Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.astrolib.ru/rsn/1998/12/22/
Дата изменения: Unknown
Дата индексирования: Sat Apr 9 23:35:52 2016
Кодировка: Windows-1251
Поисковые слова: п п п п п п п п п п п п п п п п п п
Электронная библиотека астронома-любителя. RU.SPACE.NEWS - архив за 22 декабря 1998.
Электронная библиотека астронома-любителя. Книги по астрономии, телескопостроению, оптике.


Ru.Space.News:
Декабрь 1998
ПнВтСрЧтПтСбВс
 
123456
78910111213
14151617181920
21222324252627
28293031
 

год:



  • Обзоры оружия и снаряжения
  • m31.spb.ru


    • AstroTop-100

    Яндекс цитирования


    0.036
    YouTUBE NauchFilm Channel

    Архив RU.SPACE.NEWS за 22 декабря 1998

    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: O'Neil Named Manager Of 2003, 2005 Mars Sample Return Missions Привет всем! Вот, свалилось из Internet... MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov Contact: Diane Ainsworth FOR IMMEDIATE RELEASE December 17, 1998 O'NEIL NAMED MANAGER OF 2003, 2005 MARS SAMPLE RETURN MISSIONS William J. O'Neil, who served as project manager of NASA's Galileo mission to Jupiter at the Jet Propulsion Laboratory, Pasadena, CA from 1990 to 1998, has been named manager of the agency's first two Mars sample return missions, scheduled for launches in 2003 and 2005. O'Neil, who was appointed in mid-November, had served as the chief technologist for the Mars exploration program in the interim, overseeing all aspects of technology development and implementation for NASA's long-range program of robotic exploration of Mars. This summer he led a comprehensive effort at JPL to redesign the architecture of the Mars sample return missions to determine the best approach for these first-ever missions. Prior to his appointment as Galileo project manager, he served as the Galileo science and mission design manager during the spacecraft's development phase. The Galileo spacecraft is continuing its extended science mission to study Jupiter's major moons, atmosphere and magnetosphere. Galileo became the first spacecraft to orbit an outer planet and penetrate its atmosphere. On its circuitous route to Jupiter, the spacecraft also became the first to perform close-up asteroid studies when it flew past the asteroids Gaspra and Ida. O'Neil's past assignments have included work, in the mid- 1960s, as a trajectory design and navigation engineer for the Lunar Surveyor project, which became the first robotic spacecraft to soft-land on the surface of the moon. He also served as navigation chief on the 1971 Mariner mission to Mars, the first U.S. spacecraft to orbit another planet, and navigation chief for the Viking mission to perform the first soft-landings on the surface of Mars. Before joining JPL in 1963, O'Neil was as an aerospace engineer working in 1960 at the Boeing Airplane Company in Renton, Washington. From 1961 to 1963, he was an employee of Lockheed Missiles and Space Company in Sunnyvale, CA. O'Neil earned his bachelor of science degree with distinction in aeronautical engineering in 1961 from Purdue University, West Lafayette, Indiana, and his master of science degree in aerospace engineering in 1967 from the University of Southern California. O'Neil is the recipient of NASA's highest award, the Distinguished Service Medal, and Purdue University's Distinguished Alumni Award. He also holds an honorary doctorate from the University of Padova, Italy, home of the Galileo spacecraft's namesake, 16th century astronomer Galileo Galilei. O'Neil resides with his wife in Sierra Madre, CA, and has three adult children. Hа сегодня все, пока! =SANA=
    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: Cassini Update - December 18, 1998 Привет всем! Вот, свалилось из Internet... Cassini Significant Events for 12/11/98 - 12/17/98 Spacecraft Status: The most recent spacecraft status is from the DSN tracking pass on Thursday, 12/17, over the Goldstone tracking station. The Cassini spacecraft is in an excellent state of health and is executing the Cruise 11 sequence normally. The Cassini spacecraft is presently traveling at a speed of approximately 66,338 kilometers/hour relative to the sun and has traveled approximately 1.079 billion kilometers since launch on October 15, 1997. Spacecraft Activity Summary: On Friday, 12/11, the Solid State Recorder (SSR-B) record and playback pointers were reset as planned. On Sunday, 12/13, two planned of the three possible components of Periodic Engineering Maintenance were performed. All activities were nominal;the third component is planned for next week. On Wednesday, 12/16, routine maintenance was performed on the Solid State Recorder (SSR-B) flight software partitions. On Thursday, 12/17, an Instrument Flight Software update was performed for MIMI in preparation for Instrument Checkout. Upcoming events: Activities scheduled for the week of 12/18-12/24 include SSR Pointer Reset, Periodic Engineering Maintenance (Reaction Wheel Portion), and Instrument Flight Software update for CDA, CIRS and RPWS on 12/18, Probe Checkout, SSR Pointer Resets, and Flight Software update for CAPS and INMS on 12/21, and reset of the PSA (Probe Support Avionics) Prime status following Probe Checkout on 12/22. Cassini Outreach Jet Propulsion Laboratory California Institute of Technology National Aeronautics and Space Administration Pasadena, Calif. 91109. Telephone (818) 354-5011 Hа сегодня все, пока! =SANA=
    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: NEAR Update - December 18, 1998 Привет всем! Вот, свалилось из Internet... NEAR Mission Status Reports - http://near.jhuapl.edu NEAR WEEKLY REPORT December 18, 1998 MISSION OPERATIONS: All systems are "GO" for Rendezvous Burn 1 on 12/20/98 at 5:00 p.m. EST. The NEAR spacecraft state/configuration has remained nominal (Flight Computer#1 and Attitude Interface Unit #1 active) throughout this reporting period. The MSI, MAG, NIS, and XGRS instruments have remained on during this reporting period. The NLR will remain off until 1/21/99. All activities planned for this period were successfully conducted including: Daily repeating Eros Optical Navigation Images NIS SDC Test 1 NIS SDC Test 2 MSI/NIS Eros Mono Light curve 3 Preparations for the upcoming rendezvous burn this Sunday (12/20) continue on schedule. All commands for Rendezvous Burn 1, and Contingency Burn 1A, are loaded on the spacecraft and enabled. A short test pressurization of the propulsion system will execute today at 2:00 p.m. EST, followed 4 hours later by a longer pressurization test. A change to the mission timeline to turn off the MAG, XGRS, and NIS instruments from 12/19 through 12/30 has been made to provide additional power margin for the upcoming rendezvous burns. 24 hour/day monitoring of the spacecraft has begun. This will continue for the next two months. All science and engineering data was recovered from the spacecraft for this reporting period. Upcoming Spacecraft Activities: December 19: XGRS, MAG, NIS OFF December 20: Rendezvous Burn 1- 5:00 p.m. EST December 21: OpNav B, repeated every 8 hours until Rendezvous Burn 4 December 23: MSI/NIS Mono Light Curve 4 December 23: MSI/NIS Mono Light Curve 5 December 27: Eros Satellite Search A December 28: Rendezvous Burn 2 December 29: Rendezvous Burn 3 (optional cleanup burn) December 30: XGRS, MAG, NIS ON Debra Fletcher The Johns Hopkins University Applied Physics Laboratory Bldg.-Rm.: 2-155 11100 Johns Hopkins Road Laurel, MD 20723-6099 240-228-8274/Washington 443-778-8274/Baltimore Fax: 240-228-3237 Email: debra.fletcher@jhuapl.edu Hа сегодня все, пока! =SANA=
    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: Sky & Telescope News Bulletin - December 18, 1998 Привет всем! Вот, свалилось из Internet... SKY & TELESCOPE'S NEWS BULLETIN DECEMBER 18, 1998 COSMOLOGICAL TOP STORY OF THE YEAR The discovery that the expansion of the universe is actually accelerating has been named the 1998 "Breakthrough of the Year" by the journal *Science.* As described by Ann K. Finkbeiner in the September issue of *Sky & Telescope* (page 38), astronomers with the Supernova Cosmology Project and the High-Z Supernova Search Team unexpectedly found that the universe seems to be accelerating, as if driven by some kind of "antigravity" force (termed the cosmological constant). Additional analysis continues to support this idea. Virginia Trimble summarizes this and other significant astronomical findings from the past year in the February issue of *Sky & Telescope,* now in the mail to subscribers. GEMINID RECAP Normally one of the year's most rewarding and dependable meteor showers, the Geminids are often likened to August's popular Perseid shower. The 1998 Geminids, however, were destined to be measured against November's Leonid fireball show. Initial accounts suggest the Geminids gave a solid performance. This year's Geminids favored observers in Hawaii, where the radiant was high overhead during the peak on the 14th. Observing from the Big Island, Jaimie and Bill Perry lost count at 100 per hour as meteors began to arrive at a rate of one every two to three seconds and streaked all over the sky. Meanwhile in Volcano, Hawaii, *Sky & Telescope* contributing editor Stephen James O'Meara monitored the display through holes in a persistent cloud cover but still managed to see 44 meteors in one hour. The Geminids share another trait with the Leonids: future levels of activity are difficult to predict. Next year's Geminid display might prove even richer as the shower's parent asteroid 3200 Phaethon swings within 1.2 astronomical units of Earth on October 16th. A SPACECRAFT BONANZA All systems are well a week after the December 11th launch of Mars Climate Orbiter. Flight controllers will command the spacecraft to make its first -- and largest -- trajectory correction maneuver on Monday, December 21st. This will direct the craft for an on-time arrival at Mars in September 1999. Shortly afterward, the probe's two scientific instruments will be checked out. Engineers continue to calibrate the instruments aboard NASA's Submillimeter Wave Astronomy Satellite (SWAS), launched on December 5th. SWAS will study the composition of interstellar matter at a wavelength that cannot be examined from Earth's surface. All things are go with Deep Space 1. After a two-week run using its ion-propulsion drive, the engine was turned off so that two instruments -- a plasma experiment and spectrometer -- could be checked out. Engineers then tested to see how high the drive could be set before the spacecraft could no longer run the engine with only solar power and began drawing from its battery. And finally, the Near Earth Asteroid Rendezvous (NEAR) spacecraft is now only three weeks away from its historic encounter with asteroid 433 Eros. NEAR will be the first spacecraft to go into orbit around a minor planet on January 10th. On December 20th, NEAR will be commanded to make the first of three planned trajectory corrections to cozy the spacecraft up to the 32-by-13-kilometer asteroid. SUN TO MOVE NORTH The solstice occurs at 8:56 p.m. EST Monday, December 21st. This is when the Sun is at its farthest south for the year and begins its six-month return north. In the Northern Hemisphere, winter begins and we get the year's longest night. In the Southern Hemisphere, summer begins with the year's longest day. THIS WEEK'S "SKY AT A GLANCE" Some daily events in the changing sky, from the editors of SKY & TELESCOPE. DEC. 20 -- SUNDAY * The waxing crescent Moon stands well to the upper left of Venus, low in the southwestern sky at dusk. * Some doorstep astronomy: Look low in the east-southeast in early evening for the bright constellation Orion. It rises higher in the southeast later in the night. In its middle you'll see a nearly vertical row of three stars, Orion's Belt. The Belt points upward roughly to the orange star Aldebaran (look about two fist-widths at arm's length above the Belt). Higher above Aldebaran and a bit right is the little Pleiades star cluster, the size of your fingertip at arm's length. * Mercury is at greatest elongation, shining low in the dawn 22 degrees from the Sun. DEC. 21 -- MONDAY * The solstice occurs at 8:56 p.m. EST. This is when the Sun is at its farthest south for the year and begins its six-month return north. In the Northern Hemisphere, winter begins and we get the year's longest night. In the Southern Hemisphere, summer begins with the year's longest day. * Early this evening the faint asteroid 245 Vera should occult (cover) a 9th-magnitude star near the Taurus-Gemini border for observers along a narrow track from Lake Superior through Utah. The occultation, which could last up to 8 seconds, should come within a few minutes of 6:59 p.m. Central Standard Time, 5:59 p.m. Mountain Standard Time. Finder charts for this week's asteroid occultations are in the December Sky & Telescope, page 124, and at http://www.skypub.com/sights/occultations/occultations.html. * Seen in a medium-sized telescope, Jupiter's Great Red Spot should cross Jupiter's central meridian (the imaginary line down the center of Jupiter's disk from pole to pole) around 10:26 p.m. Eastern Standard Time. Lately the spot has been very pale tan. For a list of all predicted Red Spot transit times, see http://www.skypub.com/sights/moonplanets/redspot.html. * The eclipsing variable star Algol should be in one of its periodic dimmings, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 11:50 p.m. EST. Algol takes several additional hours to fade and brighten. For all its predicted minima see http://www.skypub.com/sights/variables/algol.html. DEC. 22 -- TUESDAY * Antares is 6 degrees south (lower right) of Mercury Wednesday morning; look low in the southeast during early dawn. Binoculars will help. DEC. 23 -- WEDNESDAY * The faint asteroid 49 Pales should occult a 9.5-magnitude star in Aquarius for observers in parts of the Southeast. The occultation, which could last up to 5 seconds, should take place around 7:07 p.m. EST. See http://www.skypub.com/sights/occultations/occultations.html. DEC. 24 -- THURSDAY * Jupiter is the "star" shining to the upper left of the Moon this evening. * Jupiter's Red Spot transits around 7:56 p.m. EST. * Algol should be at minimum light for a couple hours centered on 8:39 p.m. EST. DEC. 25 -- FRIDAY * Jupiter shines to the right of the Moon at dusk, and to the Moon's lower right later in the evening. DEC. 26 -- SATURDAY * First-quarter Moon (exact at 5:46 a.m. EST). * Jupiter's Red Spot should transit around 9:35 p.m. EST. THIS WEEK'S PLANET ROUNDUP MERCURY appears low in the southeast during dawn. Look for the dimmer star Antares to its lower right early in the week and more directly to its right later in the week. VENUS is very low in the southwest during early dusk. Look about 30 minutes after sunset. MARS, shining at magnitude +1.2 in Virgo, rises around 1 a.m. and is high in the south by dawn. Spica is the star below it or to its lower left. JUPITER, magnitude -2.4, is the big, bright "star" high in the south at dusk. It gets lower in the southwest later in the evening and sets around 11 p.m. SATURN, magnitude +0.2, is the yellowish "star" far to Jupiter's left at dusk and to Jupiter's upper left later in the evening. The two planets appear 36 degrees apart (about 4 fist-widths at arm's length), on opposite ends of Pisces. URANUS, NEPTUNE, and PLUTO are hidden behind the glare of the Sun. (All descriptions that relate to the horizon or zenith are written for the world's midnorthern latitudes. Descriptions that also depend on longitude are for North America. Eastern Standard Time, EST, equals Universal Time minus 5 hours.) More details, sky maps, and news of other celestial events appear each month in SKY & TELESCOPE, the essential magazine of astronomy. See our enormous Web site at http://www.skypub.com/. Clear skies! SKY & TELESCOPE, P.O. Box 9111, Belmont, MA 02478 * 617-864-7360 (voice) Copyright 1998 Sky Publishing Corporation. S&T's Weekly News Bulletin and Sky at a Glance stargazing calendar are provided as a service to the astronomical community by the editors of SKY & TELESCOPE magazine. Widespread electronic distribution is encouraged as long as these paragraphs are included. But the text of the bulletin and calendar may not be published in any other form without permission from Sky Publishing (contact permissions@skypub.com or phone 617-864-7360). For updates of astronomical news, including active links to related Internet resources, are available via SKY & TELESCOPE's site on the World Wide Web at http://www.skypub.com/. In response to numerous requests, and in cooperation with the Astronomical League (http://www.mcs.net/~bstevens/al/) and the American Association of Amateur Astronomers (http://www.corvus.com/), S&T's Weekly News Bulletin and Sky at a Glance are available via electronic mailing list too. For a free subscription, send e-mail to skyline@corvus.com and put the word "join" on the first line of the body of the message. To unsubscribe, send e-mail to skyline@corvus.com and put the word "unjoin" on the first line of the body of the message. SKY & TELESCOPE, the Essential Magazine of Astronomy, is read by more than 200,000 enthusiasts each month. It is available on newsstands worldwide. For subscription information, or for a free copy of our catalog of fine astronomy books and products, please contact Sky Publishing Corp., 49 Bay State Rd., Cambridge, MA 02138-1200, U.S.A. Phone: 800-253-0245 (U.S. and Canada); 617-864-7360 (International). Fax: 617-864-6117. E-mail: custserv@skypub.com. WWW: http://www.skypub.com/. Clear skies! Hа сегодня все, пока! =SANA=
    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: National Science Foundation Telescope Sheds Light On Fate Of Universe Привет всем! Вот, свалилось из Internet... National Science Foundation Washington, D.C. Media contacts: Peter West (703) 306-1070 pwest@nsf.gov Teresa Thomas (412) 268-3580 ts2h+@andrew.cmu.edu Embargoed until 7 A.M. EDT, December 18, 1998 NSF PR 98-88 NSF Telescope Sheds Light On Fate Of Universe Researchers from Carnegie Mellon University, using a National Science Foundation (NSF) microwave telescope in Antarctica, have made a crucial measurement of cosmic background radiation that may help science to settle a fundamental question of whether the universe will expand forever or collapse back upon itself. Scientists measured the dimensions of extremely distant gas clouds with the Viper Telescope, operated by the Center for Astrophysical Research (CARA) in Antarctica at NSF's Amundsen-Scott South Pole Station. Jeffrey Peterson, a Carnegie Mellon astrophysicist and the lead scientist on the Viper project, announced the findings on Dec. 18 in Paris, France at the Symposium on Relativistic Astrophysics. The biennial meeting attracts the world's foremost astronomers and astrophysicists. "These findings indicate that the material of the universe was given just the right kick by the Big Bang to expand forever, never collapsing, but also never becoming so dilute that gravity can be ignored," according to Peterson. "This delicate balance is hard to understand unless inflation theory, or something akin to it, is correct." Viper is used to make images of the faint structure, an anisotropy, seen in the sky. Astrophysicists widely accept that if the expansion of the universe were slowing, the glowing clouds of gas observed with Viper would be, in astronomical terms, relatively close by and would measure as much as one-half degree of arc across the sky. The discovery announced this week -- that the size of extremely distant gas clouds is, indeed, one-half degree on the sky indicates that the expansion of the universe is slowing at just the rate predicted by inflation theory. Inflation theory holds that just after the Big Bang, as the universe expanded and cooled, it passed through a critical temperature, currently thought to be 100 billion degrees -- which changed the character of the laws of physics. As the proto-universe passed through this critical temperature threshold, there was an enormous release of energy, which caused the universe to "inflate,' or to dramatically increase in size. This inflation process would have caused the universe to expand with a precise "escape velocity," which would provide an explanation for the Viper findings. The newly released easurements indicate that the universe has just such an escape velocity, Peterson stressed. The anisotropy measurement is just a small part of the data collected from the telescope, which provides a snapshot of the universe as it was 300,000 years after the Big Bang, the cataclysmic event that set in motion the forces that created today's universe. Previous cosmic background telescopes have been smaller than Viper and have not been able to focus in fine enough detail to measure the clouds as viper can. However, the CARA group's work with these earlier prototypes was critical to the new discovery. Karl Erb, the director of NSF's Office of Polar Programs, said "This advance is a fitting testament to the vision and dedication of the CARA scientists whose pioneering work proved that the South Pole is an ideal site for these delicate measurements." The two-meter Viper telescope began operation only last February. Further observations by Viper and other telescopes under development by CARA's member institutions are planned to verify the newly released result. Andrew Yee ayee@nova.astro.utoronto.ca Hа сегодня все, пока! =SANA=
    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: A New Earth Observation Satellite for Canada (Forwarded) Привет всем! Вот, свалилось из Internet... Canadian Space Agency St. Hubert, Quebec A New Earth Observation Satellite for Canada -- Government of Canada Successfully Negotiates RADARSAT-2 Agreement With MacDonald Dettwiler VANCOUVER, BRITISH COLUMBIA, December 18, 1998 -- John Manley, Industry Minister and Minister responsible for the Canadian Space Agency (CSA), announced today the conclusion of successful negotiations with MacDonald Dettwiler (MDA) of Richmond, B.C., to construct and operate a $305 million satellite system, RADARSAT-2. It is expected that approximately 300 jobs will be created during the three-year construction phase of the project. MDA's estimates also indicate that the total number of jobs created will be approximately 3,500 person-years over what is expected to be a seven-year project. "This project will result in the construction of the world's most advanced Earth observation satellite, scheduled to be launched in November 2001," said Minister Manley. "RADARSAT-2 is concrete proof of Canada's commitment to a vigorous knowledge-based economy through the establishment of public-private sector partnerships," he added. "High-technology projects like this one will lead our entry in the next millennium, creating jobs tailored to the new economy. In fact, this is the largest space contract ever awarded in British Columbia," he concluded. RADARSAT-2 is the outcome of a ground-breaking financial and management arrangement. Under the terms of the agreement, the Government of Canada and MacDonald Dettwiler will invest $225 million and $80 million respectively for the construction of this satellite system. CSA's contribution to the system is considered a pre-payment for future government data requirements. The government will recuperate its financial input through the provision of RADARSAT-2 imaging data of equivalent value. MacDonald Dettwiler will be responsible for all ongoing operations and data commercialization. "MacDonald Dettwiler is very proud to be the chosen industry partner of the Canadian Space Agency in building RADARSAT-2," said MacDonald Dettwiler CEO, Dan Friedmann. "This agreement heralds a new era in the field of Canadian remote sensing. It enables MacDonald Dettwiler to lead Canada into the competitive worldwide Earth observation market and into developing a significant value- added information industry." The RADARSAT satellites are unlike most remote sensing satellites in that they are able to collect images through the use of a powerful radar which provides all-climate, all weather conditions imagery of the Earth to clients. RADARSAT-2's innovations will build on the successes of RADARSAT-1 and offer improved quality of data images to meet the growing world demand for Earth observation information. These images have proven to be effective tools in the management and monitoring of the global environment in areas of ice navigation, cartography, geological exploration, maritime surveillance, disaster relief operations, agriculture and forestry surveillance. Having captured much of the world's market in Earth observation, MacDonald Dettwiler has set out to build a major company, capable of delivering a broad range of information products about the Earth to customers around the world. MacDonald Dettwiler's mandate is to deliver the information and systems required to monitor the scope of human activities on our planet. The Canadian Space Agency is committed to leading the development and application of space knowledge for the benefit of Canadians and humanity. -30- FOR FURTHER INFORMATION PLEASE CONTACT: Canadian Space Agency Stephane Corbin Manager, Media and Public Relations (450) 926-4350 cell:(514) 917-9509 stephane.corbin@space.gc.ca http://www.space.gc.ca or MacDonald Dettwiler Michael Harding Director of Public Relations (604) 231-2262 mharding@mda.ca http://www.mda.ca or Jennifer Sloan Press Secretary, Office of the Minister of Industry (613) 995-9001 Andrew Yee ayee@nova.astro.utoronto.ca Hа сегодня все, пока! =SANA=
    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: Astronomers examine brown dwarf's hazy atmosphere (Forwarded) Привет всем! Вот, свалилось из Internet... New Mexico State University Las Cruces, New Mexico December 15, 1998 Astronomers examine brown dwarf's hazy atmosphere By Karl Hill Brown dwarfs, sometimes known as failed stars, have a reputation for being the dim bulbs of the heavens. That's one reason the first real specimen, a brown dwarf named Gliese 229B, was discovered only three years ago. But Gliese 229B presented a puzzle to New Mexico State University astronomer Mark Marley and his colleagues as they studied the strange new object, because it seemed even darker than expected. "Brown dwarfs are supposed to be dim, but it was turning out to be much, much darker than we would have thought in the optical part of the spectrum," Marley said. In a classic example of the high-tech detective work today's astronomers use to analyze distant objects, Marley and two colleagues have determined that the brown dwarf suffers from a malady similar to one Los Angeles is famous for -- a hazy atmosphere. "The compounds are different, but it's like the red haze you see when you fly into Los Angeles," he said. While L.A.'s smog is caused by sunlight reacting with auto emissions and other particles in the air over the city, the brown dwarf's red haze is thought to be caused by a different sort of chemical reaction. It appears that gases in the brown dwarf's atmosphere, primarily methane, react with light from a nearby star that Gl229B orbits, causing them to form more complicated molecules that clump together to form extremely small drops, Marley said -- drops about one-hundredth the size of those that form clouds in the Earth's atmosphere. The drops tend to block the visible light from the brown dwarf but are transparent in other parts of the spectrum, he said. Results of the analysis of Gl229B's atmosphere were published in the Dec. 11 issue of Science, the weekly journal of the American Association for the Advancement of Science. The article was written by Caitlin Griffith of Northern Arizona University's Department of Physics and Astronomy, Roger Yelle of Boston University's Center for Space Physics, and Marley, a planetary scientist in NMSU's Department of Astronomy. Solving this particular mystery about this particular brown dwarf, Marley said, adds to scientists' understanding of the universe around us. Since Gliese 229B was discovered, by a team of Cal Tech and Johns Hopkins scientists, "there are now dozens of brown dwarfs that have been discovered, and it's important to understand what their spectra can tell us about them," Marley said. "If these guys turn out to be a common part of the universe, we have to get a basic understanding of what's going on in their atmospheres, how hot they are, what they're made of." Brown dwarfs are too small and cool to be stars and too massive to be planets. Scientists believe they form the same way stars do, but never accumulate enough mass to sustain nuclear fusion at their cores. They seem to share some characteristics with giant planets like Jupiter. Drawing on his research on Jupiter and other planets, Marley has developed computer models that help astronomers examine newly discovered objects such as brown dwarfs and planets orbiting stars beyond our solar system. His collaborators on the latest brown dwarf project have models that complement his. Using data obtained by the Keck Telescope in Hawaii, they found that Gliese 229B fit their models in most respects, but not in the optical part of the spectrum. The optical part of the spectrum includes light waves that are visible to the human eye, plus a section of the spectrum between visible light and the infrared region that is not visible to the human eye. The brown dwarf's darkness in this part of the spectrum could not be caused by clouds, the scientists concluded. Its atmosphere is too warm to contain ice clouds like those on Jupiter and too cool to contain silicate clouds like those on low mass stars. Also, in parts of the spectrum where the brown dwarf is brighter, such as the near-infrared part of the spectrum, "the data look like there are no clouds at all -- a perfectly clear atmosphere," Marley said. "So there was this puzzle," he said. "It seemed to be cutting off light in one region (of the spectrum) but in other areas it looked just fine." While the astronomers are confident they have solved the puzzle of Gliese 229B's atmosphere, by analysis of its spectrum and an understanding of how different particles scatter light, the results don't necessarily apply to other brown dwarfs, Marley said. "Most of the other brown dwarfs that have been discovered are isolated," he said. Gliese 229B is orbiting a nearby star, and ultraviolet light from the star is a factor in the chemical reaction in the brown dwarf's atmosphere. "And this one is still the coldest one so far," he added -- another factor in the atmospheric makeup. Andrew Yee ayee@nova.astro.utoronto.ca Hа сегодня все, пока! =SANA=
    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: Researchers Searching for Light from E.T. (Forwarded) Привет всем! Вот, свалилось из Internet... Harvard University 3 December 1998 Researchers Searching for Light from E.T. By Maria Cristina Caballero and John Lenger, Harvard Gazette If E.T. won't call, maybe he'll shine a light on us instead. That's the hope of Harvard researchers involved in the search for extraterrestrial intelligence (SETI) who have unveiled a new experiment that involves scanning the heavens for flashes of laser light. Professor of Physics Paul Horowitz's laboratory recently installed the experiment at the Harvard-Smithsonian Oak Ridge Observatory in Harvard, Mass. The optical SETI (or OSETI) experiment has occasionally registered a signal similar to what one would expect if another civilization's laser were aimed at us. None of those signals has shown the regular repetitions that could indicate an intelligent hand behind them; but then, the researchers have just begun looking. Though such searches for laser lights from beyond our solar system have been done before, in an isolated and sporadic way, the Harvard experiment is the first broad-based and systematic search. Horowitz has had his ears to the skies for interstellar radio messages for the past 20 years. He directs Harvard's BETA project, which for the past three years has searched 600 million channels for radio signals broadcast by an intelligent civilization. Before BETA there was META, an 8.4 million-channel searching device that went on-line in 1985 and was supported in part by funds from E.T. director Steven Spielberg. While BETA continues its radio-wave search in full force, collecting the equivalent of a compact disc's worth of data every two seconds, none of the radio signals collected has yet been shown to be of intelligent origin. "After 20 years, maybe it's time to try something else," Horowitz says. The idea of analyzing light flashes from distant parts of the galaxy is not a new one, Horowitz explains. Charles Townes, who shared the Nobel Prize in Physics in 1964 for his work on masers and lasers, first raised the idea in a paper co-authored with R.N. Schwartz, "Interstellar and Interplanetary Communication by Optical Masers," that was published in the journal Nature in April 1961. But technology developed just within the past five years finally made it a viable project. "This is very much an experiment of the '90s," Horowitz says. The beauty of the new experiment, Horowitz explains, is that flashes of concentrated light are easy to detect and show up as distinct from other sources of illumination. If, for instance, Earthlings aim a high-intensity pulsed laser at a distant star, anyone watching from that star with a moderate-sized telescope will suddenly see a flash 1,000 times brighter than the light of our Sun -- "an efficient interstellar beacon." And since the brightness of starlight and laser light both decrease at the same rate, that particular high-intensity laser beam shot from Earth would always be 1,000 times brighter than the light from our Sun, no matter how far it travels. Reversing the direction, any extraterrestrial flash pointed the way of Earth would be easily distinguishable from the light of a distant star. That could make pulsed light the preferred method for communicating across galactic distances instead of radio waves. If you remember childhood games involving walkie-talkies and messages communicated by flashlight beams, you'll recall that flashlight beams were much more reliable than static-filled walkie-talkie transmissions, if not as dramatic. Horowitz, who has long been an optimist regarding the idea of extraterrestrial civilizations, cautions, however, that, "Maybe they're using 'zeta rays' to communicate, and the problem is we haven't discovered zeta rays yet." Still, the elegance and simplicity of the new laser-detection experiment is appealing. BETA took four years to build (at a cost of hundreds of thousands of dollars), involves enough high-end computer equipment to fill a large truck, and uses an 84-foot radio telescope. The OSETI equipment, funded by the Planetary Society, the SETI Institute, and the Bosack-Kruger Charitable Foundation, was put together in three months by Horowitz and fellow researchers Jonathan Wolff, Chip Coldwell, and Costas Papaliolios at a cost of less than $10,000. "It fit in the back seat of my Corolla," Horowitz says, describing the monitoring device as being as big as a box "for a large loaf of bread." It uses leftover light from a 61-inch telescope that already was engaged in a survey of 2,500 nearby solar-type stars, an experiment run by researchers Joe Caruso, David Latham, Robert Stefanik, and Joe Zajac. The simplicity of the new OSETI equipment means the experiment could easily be duplicated elsewhere. Researchers at the University of California at Berkeley, who have done some preliminary looking, are setting up an optical SETI experiment along the same lines, and their experiment will be operational soon. A more detailed description of Harvard's optical SETI experiment is on-line at http://mc.harvard.edu/hgroup.html, and contains a call for the SETI research community "to consider alternative OSETI strategies -- choice of wavelength, pulse widths and repetition rates, revisit times, etc. -- in an attempt to identify a particularly compelling a priori strategy, involving both sender and receiver, that could be the basis for major Earth-based OSETI receiving efforts in the near term." Optical SETI is an added tool for searching the heavens that has emerged just as the more traditional searches of radio frequencies are getting tougher. Darren Leigh, a recent Harvard Ph.D. in applied physics who oversees the BETA project, says that cellular phones in particular have made it harder to hear signals from outer space. As satellite transmissions increase, Leigh says, we are confronted by the possibility that our interest in talking with each other might mean less chance of hearing a call from extraterrestrials. Horowitz is optimistic about the optical SETI project, but 20 years of waiting have made him cautious. "I'll be excited when we get results," he says. PHOTO CAPTIONS: [http://www.news.harvard.edu/science/current_stories/3.Dec.98/ seti.3.dec.98.html] [Image 1] Part of the experiment's crew poses with the telescope being used for the SETI experiment. From left to right are researchers Costas Papaliolios, Chip Coldwell, Paul Horowitz, and Jonathan Wolff. A more detailed description of Harvard's optical SETI experiment is online [http://mc.harvard.edu/hgroup.html]. [Image 2] The OSETI equipment fit in Horowitz's Corolla; Jonathan Wolff (above) built most of the device. Andrew Yee ayee@nova.astro.utoronto.ca Hа сегодня все, пока! =SANA=
    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: Latest NEAR news not good Привет всем! Вот, свалилось из Internet... From mission control center ... Update on Aborted Burn At 5:20 p.m. today, Dec. 21, the NEAR mission team is still trying to reestablish communications with the spacecraft. Communications ceased at about 5:10 p.m. EST, Sunday, Dec. 20, during the first of four rendezvous burns that would put the spacecraft at optimum speed and location for a Jan. 10, 1999, rendezvous with asteroid 433 Eros. Doppler data collected at about 5:40 p.m. Dec. 20, leads team members to believe that the spacecraft was transmitting at that time. Around-the-clock strategy sessions are being held to correct the problem. If communications are not established by midnight tonight it is highly unlikely that the spacecraft will go into orbit on January 10. Because of the robust nature of the spacecraft design many alternatives are available to the team to ensure that the mission can weather schedule changes and still yield significant science return. Those alternatives will be reviewed once communications have been reestablished. Hа сегодня все, пока! =SANA=
    Дата: 22 декабря 1998 (1998-12-22) От: Alexander Bondugin Тема: Mars Climate Orbiter Update - December 21, 1998 Привет всем! Вот, свалилось из Internet... MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov Mars Climate Orbiter Mission Status December 21, 1998 Mars Climate Orbiter successfully completed its first trajectory correction maneuver at 1:33 p.m. Pacific Standard Time today to fine-tune its flight path. This maneuver removed a bias intentionally set by the vehicle that was designed to prevent the third stage of the Delta II launch vehicle from tagging along and colliding with Mars. It also removed a small launch injection error, putting the orbiter on course for its capture into orbit around Mars on September 23, 1999. The spacecraft began the turn to align its thrusters to the desired direction at 1:19 p.m. PST, fired the thrusters for 2.8 minutes, then turned back to its original orientation so that its solar panels would continue to generate electrical power. The maneuver changed the spacecraft's velocity by just 19.1 meters per second (42.7 miles per hour). This very slight change in flight course and velocity indicated the high degree of accuracy achieved during launch on December 11. Now on its way to Mars, the orbiter is in excellent health. An onboard software program recently uplinked to the spacecraft is regulating its thermal control and power requirements, as well as monitoring other subsystems. A health check of the Mars Color Imager and opening of the cooler door on the Pressure Modulator Infrared Radiometer are planned for Wednesday, December 23. Mars Climate Orbiter is currently about 2.87 million kilometers (1.75 million miles) from Earth, traveling at a velocity of about 11,950 kilometers per hour (7,290 miles per hour) relative to Earth. ##### Hа сегодня все, пока! =SANA=

    сайт служит астрономическому сообществу с 2005 года