NASA Lander Will Sprinkle Martian Soil For Microscope To ViewNASA Lander Will Sprinkle Martian Soil For Microscope To View
Tucson AZ (SPX) Jun 11, 2008 The team operating NASA's Phoenix Mars Lander plans to instruct the spacecraft in the next few days to use its Robotic Arm to sprinkle a spoonful of Martian soil onto a wheel that will rotate the sample into place for viewing by the spacecraft's Optical Microscope. Meanwhile, commands for Phoenix's activities today are to continue a set of atmosphere observations begun during the Martian evening earlier Tuesday in coordination with overhead passes of NASA's Mars Reconnaissance Orbiter. These take advantage of opportunities for instruments on Phoenix and on the orbiter to examine the same column of atmosphere simultaneously from above and below. "It allows us to put the Phoenix measurements into global perspective and gives a ground level calibration for the orbiter's measurements," said Phoenix Project Scientist Leslie Tamppari of NASA's Jet Propulsion Laboratory, Pasadena, Calif. On Monday, Phoenix tested delivering Martian soil by sprinkling it rather than dumping it. The positive result prompted researchers not only to proceed with plans for delivery to the microscope, but also to plan on sprinkling a sample in the near future into one of the eight ovens of an instrument that bakes and sniffs samples, the Thermal and Evolved-Gas Analyzer, or TEGA. A sample of clumpy soil dumped onto one TEGA oven on June 6 has yielded only a few particles passing through a mesh screen over the opening to the oven, even after additional vibration of the screen on Monday. The sprinkling method developed a few months ago by members of Phoenix's arm and microscope teams uses vibration of the tilted scoop by a motorized rasp to gently jostle some material out, instead of turning the scoop over to empty it. The rasp is located on the back of the scoop and will be used later in the mission to scrape up samples of subsurface ice. The first test of the sprinkling method Monday produced a layer of fine particles extending from a pile of about a tablespoon of soil. The practice placed the material on the top surface of the instrument suite that includes the microscope, the Microscopy, Electrochemistry and Conductivity Analyzer, or MECA. "This is good news," said Ray Arvidson of Washington University in St. Louis, lead scientist for the Robotic Arm. He said that the clumping tendency of Martian soil at the Phoenix site and some earlier landing sites comes from extremely fine particles filling in gaps between coarser, sand-size particles, perhaps together with an ingredient acting to cement particles together. Future soil samples may be prepared prior to delivery by chopping and scraping them with blades on the scoop. 23:07 - 11/6/2008 - Comment {yok} - Post CommentXena Awarded "Dwarf Planet" Status, IAU Rules; Solar System Now
The ruling effectively settles a year-long controversy about whether the spherical body announced last year and informally named "Xena" would rise to planetary status. Though somewhat larger than Pluto, the body has been informally known as "Xena" since the formal announcement of its discovery on July 29, 2005 by Brown and his co-discoverers, Chad Trujillo of the Gemini Observatory and David Rabinowitz of Yale University. Xena will now be known as the largest dwarf planet.
"I'm of course disappointed that Xena will not be the tenth planet, but I definitely support the IAU in this difficult and courageous decision," said Brown. "It is scientifically the right thing to do, and is a great step forward in astronomy.
"Pluto would never be considered a planet if it were discovered today, and I think the fact that we've now found one Kuiper-belt object bigger than Pluto underscores its shaky status." Pluto was discovered in 1930. Because of its distance and size, astronomers had no idea of its composition or other characteristics at the time. But having no reason to think that many other similar bodies would eventually be found in the outer reaches of the solar system-or that a new type of body even existed in the region-they assumed that designating the new discover as the ninth planet was a scientifically accurate decision.
However, the famed astronomer Gerard Kuiper later postulated that a region in the outer solar system could house a gigantic number of comet-like objects too faint to be seen with the telescopes of the day. The Kuiper belt, as it came to be called, was demonstrated to exist in the 1990s, and astronomers have been finding objects of varying size in the region ever since. Few if any astronomers had previously called for the Kuiper-belt objects to be called planets, because most were significantly smaller than Pluto. But the announcement of Xena's discovery raised a new need for a more precise definition of which objects are planets and which are not. According to Brown, the decision will pose a difficulty for a public that has been accustomed to thinking for the last 75 years that the solar system has nine planets.
"It's going to be a difficult thing to accept at first, but we will accept it eventually, and that's the right scientific and cultural thing to do," Brown says. In fact, the public has had some experience with the demotion of a planet in the past, although not in living memory. Astronomers discovered the asteroid Ceres on January 1, 1801--literally at the turn of the 19th century. Having no reason to suspect that a new class of celestial object had been found, scientists designated it the eighth planet (Uranus having been discovered some 20 years earlier).
Soon, several other asteroids were discovered, and these, too, were summarily designated as newly found planets. But when astronomers continued finding numerous other asteroids in the region (there are thought to be hundreds of thousands), the astronomical community in the early 1850s demoted Ceres and the others and coined the new term "asteroid."
Xena was discovered on January 8, 2005, at Palomar Observatory with the NASA-funded 48-inch Samuel Oschin Telescope. Xena is about 2,400 kilometers in diameter. A Kuiper-belt object like Pluto, but slightly less reddish-yellow, Xena is currently visible in the constellation Cetus to anyone with a top-quality amateur telescope.
Brown and his colleagues in late September announced that Xena has at least one moon. This body has been nicknamed Gabriella after Xena's sidekick on the television series. Xena is currently about 97 astronomical units from the sun (an astronomical unit is the distance between the sun and Earth), which means that it is some nine billion miles away at present. Xena is on a highly elliptical 560-year orbit, sweeping in as close to the sun as 38 astronomical units. Currently, however, it is nearly as far away as it ever gets.
However, Pluto's own elliptical orbit takes it as far away as 50 astronomical units from the sun during its 250-year trip around the sun. This means that Xena is sometimes much closer to Earth than Pluto-although never closer than Neptune.
Gabriella is about 250 kilometers in diameter and reflects only about 1 percent of the sunlight that its parent reflects. Because of its small size, Gabriella may very well be oddly shaped. Brown says that the study of Gabriella's orbit around Xena hasn't yet been fully determined. But once it is, the researchers will be able to derive the mass of Xena itself. That's because the entire mass of the system-Xena and Garbriella-orbits a common center of gravity. Therefore, once the researchers figure out the distance between the moon and its parent, how fast the moon revolves its parent, and how much the moon makes Xena wobble, then they'll know how much Xena weighs. And this information will lead to new insights on its composition.
Based on spectral data, the researchers think Xena is covered with a layer of methane that has seeped from the interior and frozen on the surface, As in the case of Pluto, the methane has undergone chemical transformations, probably due to the faint solar radiation, that has caused the methane layer to redden. But the methane surface on Xena is somewhat more yellowish than the reddish-yellow surface of Pluto, perhaps because Xena is farther from the sun. Brown and Trujillo first photographed Xena with the 48-inch Samuel Oschin Telescope on October 31, 2003. However, the object was so far away that its motion was not detected until they reanalyzed the data in January of 2005.
The search for new planets and other bodies in the Kuiper belt is funded by NASA. For more information on the program, see the Samuel Oschin Telescope's Web site at http://www.astro.caltech.edu/palomarnew/sot.html 21:37 - 29/8/2006 - Comment {yok} - Post CommentIAU 2006 General Assembly: Result of the IAU Resolution votes
24-August-2006, Prague: The first half of the Closing Ceremony of the 2006 International Astronomical Union (IAU) General Assembly has just concluded. The results of the Resolution votes are outlined here.
It is official: The 26th General Assembly for the International Astronomical Union was an astounding success! More than 2500 astronomers participated in six Symposia, 17 Joint Discussions, seven Special Sessions and four Special Sessions. New science results were vigorously discussed, new international collaborations were initiated, plans for future facilities put forward and much more. In addition to all the exciting astronomy discussed at the General Assembly, six IAU Resolutions were also passed at the Closing Ceremony of the General Assembly:
The IAU members gathered at the 2006 General Assembly agreed that a "planet" is defined as a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
This means that the Solar System consists of eight "planets" Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. A new distinct class of objects called "dwarf planets" was also decided. It was agreed that "planets" and "dwarf planets" are two distinct classes of objects. The first members of the "dwarf planet" category are Ceres, Pluto and 2003 UB313 (temporary name). More "dwarf planets" are expected to be announced by the IAU in the coming months and years. Currently a dozen candidate "dwarf planets" are listed on IAU's "dwarf planet" watchlist, which keeps changing as new objects are found and the physics of the existing candidates becomes better known.
The "dwarf planet" Pluto is recognised as an important proto-type of a new class of trans-Neptunian objects. The IAU will set up a process to name these objects. Below are the planet definition Resolutions that were passed. Notes for editors A press conference about the Closing Ceremony of the General Assembly, including the results of the planet-definition vote, will be held at 18:00, in Meeting Room 3.3 of the Prague Congress Center. (It will NOT be possible for journalists to ring in to this conference: they must be there in person.) The panel for the press conference will be:
This press conference will conclude around 18:30 CEST. The IAU is the international astronomical organisation that brings together distinguished astronomers from all nations of the world. Its mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Founded in 1919, the IAU is the world's largest professional body for astronomers. The IAU General Assembly is held every three years and is one of the largest and most diverse meetings on the astronomical community's calendar. 09:07 - 25/8/2006 - Comment {yok} - Post Comment
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PASADENA, Calif.--The International Astronomical Union (IAU) today downgraded the status of Pluto to that of a "dwarf planet," a designation that will also be applied to the spherical body discovered last year by California Institute of Technology planetary scientist Mike Brown and his colleagues. The decision means that only the rocky worlds of the inner solar system and the gas giants of the outer system will hereafter be designated as planets. 
