SETI [skyline] S&T's News Bulletin for July 9, 1999


Larry Klaes (lklaes@bbn.com)
Sun, 11 Jul 1999 19:47:24 -0400


>Date: Fri, 9 Jul 1999 23:13:19 MDT
>From: "John Wagoner" <stargate@astromax.com>
>To: skyline@astromax.com
>X-Mailer: <IMail v5.04>
>Subject: [skyline] S&T's News Bulletin for July 9, 1999
>Sender: skyline-owner@astromax.com
>Reply-To: skyline@astromax.com
>
> =======================
> SKY & TELESCOPE's
> WEEKLY NEWS BULLETIN
> AND STARGAZING CALENDAR
>
> July 9, 1999
> =======================
>
>COMET LANDERS: ONE UP, ONE DOWN
>
>There's good news and bad news for astronomy enthusiasts interested in
>seeing a comet up close. First the good news. The European Space Agency has
>unveiled designs for its Rosetta orbiter and lander, to be launched toward
>Comet 46P/Wirtanen in 2003. During its eight-year interplanetary voyage,
>Rosetta will fly past two asteroids. According to ESA scientists, the
>mission's aim is "to study the origin of comets, the relationship between
>cometary and interstellar material, and its implications with regard to the
>origin of the solar system." Now the bad news. NASA had planned to study
>the same things and was hoping to beat ESA to a comet by landing its
>Champollion spacecraft on 9P/Tempel 1 in 2006. But planetary scientists
>have learned that NASA has proposed cancelling the mission due to a
>shortage of funds. The Planetary Society and others who support
>solar-system exploration hope to convince the U.S. Congress to reverse this
>decision. Even if Champollion does lose its head to the budget axe, NASA
>still has two comet missions in the pipeline, though neither one involves a
>soft landing. Stardust is now en route to a 2004 encounter with Comet Wild
>2. In 2006 the spacecraft will return to Earth with samples of cometary and
>interplanetary dust. And earlier this week NASA announced plans to launch
>Deep Impact to Comet 9P/Tempel 1 in January 2004. Upon arrival 18 months
>later the probe will smash a projectile into the comet to excavate a huge
>crater, then study the icy debris and the pristine material exposed by the
>blast. (See additional information below.)
>
>NEW ZEALAND BOLIDE
>
>A meteor streaked through the sky and exploded over northern New Zealand on
>July 8th, prompting hundreds of calls to local authorities. The fireball
>appeared shortly after 4 o'clock in the afternoon New Zealand Standard Time
>and shone "as bright[ly] as the Sun," according to John Field, press
>officer at the Carter Observatory in Wellington. The explosion produced a
>sonic boom and a cloud of yellowish vapor. Scientists from the One Tree
>Hill Observatory are using eyewitness accounts to reconstruct the bolide's
>trajectory. That information will help narrow the search for any fragments
>that might have survived the fall to Earth. According to observatory
>director Ian Griffin the search has already been narrowed to a
>100-kilometer-long strip that begins in Taranaki and extends out over the
>ocean. Although there have been numerous reports of debris falling to the
>ground, search parties have not yet turned up any remnants. Joel Schiff,
>editor of Meteorite! magazine, said meteorites from the fall could be as
>small as a pea or as large as an apple. The day after the incident a dealer
>in New York offered $25,000 for rubble from the bolide.
>
>A "GO!" FOR CHANDRA
>
>It's official: NASA plans to launch the Space Shuttle Columbia from Cape
>Canaveral at 12:36 a.m. Eastern Time on July 20th. Shortly after reaching
>orbit Columbia's astronauts will deploy the Chandra X-ray Observatory.
>Chandra is the X-ray analog of a large optical telescope, providing
>high-resolution, wide-field images over a broad range of X-ray energies.
>Astronomers eagerly await Chandra's crisp images of clusters of newborn
>stars, galaxies interacting within remote clusters, and supernova ejecta
>crashing into interstellar gas. Chandra also offers excellent spectral
>resolution, allowing the temperatures, densities, and elemental abundances
>of hot plasma clouds to be inferred from their atomic emissions. Redshifts
>and blueshifts of X-ray spectral features, caused by the Doppler effect,
>will tell researchers how rapidly ultrahot gas is flowing between galaxies
>in clusters and spiraling toward the event horizons of stellar black holes.
>And Chandra's ability to measure intensity variations on time scales of
>microseconds will enable us to gauge the rotation rates of pulsars --
>highly magnetic neutron stars -- spinning dozens of times per second. See
>Sky & Telescope's August 1999 issue for a complete preview of the mission.
>
>SUNSPOTTING
>
>The Sun's magnetic-activity cycle is nearing its 11-year peak, and that
>means the number of dark spots on our daytime star is on the rise. With a
>safe solar filter over the front of your telescope, you can view sunspots
>easily on any clear day. Several large spot groups are marching across the
>Sun's visible face this week, as shown in the accompanying image. Bright
>regions called faculae are also plainly visible. Astronomers used to think
>that sunspots lowered the overall energy output of the Sun, but recent
>studies have shown that faculae more than compensate for the spots, so that
>a heavily spotted Sun is actually putting out a little more energy than
>average.
>
>PETE CONRAD, 1930-1999
>
>Former NASA astronaut Charles "Pete" Conrad died last night following a
>motorcycle accident near Ojai, California. He was 69 years old. A veteran
>of four space flights, Conrad is best remembered as commander of Apollo 12,
>which achieved the second manned lunar landing. He also spent 28 days
>aboard Skylab and flew on two Gemini missions. Since his retirement from
>NASA in 1974, Conrad had continued to work in aerospace, most recently on
>the development of economical launch vehicles. Conrad's irreverent style
>endeared him to the press and public. Standing barely 5 feet 6 inches tall
>and sporting an impish, gap-toothed grin, he began his Apollo 12 moonwalk
>with a play on Neil Armstrong's historic first words on the Moon four
>months earlier. Jumping from the last rung of the lunar module's ladder to
>the footpad on the surface about three feet below, Conrad quipped,
>"Whoopie! Man, that may have been a small one for Neil, but that's a long
>one for me."
>
>A STELLAFANE REPRIEVE?
>
>The dark skies over Springfield, Vermont -- home of the annual Stellafane
>star party -- were threatened last week when residents of the town voted
>1,633 to 1,564 in favor of a state plan to build a 350-bed prison just four
>miles from Stellafane's Breezy Hill. Members of the Springfield Telescope
>Makers and astronomers nationwide fear the prison's lights will destroy the
>night skies that have drawn stargazers to the site for the last 75 years.
>But a town law might provide just the reprieve dark sky activists and other
>prison opponents need. In the event of such a close outcome -- the measure
>passed by only 69 votes, or 2 percent of those cast -- the law allows a
>repeat election if 5 percent of registered voters petition for one. That
>requirement was met on July 7th. The referendum will likely happen in
>September, giving Stellafane's champions more time to publicize their
>cause. This year's star party is scheduled for the weekend of August 13th,
>and prison opponents hope Springfield residents will note how dark skies
>translate into tourist dollars before they go to the polls again. According
>to Maryann Arrien, president of the Springfield Telescope Makers, the
>referendum "doesn't necessarily mean the vote will go in our favor this
>time, but we can always hope."
>
>SOLAR MYSTERY EXPLAINED
>
>You might think astronomers would know virtually everything about our Sun,
>the nearest star and the only one that can be studied at high resolution.
>But old Sol still surprises us from time to time. In the latest instance,
>space scientists have discovered magnetic waves in the corona, the Sun's
>million-degree outer atmosphere. In so doing, they appear to have resolved
>a long-standing mystery: how do charged particles streaming from the Sun
>accelerate to speeds of 800 kilometers (500 miles) per second? Electrons
>and ions spiraling around magnetic-field lines can only get up to about
>half that speed, according to theorists' calculations. But new observations
>from the European Space Agency's Solar and Heliospheric Observatory (SOHO)
>and NASA's SPARTAN 201 satellite show that the Sun's magnetic-field lines
>wiggle back and forth rapidly. When the period of oscillation matches the
>period with which certain ions spiral around the field lines, those ions
>pick up extra energy and move faster, just as a child on a swing moves
>faster by pumping his or her legs in rhythm with the swing.
>
>NEW DISCOVERY MISSIONS
>
>Astronomers at NASA headquarters have announced that the next two missions
>in the agency's Discovery program will be a Mercury orbiter and a comet
>probe. The Mercury Surface, Space Environment, Geochemistry, and Ranging
>mission, or MESSENGER, will be the first spacecraft to visit the solar
>system's innermost planet since Mariner 10 made three flybys in 1974-75. To
>be launched in 2004 aboard a Delta rocket, MESSENGER will fly past Venus in
>2006 and again in 2007, make two flybys of Mercury in 2008, and then settle
>into orbit around the latter in 2009. Seven instruments will create the
>first global map of Mercury's scorched, crater-pocked surface and study the
>planet's interior and magnetosphere. Deep Impact was the name of a recent
>blockbuster movie, but it's also the name of a NASA probe to be launched in
>2004 toward periodic Comet P/Tempel 1. Upon arrival a year later, the
>spacecraft will fire a 500-kilogram (1,100-pound) projectile into the
>comet's surface, blasting a hole the size of a football field and deep
>enough to swallow a seven-story building. Instruments aboard the probe --
>and powerful telescopes on Earth -- will then examine the icy debris and
>the newly exposed pristine material on the floor and walls of the crater.
>Like the Lunar Prospector and Near Earth Asteroid Rendezvous (NEAR)
>missions before them, MESSENGER and Deep Impact will be built mainly using
>proven technologies and off-the-shelf components, hallmarks of the
>Discovery program's "faster, better, cheaper" philosophy to fly a large
>number of small missions rather than a small number of large (i.e.,
>billion-dollar) ones. Each mission will cost less than $300 million from
>start to finish.
>
>=============================
>THIS WEEK'S "SKY AT A GLANCE"
>=============================
>
>Some daily events in the changing sky, from the editors of SKY & TELESCOPE.
>
>JULY 11 -- SUNDAY
>
> * Venus and vastly fainter Regulus appear closest together this evening,
>only 1.25 degrees apart. Take a look with binoculars; they're low in the
>west in twilight.
>
>JULY 12 -- MONDAY
>
> * New Moon (exact at 10:24 p.m. EDT).
>
>JULY 13 -- TUESDAY
>
> * Look high in the northwest after dark for the Big Dipper, hanging bowl
>down. The bottom two stars of the bowl point to the right toward dim
>Polaris, the North Star, about three fist-widths at arm's length away.
>Polaris forms the end of the handle of the very dim Little Dipper, which
>floats directly upward from it at this time of year.
>
>JULY 14 -- WEDNESDAY
>
> * Venus reaches greatest brilliancy, magnitude -4.5.
>
>JULY 15 -- THURSDAY
>
> * There's a beautiful triangle of the crescent Moon, bright Venus, and
>faint Regulus (to their right) low in the west during twilight. Binoculars
>will give a lovely view.
>
>JULY 16 -- FRIDAY
>
> * By this evening, the Moon has moved well to the upper left of Venus and
>Regulus in the western twilight.
>
>JULY 17 -- SATURDAY
>
> * The Moon, thicker now, appears almost midway between Venus (far to its
>lower right) and Spica and Mars (far to the Moon's left).
>
>==========================
>THIS WEEK'S PLANET ROUNDUP
>==========================
>
>MERCURY is hidden in the glow of sunset.
>
>VENUS is the bright "Evening Star" low in the west at dusk. The much
>fainter star a little above it or to its right is Regulus.
>
>MARS (magnitude -0.3) shines orange in the southwest during evening. The
>fainter star to its right or lower right is blue-white Spica. In a
>telescope, Mars is only about 10.5 arcseconds in diameter and shrinking.
>
>JUPITER (magnitude -2.3) rises around 1 a.m. local daylight saving time and
>shines high in the east-southeast by dawn.
>
>SATURN (magnitude +0.1) is the dimmer "star" 13 degrees to the lower left
>of Jupiter (somewhat more than the width of your fist at arm's length).
>
>URANUS and NEPTUNE, dim at magnitudes 6 and 8, respectively, are well up in
>the southeast by midnight. See the finder chart in the May Sky & Telescope,
>page 108.
>
>PLUTO, extremely dim at magnitude 14, is in Ophiuchus in the south right
>after dark. See the finder chart in the March Sky & Telescope, page 103.
>
>(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 Daylight Time, EDT, equals Universal Time
>minus 4 hours.)
>
>============================================================
>Copyright 1999 Sky Publishing Corporation. S&T's Weekly News Bulletin and Sky
>at a Glance stargazing calendar are provided as a service to the astronomical
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>



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