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SPACE & SCIENCE NEWS: December 2000
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Ganymede and Jupiter flybys Dec 29, 2000
Cassini closing in on Jupiter Dec 24, 2000
Pluto-Charon probe back under consideration Dec 21, 2000
Landing site chosen for Beagle 2 Dec 20, 2000
Plans to drill into the Chicxulub crater Dec 19, 2000
An ocean for Ganymede Dec 17, 2000
Magnetite in Mars meteorite biogenic conclude researchers Dec 13, 2000
Three new extrasolar planets in the Southern Hemisphere Dec 11, 2000
Four new moons for Saturn Dec 10, 2000
The real starship(s) Voyager Dec 7, 2000
More images and coverage of Martian layered rocks Dec 5, 2000
Evidence of sedimentary rock layers on Mars Dec 4, 2000
Ancient sea and lake beds found on Mars Dec 3, 2000
Major Mars announcement to be made on Dec. 7 Dec 2, 2000
Lunar meteorites clue to intense Earth bombardment 4 billion years ago Dec 1, 2000



Ganymede
Ganymede and Jupiter flybys
(Dec. 29, 2000)


Galileo skimmed over the surface of Jupiter's (and the solar system's) largest moon, Ganymede, yesterday, at a distance of only 2,326 km. Ganymede is becoming of increasing interest to astrobiologists in light of recent claims that, like Europa, it may harbor an underground watery ocean. Cassini, meanwhile, is heading toward its closest approach to Jupiter tomorrow at a distance of 9.7 million km. Happily, it is taking pictures once again now that all of its reaction wheels are fully functional.

For more, visit the homepages of the Galileo and Cassini missions.

Cassini
Cassini closing in on Jupiter
(Dec. 24, 2000)


The earliest seafloor hydrothermal vents – supposedly more than three billion years old – may be nothing more than deposits from underground springs active in the last few thousand years. That is the claim of two US geologists who carried out a new analysis of rocks from South Africa which were previously dated to the Archaean period – when life first began to diversify. The findings could have important implications for our understanding of the early Earth and the microbial life forms that lived there. But one authority on the geology of the Barberton greenstone belt – where the rocks are found – launched a vigorous defense of evidence that they contain ancient hydrothermal vents.

Read more. Source: BBC

Pluto probe
Pluto-Charon probe back under consideration
(Dec. 21, 2000)


After recently canceling the long-heralded mission to Pluto and its moon Charon, NASA has revived the project. Pluto is the only major world in the Solar System not yet examined at close range and planetary astronomers had protested that cancellation of the probe meant wasting an opportunity to study the planet's atmosphere. As Pluto moves further from the Sun its thin atmosphere will freeze out and not build up again for another two centuries. Launch in 2004 Will enable a flyby in around 2014. NASA will make a firm decision about the probe over the coming months.

For more, go here.

Landing site chosen for Beagle 2
(Dec. 20, 2000)


ESA has announced that the Mars Express lander, Beagle 2, will touch down on Isidis Planitia, a large flat region that overlies the boundary between the ancient highlands and the northern plains. The region appears to be a sedimentary basin where traces of life could have been preserved, if primitive life really did exist at some time on Mars. For more, go here (ESA) and here (BBC).

asteroid impact
Plans to drill into the Chicxulub crater
(Dec. 19, 2000)


Buck Sharpton of the Department of Geology and Geophysics, University of Alaska, and his colleagues plan to drill 2.4 km into the crater linked to the demise of the dinosaurs (see Chicxulub crater. The researchers announced their intention at the autumn meeting of the American Geophysical Union, in San Francisco. The drilling site is about 80 kilometres south of Merida, Mexico. Results of the work will hopefully shed light on the dynamics of the impact and its environmental consequences. For more, go here.

Ganymede
An ocean for Ganymede?
(Dec. 17, 2000)


University of California scientists claim to have found evidence of an ocean of salt water on Jupiter's moon Ganymede based on magnetic field data returned by the Galileo probe. The measurements suggest a melted layer several kilometers deep some 200 km underground. Other researchers have identified what appear to be hydrated salt minerals on the moon's surface, possibly the result of brine making its way to the surface by eruptions or through cracks – the same as is believed to have happened on Europa. The hypothesis of water on what is the largest satellite in the Solar Systems has been boosted by new, high-resolution images of Ganymede sent back by Galileo. The images hint that water or slushy ice may have surfaced through the fractured crust to create smooth areas in between separated areas of crust.

For more, go here.

Hexagonal magnetite crystals in ALH 84001
Magnetite in Mars meteorite biogenic conclude researchers
(Dec. 13, 2000)


A team of researchers has published further evidence in the December issue of Geochimica et Cosmochimica Acta that certain magnetite crystals embedded in the Martian meteorite ALH 84001 are of a type produced only by a biological process unique to magnetotactic bacteria. Dennis Bazylinski, associate professor of microbiology at Iowa State University and a member of the team, said: "Finding these type of magnetic crystals in any material from another planet is an amazing and important finding." The researchers discovered that about one-fourth of the magnetites in the meteorite are identical to the magnetites produced by a strain of magnetotactic bacteria called MV-1, which have been isolated and studied extensively by Bazylinski. "There is currently no known chemical means of producing these magnetite crystals with their unique morphologies," said Bazylinski. "The significance to astrobiology and geobiology is that many scientists have been searching for 'biomarkers' for life, that is, chemical, isotopic, and/or mineral indications that life was present, either in extreme habitats or in ancient materials on Earth and, of course, now in extraterrestrial materials. The need for biomarkers is obvious and these magnetite crystals might prove to be an excellent biomarker." Since the team began the research in 1996, observations from the Mars Global Surveyor have indicated that Mars had a strong magnetic field at about time that the carbonate containing the unique magnetites was formed. "Now we are trying to answer the question of whether magnetotactic bacteria could have actually lived on Mars," Bazylinski said. "And we have found certain aspects of their metabolism which suggest that they might have been able to do so."

For more, go here (spaceref), here (Spaceflight Now) and here (BBC).

Three new extrasolar planets in the Southern Hemisphere
(Dec. 11, 2000)


An international team of astronomers, using the Anglo-Australian Telescope has found three new planets circling around Sun-like stars. One of the planets, estimated to be about the size of Jupiter, lies in the habitable zone of its parent star, epsilon Reticulum. Another is a "hot Jupiter" lying just 6 million kilometres from HD 179949 in the constellation Sagittarius. The third is almost twice as massive as Jupiter and circles Mu Arae in an orbit slightly larger than that of Mars. These are exciting results because they confirm that scientists are starting to find planets in more conventional orbits, further away from their host stars. As Alan Penny, a member of the discovery team, points out: "Two of these planets are Earth- and Mars-distances from their stars, so we are now working our way out as the survey techniques get more sensitive."

For more, go here.

Four new moons for Saturn
(Dec. 10, 2000)


An international team of astronomers using the 3.6-meter Canada-France-Hawaii Telescope on Mauna Kea, Hawaii, has announced the discovery of four new moons around Saturn. Temporarily designated S/2000 S7 through S/2000 S10, they appear to be similar in nature to the six other moons the same team found recently in the Saturn system. They are all suspected of having once been Centaurs – icy dwarf objects that orbit the Sun between Saturn and Uranus. The new discoveries brings Saturn's satellite complement to 28, compared with moon tallies of 21 for Uranus, 18 for Jupiter, 8 for Neptune, 2 for Mars, 1 each for Earth and Pluto, and none for Mercury and Venus – a grand solar system total of 79. Further observations over the coming months will be needed to confirm the findings and establish accurate orbital details.

For more, go here.

Voyager spacecraft
The real starship(s) Voyager
(Dec. 7, 2000)


Far beyond the orbit of Pluto, the two Voyager spacecraft (together with Pioneer's 10 and 11) are starbound on solar escape trajectories. The latest status report reveals that Voyager 1 is now 12.00 billion km from the Sun, traveling at 38.6 km/s, while its sister probe Voyager 2 is 9.45 billion km from its home star and moving at 35.7 km/s. Signals from Earth take 11 hr 7 min and 8 hr 45 min, respectively, to reach these lonely travelers. Both probes remain active, taking measurements of their magnetic, particle and radiation environments as they head toward interstellar space. The best definition of where interplanetary space ends and interstellar space begins is perhaps the heliopause – the boundary where the Sun's magnetic influence gives way to that of the interstellar medium. Both Voyagers are still some distance from the heliopause, but instruments on the craft have picked up signals that may be coming from the so-called termination shock – the zone where the solar wind suddenly slows down from supersonic to subsonic speed, creating a shock wave. Before the Voyagers travel beyond the heliopause into interstellar space, they will pass through this termination shock. Data being returned from the spacecraft suggest that they may reach the termination shock in the next three to five years, and the heliopause itself within a decade. With luck one or both probes may still be active as they penetrate into interstellar void for the first time. And then? In about 40,000 years, Voyager 1 will drift within 1.6 light years (9.3 trillion miles) of AC+79 3888, a star in the constellation of Camelopardalis. In some 296,000 years, Voyager 2 will pass Sirius, the brightest star in our sky, at a distance of about 4.3 light years (25 trillion miles). Not quite up to warp drive standards, but these Voyagers do have the advantage of being real!

More images and coverage of Martian layered rocks
(Dec. 5, 2000)


For newly released pictures and the latest reports on this breaking story, go here (BBC news), here (Planetary Society), and here (pictures from Science journal).

Layered outcrops on the faces of cliffs
Evidence of sedimentary rock layers on Mars
(Dec. 4, 2000)


New images from Mars Global Surveyor show clear evidence of sedimentary rocks on Mars dating back more than 3.5 million years. If life ever existed on the Red Planet, its remains may well be found as fossils within these apparently water-lain beds. The strata have been found inside craters, between craters and within canyons such as Valles Marineris, suggesting that they may have been deposited in lakes within these basins. Researchers Michael Malin and Kenneth Edgett will be announcing their results on Thursday at a press conference and in this week's issue of Science.

For more, go here.

Ancient sea and lake beds found on Mars
(Dec. 3, 2000)


NASA's big announcement to be made this Thursday (Dec. 7) and in Science is that images from Mars Global Surveyor show conclusively evidence of sedimentation that could only be the result of material that has accumulated at the bottom of bodies of water on Mars billions of years ago. These ancient beds, which may contain fossil traces of Martian life if it ever appeared, will become the focal point of investigation for the next generation of Mars landers, including Beagle 2, scheduled for launch in June 2003. Coincidentally, Colin Pillinger at the Open University in England, who heads the Beagle 2 project, will announce that he has raised the full 330m pounds ($45m) needed for the UK mission. He has just been offered 39m pounds by the European Space Agency, with the rest coming from commercial sponsors. More on this story over the next few days.

Major Mars Announcement to be made by NASA on Thursday, Dec. 7
(Dec. 2, 2000)


What is being described as the "most significant discovery yet" by a team of researchers involved with NASA's Mars Global Surveyor currently orbiting the Red Planet will be announced next Thursday, according to the space agency. Imaging scientists Michael Malin and Ken Edgett, who produced evidence of Martian "gully washers" a few months ago, will make their announcement at a Space Science Update scheduled for 2:00 p.m. EST (1900 GMT) on Thursday, December 7. Their findings are being published in the December 8 issue of Science.

Lunar meteorite found in the Libya desert
Lunar meteorites speak of intense Earth bombardment 4 billion years ago
(Dec.1, 2000)


New research carried out on four of the 20 known lunar meteorites, by Barbara Anne Cohen and colleagues at the University of Arizona in this weeks's Science, lends support to the view that the Moon and Earth were intensely bombarded between about 4 and 3.8 billion years ago. The rocks examined in the study probably came from all parts of the Moon and all were molten some 3.9 billion years ago. The bombardment that melted the Moon would, researchers believe, have been even more intense on the Earth, with its greater gravity, probably frustrating early attempts by life to get started. Biogenic traces have been found in rocks dating back 3.8 billion years, however, leaving very little time for biology to get off the ground after the intense bombardment ended. Did life emerge somehow during the heavy bombardment era? Or can biogenesis take place in so short a period – under 100 million years?

For more, go here.

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