=========================================================================<br /><br /> * * * * SKY & TELESCOPE's WEEKLY NEWS BULLETIN - May 17, 2002 * * * *<br /><br />=========================================================================<br />Welcome to S&T's Weekly News Bulletin. Images, the full text of stories<br />abridged here, and other enhancements are available on our Web site,<br />SkyandTelescope.com, at the URLs provided below. Clear skies!<br />=========================================================================<br /><br />11 MORE NEW MOONS FOR JUPITER<br /><br />Scott S. Sheppard and David C. Jewitt (University of Hawaii) announced<br />yesterday the discovery of 11 new moons around Jupiter. With the finding,<br />Jupiter now has 39 confirmed satellites....<br /><br />Jupiter's newest moons are all no more than 2 to 4 kilometers across<br />(assuming their surfaces are very dark), and they all have retrograde<br />(backward) orbits. Each has a period between 557 and 773 days....<br /><br />>
http://SkyandTelescope.com/news/current/article_604_1.asp<br /><br />------------------------------------------------------------------------<br /><br />UNIQUE CRATER SWARM DISPUTED<br /><br />A controversy is brewing over the origin of several unusual depressions in<br />the Pampean plain of northern Argentina. For the last decade planetary<br />scientists have considered a cluster of large, elongated pits near Rio<br />Cuarto to be unique impact craters, gouged by a chunk of asteroid that<br />glanced obliquely through the atmosphere and broke into pieces just before<br />striking the Earth....<br /><br />The impact hypothesis recently received its most serious challenge from a<br />team led by Phil A. Bland (Open University, London). In the May 10th issue<br />of Science, they detail a pair of meteorites found within the putative<br />craters that not only have different makeups but also appear to have<br />arrived on Earth 36,000 and 52,000 years ago -- far longer than the age of<br />the depressions in which they were found. Bland's team also contends that<br />the strange depressions, up to 4.5 kilometers long and 1 km wide, look<br />much like hundreds of other smaller features scattered throughout the<br />region -- a situation far too unlikely to be caused by a single<br />collisional event.<br /><br />This would suggest that the Rio Cuarto craters are not craters at all but<br />rather long hollows carved and shaped over thousands of years by<br />prevailing winds. In the process, the gradual removal of material exhumed<br />meteorites that had fallen to Earth long ago. "I'd love them to be<br />low-angle impacts," Bland told Sky & Telescope, "but I just don't think<br />the evidence is there...."<br /><br />>
http://SkyandTelescope.com/news/current/article_602_1.asp<br /><br />------------------------------------------------------------------------<br /><br />MISSING PLANETARY INGREDIENT FOUND<br /><br />Astronomers know how much sulfur should be in protoplanetary disks, the<br />places where planets are forming around other stars. Meteorites -- relics<br />from the earliest epochs of our own solar system -- provide the evidence.<br />Scientists can take a meteorite into a lab and learn exactly what the rock<br />is made of and how much of each element it contains.<br /><br />But observations of protoplanetary disks were confusing at best. If<br />meteorites indeed tell us the ingredients of the early solar system, then<br />their composition should match spectroscopic observations of disks. Yet<br />sulfur appeared to be missing. In a study published in last week's Nature,<br />a team of researchers led by Lindsay P. Keller have apparently solved the<br />mystery....<br /><br />Keller's team identified iron sulfide (FeS) to have a broad absorption<br />feature at 23.5 microns. Previous researchers had attributed the 23-micron<br />line in space to FeO, not FeS. The "new" abundances of observed sulfur are<br />consistent with theoretical estimates, assuming that most of the sulfur<br />resides in FeS grains....<br /><br />>
http://SkyandTelescope.com/news/current/article_601_1.asp<br /><br />------------------------------------------------------------------------<br /><br />ASTRO NEWS BRIEFS<br /><br />Earth's Space Heat Shield<br /><br />Earth's magnetic field protects us from much of the life-threatening<br />radiation that comes our way. However, while it deflects most of the<br />Earthbound high-energy particles streaming from the Sun, it doesn't do all<br />the work. As recent data from NASA's Imager for Magnetopause to Aurora<br />Global Exploration (IMAGE) spacecraft reveals, our outer atmosphere picks<br />up the slack. In a pair of articles to appear in the Journal of<br />Geophysical Research, scientists report that Earth's outer ionosphere --<br />between 300 to 1,000 kilometers (180 and 620 miles) above the surface --<br />absorbs energy from the solar wind, heats up to a billion degrees, and<br />casts away the excess energy as charged particles that fly off into space.<br />A few hundred tons of the ionosphere is lost during a during a typical<br />space storm. The resulting very thin cloud of incredibly hot plasma, they<br />note, can affect orbiting satellites.<br /><br />Astro Award Winners Announced<br /><br />Each year, the Astronomical Society of the Pacific recognizes the research<br />and educational service of several professional and amateur astronomers.<br />The winners for 2002 are:<br /><br />The Catherine Wolfe Bruce Gold Medal -- Bohdan Paczynski (Princeton<br />University)<br />The Klumpke-Roberts Award -- astronomical artists Don Davis and Jon<br />Lomberg<br />The Maria and Eric Muhlmann Award -- François Roddier (University of<br />Hawaii)<br />The Thomas J. Brennan Award -- Philip M. Sadler (Harvard-Smithsonian<br />Center for Astrophysics)<br />The Robert J. Trumpler Award -- Volker Bromm (Harvard-Smithsonian Center<br />for Astrophysics)<br />The Las Cumbres Amateur Outreach Award -- Arizona amateur Dean Ketelsen<br /><br />Searching to Understand the Dark Universe<br /><br />Canadian and French astronomers will be teaming up to investigate "dark<br />matter," which is believed to make up 90 percent of the mass of the<br />universe, and "dark energy," which is believed to pervade space causing it<br />to expand at an ever-growing rate. Astronomers will spend five years using<br />the 3.6-meter Canada-France-Hawaii Telescope atop Mauna Kea to survey the<br />sky using MegaCam, the world's largest astronomical camera. It can snap an<br />image 1° square, four times the size of the full Moon. The 2,000 images of<br />the CFHT Legacy Survey will be used to identify the source of dark energy,<br />map the distribution of dark matter, and also look for Kuiper Belt objects<br />in the far reaches of the solar system.<br /><br />>
http://SkyandTelescope.com/news/current/article_605_1.asp<br /><br />------------------------------------------------------------------------<br /><br />HIGHLIGHTS OF THIS WEEK'S SKY<br /><br />* First quarter Moon on May 19th.<br />* Venus is brilliant in the west-northwest at twilight. It shines at<br />magnitude -4.0.<br />* Saturn is disappearing deep into the sunset.<br />* Uranus and Neptune (magnitudes 6 and 8, respectively, in or near<br />Capricornus) are in the southeast before dawn.<br /><br />For details, see This Week's Sky at a Glance and Planet Roundup:<br /><br />>
http://SkyandTelescope.com/observing/ataglance/<br /><br />------------------------------------------------------------------------<br /><br />Copyright 2002 Sky Publishing Corp. S&T's Weekly News Bulletin is provided<br />as a free service to the astronomical community by the editors of SKY &<br />TELESCOPE magazine. Widespread electronic distribution is encouraged as<br />long as our copyright notice is included, along with the words "used by<br />permission." But this bulletin may not be published in any other form<br />without written permission from Sky Publishing; send e-mail to<br />permissions@SkyandTelescope.com or call +1 617-864-7360. More astronomy<br />news is available on our Web site at
http://SkyandTelescope.com/news/.<br /><br />------------------------------------------------------------------------
