploration Neutron Detector to search for regions with enriched hydrogen for possible waterice deposits, the Cosmic Ray Telescope to measure the Moon's radiation, the Laser Altimeter to build 3D topographic maps, the Diviner Lunar Radiometer to make temperature maps of the lunar surface, a Miniature Radio Frequency Transmitter to search for subsurface ice and to prepare detailed images of permanently shaded areas using radar and radio waves, and the Lyman Alpha Mapping Project. Its ultraviolet-light imager will use starlight to search for surface ice in deep craters at the poles. LRO's lunar orbit, initially 18 miles over the South Pole and 124 miles over the North Pole, will eventually maintain a 31-mile circular orbit. (Seminar continued on page 12)


Observing Our Nearest Neighbor--and More
By Jason Kendall
On August 1, it was "IYA Observe the Moon Night with Lunar CRater Observation and Sensing Satellite (LCROSS)." And observe the Moon we did! Over the course of the evening, about 60 people made their way to the top of the Hill in Inwood Hill Park. I only took up my six-inch Dobsonian, because it is infinitely easier to carry up those hills. The Moon was near full, and a crowd of about 25 was waiting to see our nearest celestial neighbor. Shoba Bindo Rao was there, giving her expertise on the sky. Rob Mahoney had a Galileoscope, a perfect thing to take to the top. Even with a slightly rickety tripod, he was able to get great views all night, including being able to see the bands of Jupiter. Rich Herrera had his four-inch refractor and was able to see quite a bit as well. Maya and Jordan brought up the binoculars, and Jordan refused to look through the Galileoscope since he wanted to build and look through his first. With his laminated lunar map, he helped teach people the wonders of the Moon. Fred, as always, introduced people to how to use telescopes. I chatted about the LCROSS mission to the interested crowd. Debates popped up as a result: "Why go back to the Moon?" "Water on the Moon?" "Won't the impactor cause something bad to happen here?" "How can you tell if water is there by hitting the Moon?" We had amazing views of the Moon. As the Moon, not at a great altitude for our location, dipped behind the trees, we were able to point out numerous double stars. But the Moon's glow and approaching clouds made clear it was not going to be a late night. Fortunately, they held off long enough for Jupiter to rise into view. Those late hangers-on got a great view of the moons, and the atmospheric structures on Jupiter. Th e dark patch was nowhere to be seen. I'd heard that the recent Jupiter impact should be visible if I stayed out late enough and watched pretty close. So on Monday the 3rd, I went out to try to take it in. My wife Donna and I ventured out to the baseball diamonds to see the rising Jupiter. I was immediately rewarded by the best seeing of the summer. The Moon, while low in the sky, made for a good target. I stayed until 4 a. m. My patience paid off in spades. Not only could I see Jupiter, but the Celestron 8" Nextstar SE coupled with a Meade 5000 UWA 8.8mm made it all jump out. The skies stayed amazingly steady. Io just touched Jupiter's limb. I could make out the disks of all four moons, as well as the 45 Cap in the field, ready to be occulted. I noticed the Great Red Spot was coming around the limb. I knew then that I wouldn't see the impact since it appears on the other side of the Great Red Spot. I saw Uranus as a bright blue disk and Mars as a red crescent. The stars of the Perseus double cluster leaped out, and I wished I had some AAVSO charts to take measurements. Neptune was a faint blue dot. Most interesting of the fuzzies was M31, the Andromeda Galaxy. As dawn approached and the Moon set, I noticed the nebulosity from M31 overwhelm the sky brightness. Nothing distinct, but you could tell it was there by just going off it a bit, and seeing the sky background change. I watched the Red Spot come around the limb and then across the meridian. I could easily see variations in the bands, and my young guest could see something that might have been smaller white oval storm features. I saw the kinks and secondary bands, as well as the boundary between the Red Spot and the band, and its central peak contrast. It was truly amazing to see such variation so clearly.

Whither the Light Bill?
A light-pollution bill that passed the State Assembly earlier this year was to have been heard by the State Senate Environmental Conservation Committee June 16, but that didn't happen because the Senate imploded due to party defections June 8. The staff of the bill's lead Senate sponsor, Antoine Thompson, is trying to get the bill (S2714) moved to the Senate Rules Committee to make it possible for Rules to bring the bill to the floor.

Contacting the AAA
If you want to join, volu n t eer , p a r t icip a t e in even t s, have a question or change your address, e-mail members @aaa.org, or leave a message at AAA hq: (212) 5352922. Also, visit us on the web at www.aaa.org.
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Levy Says Object that Hit Jupiter Was Likely a Comet
By Dan Harrison
The object that slammed in t o J u p it er t h is su m m er was probably a comet and not an asteroid, noted comet hunter David Levy told Ey epiece last month. Interviewed after giving two presentations nomical League convention in Hempstead, said the comet thesis made more sense since of dust over Jupiter's atmosphere was ident macher-Levy. at t N. the ical he AstroY., Levy behavior to Schu"I realized I might fail, but it might carry me through the forest of life. I might fail but I might learn. A teacher asked how I expected to make any money doing that, and said that if I hadn't discovered any comets in 25 years he would lower my grade. It took me 19 years, and I have now discovered 22." (Eclipsed continued from page 1)

Levy applauded the Australian amateur who first spotted evidence of an impact on Jupiter. However, he said beginners shouldn't be encouraged to do comethunting because NASA is so active in funding and discovering comets. "If you want to discover a comet and it's a do-or-die approach, don't do it. But if you're having fun with the sky, do it." In addition to keynoting the convention, Levy spoke at a session entitled "Is There a Future to Visual Comet Hunting?" After being introduced, he said no and sat down. But he then outlined h ow h e h u n t s for com et s. "I have six cameras running. I get up two hours before dawn and spend an hour setting up." Levy moves in a zig -zag pattern, down and up fields, generally north-south in the eastern sky. He alternates 16 fields per scope and 12 in a pair of binoculars. There are five camera-laden scopes. "During each lunation, I try to get as much of the sky before dawn as possible, he said. In July, Levy discovered Comet Christianson close to NGC 7331 in Pegasus. He knew it as a comet because it was a bit brighter than 7331 and had a tail. Levy, who heads t h e Na t ion a l Sh a r in g t h e Sk y Foundation, said his path in astronomy began at a meteor camp in 1956. "I put it in my brain, let it fester and it exploded four years later as the only thing I wanted to do. I did a doctoral thesis on the relationship of Shakespeare to astronomy--the night sky from 1572 to 1620, from Tycho's supernova to the invention of the scope.
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clouds loosening their grip on the Sun, only to have them close in again with renewed force before the best part of the eclipse. I'd seen many partial eclipses before. Now I've even been in the path of totality, traveling halfway around the world to get there, but I still haven't observed the fully eclipsed Sun and its remarkable phenomena-- the Diamond Ring, Baily's Beads, prominences and the delicate streamers of the solar corona, the Sun's rarified yet super-hot atmosphere. My trip to China was wonderful, but the eclipse wasn't among its finer moments. (Many people successfully viewed totality from Hangzhou.)
Yet having come so close (a n d so fa r ) in m y fir st attempt to view a total solar eclipse, I don't want to stop here. I'll try to be in the path of the 2017 solar eclipse, the first to cross the U.S. mainland since 1979. But I may not wait that long. I'm thinking of going to Australia for a 2012 eclipse. For the right opportunity I'm willing to see this rare, spectacular phenomenon. After the eclipse, I attended the International Workshop on Cometary Astronomy (IWCA IV) at the Shanghai Museum of Science and Technology. Generally held every five years, this year's conference, which stresses cooperation between amateurs and professionals in comet research, was split into two. IWCA V was held in Rio de Janiero in August. I gave a presentation in Shanghai on Tewfik, a comet observed only during a total solar eclipse in Egypt in 1882, and believed to have been a Kreutz sungrazer fragment similar to an exceptionally bright one seen in SOHO images in 2003. While at the conference, I met many Chinese amateurs I know from online astronomy projects, and who (Eclipsed continued on page 12)


Review: 44 Essays on the Development of Cosmology
By Shana Tribiano
In "Finding the Big Bang," edited by P. J. E. Peebles, L. A. Page Jr. and R. B. Partridge (Cambridge University Press, $72), the how and what of cosmology is delivered in 44 essays by contemporary scientists, with 47 cosmologists contributing in total. They portray their pursuits that brought about general agreement that the cosmic microwave background radiation (CMBR) implied a universe with a past that was described as a hot big bang. Debatably, it might not have been the case. The first few chapters provide background about the discovery. Committed to conveying the nature of early cosmological research, the authors comprehensively review the history of the field, acknowledging it's incomplete. That cosmology was revealed t o b e a t est a b le p u r suit at all, in the last century, was remarkable in itself. Around 1950, major momentum towards a consistent interpretation developed. Agreement that the bath of light that permeates all space, the CMBR, is a fossil from a hot past of about 13 billion years ago grew. Measurements of the CMBR, whose temperature today, 3 K, corresponds to the microwave portion of the electromagnetic spectrum, gradually distinguished between possible universes that had been hypothesized. The CMBR effectively ignited what we pursue in trying to understand about the cosmos today. As you can imagine, the book's essays are technical. There is no informal conversation about megaparsecs and thermal equilibrium. But it's not like a bad textbook in any way. Velocity is succinctly and clearly explained without equations or numbers. In this way, the book can be home to a variety of readers. Although it leans heavily towards numerical detail compared to a non-textbook book, it feels like a biography. Undergraduates will likely en j oy t h e foot n ot es. An undergraduate physics, astronomy, astrophysics, or even engineering or math major will enjoy the footnotes more. There's even nice calculus-level homework suggested. Digging back to early last century, the essayists describe the cards on the table then. They cite competing theories that reflected the data of the day. Some descriptions depended on a hot Big Bang theory and others, like the steady state, static universe model or cold big bangs, didn't. The writers show how the CMBR sorted things out. The fifth and last chapter is r eflect ive, b egin n in g with reference to the CMBR as one among a list of cosmological cornerstones. After the last chapter, the appendix provides material that seems like great character sketches in the form of CBR experiment profiles, tabulated by frequency, corresponding temperature and experiment name. Chapter 4 begins the personal essays, which give the book its flavor. Some recollections are short, some long. They all act as very direct windows into the past. They reflect on many aspects of the field, from personal experiences to pressing arguments and counterpoints. A noticeable characteristic of the essays is an intimacy in the endeavor. Confessions of the authors' missed opportunities and leading others astray are endearing. Some recollections recount predictions writers made that turned out to be true but were never published. The essays reveal h ow con ver sa t ion a l p r ogr ess is. They span a great network of people across continents. The collection is at least as much about people and how they collaborate as it is about the history of the great cosmic discovery that's the Big Bang model. The recollections are full of interesting facts, concepts and developments: researchers correcting their own results, incrementally adding new pieces to a multifaceted puzzle. The puzzle pieces are described well. Some can easily be put in the pockets of your memory. Others take more time to enjoy, like the detail in predictions that didn't match the data. Not frequent, but quite noticeable, are descriptions of feelings upon scientific realization. However brief, they are distinct, just as each essay is distinct.
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Briefs: Two Planets Smashed Into Each Other
Two planets orbiting a you n g st a r a p p a r en t ly smashed into each other at high speeds thousands of years ago. Plumes of vaporized rock and lava from the collision revealed their existence to Spitzer. The pileup occurred within the last few thousand years. The smaller of the planets--about the size of the Moon, according to computer models--was apparently destroyed by the crash. The other was likely a Mercury-sized-planet and survived, albeit severely dented. The planets were believed moving at 22,400 mph before the crash. The wreck released amorphous silica rock, or melted glass, and hardened chunks of lava. Spitzer also spotted large clouds of orbiting silicon monoxide gas created when the rock was vaporized. Infrared detectors found traces of rocky rubble and refrozen lava around a young star, HD 172555, in early stages of planet formation. The system, some 100 light-years away, is 12 million years old. A newfound planet orbits b a ck wa r d com p a r ed t o the rotation of its star. A near-collision may have created the retrograde orbit. The star and its planet, WASP-17, are about 1,000 light-years away. WASP-17 likely had an encounter with a larger planet, and the gravitational interaction put WASP-17 on its odd course. WASP-17 is half the mass of Jupiter but bloated to twice its size. The bloated planet can be explained by a highly elliptical orbit, which brings it close to the star and then far away. Some comets headed t o E a r t h 's neighborhood from outer reaches of the solar system likely follow a different route than thought, new modeling suggests. Comets from this region should rarely cross Earth's orbit, so aren't a collision concern. In turn, these rare encounters mean these comets are unlikely to have caused past mass extinctions. Long-period comets--with highly elongated orbits that take them hundreds or thousands of years to circle the Sun--were long thought to come from the outer region of the Oort Cloud. Astronomers found comets from the inner Oort Cloud could slip past the protective barrier of Jupiter and Saturn and reach an Earth-crossing orbit. New modeling suggests a substantial portion of observable long-period comets actually come from the inner, not the outer, Oort Cloud. An estimate of the comets likely to have struck Earth during the last 500 million years is no more than two or three.
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ered in a comet sample, supporting the idea that such icy objects seeded early Earth with material needed for living organisms. New research firms up past suggestions of glycine, the simplest amino acid used to make proteins, inside samples from Comet Wild 2. This is the first time an amino acid has been found in a comet. Discovery of glycine in a comet supports the idea that building blocks of life are prevalent in space, and backs the argument that life in the universe may be common, not rare. Glycine molecules from space tend to have heavier Carbon 13 atoms