Science Special News

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Fourth orbiter to arrive at Mars on Friday

NASA's Mars Reconnaissance Orbiter is approaching Mars and, if maneuvers go well, will join three other Earth spacecraft in orbit around the planet. About 4:25 p.m. EST Friday the $720 million spacecraft will reduce its speed by 2,200 mph, and begin to orbit Mars, The Washington Post reported Monday. If all goes well -- 21 Mars missions have ended in disaster -- after six months of course and speed corrections, it will settle into a "science orbit" between 199 and 158 miles above the Martian surface, joining three currently operating satellites -- two from NASA and one from the European Space Agency, the Post said. There it will remain for two years, using inspecting the planet. After that time it will be sent into a higher orbit to become a communications relay satellite. The Mars Reconnaissance Orbiter has been operating flawlessly since its launch in August.

"But we are getting into the dangerous portion of the mission," says Jim Graf of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "A lot can go wrong, and if we don't succeed, we will fly right by the planet."

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New organ discovered in mice

After a century of scrutinizing the laboratory mouse, one might imagine that scientists would know the creature's body like the back of their own hands. Think again, because German researchers say they have discovered a whole new organ.Common knowledge holds that in mice, the thymus, a pinkish-grey lump of tissue that helps to produce the infection-fighting T cells of the immune system, is roughly the size of a pea and nestles in the chest above the heart. Now Hans-Reimer Rodewald at the University of Ulm in Germany, and his colleagues say they have discovered a smaller, second thymus hidden in the necks of lab mice. "I couldn't believe it for the first couple of months," Rodewald says. "2006 is not the time that you expect to change anatomy."The discovery raises questions about some immunology studies in mice. Researchers interested in the immune system often slice out the main thymus of mice in order to study how this system works without it, and how T cells are produced in the gut and skin.

The presence of a second thymus suggests that many of these mice still had a working thymus in their necks, which could have confounded the results. These studies may need to be re-examined, Rodewald suggests: "Some people are not going to like this."The discovery isn't a total surprise: biologists already knew that other mammals, including some humans, harbour an extra thymus in their necks. Studies from as early as the 1940s suggest that as many as five out of six human fetuses have a second thymus in the neck, says Clare Blackburn who studies the mammalian thymus at the University of Edinburgh, UK. There were also suggestions of a second mouse thymus in a report from the 1960s.

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Did Pentagon create orbital space plane ?

A prestigious aerospace magazine on Sunday laid out what it called "considerable evidence" that the U.S. military funded the development and testing of a small orbital space plane in the 1990s. In an article posted to its Web site, Aviation Week & Space Technology reported that the two-person "Blackstar" space vehicle may have made more than one orbital mission. But it said the project may have since been "quietly mothballed," possibly for budgetary or operational reasons.The report was met with skepticism from other aerospace industry observers, and even Aviation Week conceded that the evidence was inconclusive. In the report, senior editor William B. Scott said that Aviation Week has been investigating "myriad sightings of a two-stage-to-orbit system that could place a small military spaceplane in orbit" over the past 16 years."Now facing the possibility that this innovative 'Blackstar' system may have been shelved, we elected to share what we've learned about it with our readers, rather than let an intriguing technological breakthrough vanish into 'black world' history, known to only a few insiders," Scott wrote.Aviation Week reported that the "highly classified" project involved a large carrier aircraft called the SR-3, modeled on the XB-70 Valkyrie supersonic bomber of the 1960s, as well as a small space plane called the XOV (for "experimental orbital vehicle"). The mothership would carry the XOV under its fuselage, rise to high altitude, then release the space plane at supersonic speeds. After the release, the XOV would fire its rocket engines to rise into orbit, and the mothership would return to base.At the end of its mission, the XOV would return to Earth along a flight profile much like that of the space shuttle.



Aviation Week said the system was designed in the 1980s "for reconnaissance, satellite insertion and, possibly, weapons delivery." The report said the Pentagon could conceivably use the system to conduct surprise reconnaissance of foreign military activities that were hidden from regularly scheduled spy-satellite overflights.Scott wrote that "observed spaceplane landings have been reported" at Hurlburt Air Force Base in Florida, Kadena Air Base in Okinawa and Holloman Air Force Base in New Mexico. To preserve secrecy, the space planes were reportedly transported back to their home base in special C-5 Galaxy transports, and Blackstar's costs may have been charged to other projects such as the National Aero-Space Plane and the Navy's A-12 fighter, the magazine said.

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View of Easter Island disaster 'all wrong'

The first settlers on Easter Island didn't arrive until 1200 AD, up to 800 years later than previously thought, a new study suggests. The revised estimate is based on new radiocarbon dating of soil samples collected from one of oldest known sites on the island, which is in the South Pacific west of Chile.The finding challenges the widely held notion that Easter Island's civilization experienced a sudden collapse after centuries of slow growth. If correct, the finding would mean that the island's irreversible deforestation and construction of its famous Moai statues began almost immediately after Polynesian settlers first set foot on the island.The study, conducted by Terry Hunt of the University of Hawaii, Manoa and Carl Lipo of California State University, Long Beach, is detailed today in the online version of the journal Science.According to one widely held view, a small band of Polynesian settlers, perhaps no more than a few dozen people, arrived on the Easter Island sometime between 400 and 1000 AD.The settlers lived in harmony with the environment for hundreds of years and the population slowly grew. Some scientists estimate that at its height, Easter Island's population may have been as much as 20,000 people.

Around 1200 AD, the story goes, the inhabitants began cutting down the island's subtropical trees and giant palms in large numbers to build canoes and to transport the giant stone statues, which started going up around this time.The large-scale deforestation led to soil erosion and over a span of several centuries, the island's ability to support wildlife and farming was compromised. People began to starve. In a last ditch effort at survival, they became cannibals.The collapse of both the island's ecology and civilization was so complete that by the time the Dutch arrived in the 1700s, Easter Island was a sandy grassland void of nearly all its native wildlife; its human inhabitants were reduced to a starving population of 3,000 or less.This is the story pieced together by researchers over the past several decades, but Hunt and Lipo think it is wrong.

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Brain swapping comes of age

For more than two decades, Evan Balaban has honed his skills at manipulating embryonic tissue samples using tiny instruments of his own making. He can cut a small access window into a quail's egg, and using a scalpel no wider than a human hair, excise a few hundred thousand cells from the birds developing central nervous system. This is only the first step of the intricate process required to place this minuscule brain into another animal's head. Some of these surgeries end in untimely death for brain-transplanted embryos, but Balaban says he has elevated the typical survival rate from less than 20% to more than 60%. That was unimaginable in the 1950s, he says, when success was more along the lines of one or two in 1,000, and some researchers "were doing this with piano wire."But don't cue the maniacal laughter just yet. As much T.H. Morgan as it is Dr. Moreau, brain-swapping research is coming into its own, with the potential to answer questions other technologies can't, says Balaban.

This associate professor of behavioral neuroscience at McGill University in Montreal is unfazed by the contrast between the glitz of kindred work, such as stem cell implantation, and the whiff of gothic horror that accompanies his work.Far from being a throwback, he insists, brain swapping is "really working at the right level for answering a lot of interesting questions about brain development and behavior," and techniques are improving all the time. Not until two or three decades ago did biologists understand brain circuitry well enough to make good scientific use of brain transplants, though they have been technically feasible since H.G. Wells' time. Since then, researchers have swapped the brains of various species of frogs and salamanders, as well as ducks, in addition to the quails and chicks that Balaban uses. He plans on trying it on songbirds too.

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For more than two decades, Evan Balaban has honed his skills at manipulating embryonic tissue samples using tiny instruments of his own making. He can cut a small access window into a quail's egg, and using a scalpel no wider than a human hair, excise a few hundred thousand cells from the birds developing central nervous system. This is only the first step of the intricate process required to place this minuscule brain into another animal's head. Some of these surgeries end in untimely death for brain-transplanted embryos, but Balaban says he has elevated the typical survival rate from less than 20% to more than 60%. That was unimaginable in the 1950s, he says, when success was more along the lines of one or two in 1,000, and some researchers "were doing this with piano wire."But don't cue the maniacal laughter just yet. As much T.H. Morgan as it is Dr. Moreau, brain-swapping research is coming into its own, with the potential to answer questions other technologies can't, says Balaban.

This associate professor of behavioral neuroscience at McGill University in Montreal is unfazed by the contrast between the glitz of kindred work, such as stem cell implantation, and the whiff of gothic horror that accompanies his work.Far from being a throwback, he insists, brain swapping is "really working at the right level for answering a lot of interesting questions about brain development and behavior," and techniques are improving all the time. Not until two or three decades ago did biologists understand brain circuitry well enough to make good scientific use of brain transplants, though they have been technically feasible since H.G. Wells' time. Since then, researchers have swapped the brains of various species of frogs and salamanders, as well as ducks, in addition to the quails and chicks that Balaban uses. He plans on trying it on songbirds too.

age intori beshe man maghzamo ba maghze anishtan avaz mikonam

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Huge impact crater found in Egypt

giant crater made by a meteorite impact millions of years ago has been discovered in Egypt's western desert. Boston University experts found the 31km (19 mile) wide crater while studying satellite images of the area. It is more than twice the size of the next largest Saharan impact depression and more than 25 times the size of Arizona's famous Meteor Crater. The American team that found it says its sheer size may have helped it escape detection all these years. The structure, which has an outer rim surrounding an inner ring, has been named "Kebira", which means "large" in Arabic and also relates to the crater's physical location on the northern tip of the Gilf Kebir region in southwest Egypt. "Kebira may have escaped recognition because it is so large," said Dr Farouk El-Baz, director of the Boston University Center for Remote Sensing, where the find was made.



"Also, the search for craters typically concentrates on small features, especially those that can be identified on the ground. The advantage of a view from space is that it allows us to see regional patterns and the big picture." Water and wind erosion may also have helped hide its extra-terrestrial origin. The heat from this impact may be responsible for the extensive field of "Desert Glass", yellow-green silica glass fragments found on the desert surface between the giant dunes of the Great Sand Sea in southwestern Egypt.

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Mars Reconnaissance Orbiter reaches target

With a crucially timed firing of its main engines today, NASA's new mission to Mars successfully put itself into orbit around the red planet. The spacecraft, Mars Reconnaissance Orbiter, will provide more science data than all previous Mars missions combined. Signals received from the spacecraft at 2:16 p.m. Pacific Time after it emerged from its first pass behind Mars set off cheers and applause in control rooms at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and at Lockheed Martin Space Systems, Denver. "This is a great milestone to have accomplished, but it's just one of many milestones before we can open the champagne," said Colleen Hartman, deputy associate administrator for NASA's Science Mission Directorate. "Once we are in the prime science orbit, the spacecraft will perform observations of the atmosphere, surface, and subsurface of Mars in unprecedented detail."

The spacecraft traveled about 500 million kilometers (310 million miles) to reach Mars after its launch from Florida on Aug. 12, 2005. It needed to use its main thrusters as it neared the planet in order to slow itself enough for Mars' gravity to capture it. The thruster firing began while the spacecraft was still in radio contact with Earth, but needed to end during a tense half hour of radio silence while the spacecraft flew behind Mars. "Our spacecraft has finally become an orbiter," said JPL's Jim Graf, project manager for the mission. "The celebration feels great, but it will be very brief because before we start our main science phase, we still have six months of challenging work to adjust the orbit to the right size and shape." For the next half-year, the mission will use hundreds of carefully calculated dips into Mars' atmosphere in a process called "aerobraking." This will shrink its orbit from the elongated ellipse it is now flying, to a nearly circular two-hour orbit. For the mission's principal science phase, scheduled to begin in November, the desired orbit is a nearly circular loop ranging from 320 kilometers (199 miles) to 255 kilometers (158 miles) in altitude, lower than any previous Mars orbiter. To go directly into such an orbit instead of using aerobraking, the mission would have needed to carry about 70 percent more fuel when it launched. The instruments on Mars Reconnaissance Orbiter will examine the planet from this low-altitude orbit. A spectrometer will map water-related minerals in patches as small as a baseball infield. A radar instrument will probe for underground layers of rock and water.

One telescopic camera will resolve features as small as a card table. Another will put the highest-resolution images into broader context. A color camera will monitor the entire planet daily for changes in weather. A radiometer will check each layer of the atmosphere for variations in temperature, water vapor and dust. "The missions currently at Mars have each advanced what we know about the presence and history of water on Mars, and one of the main goals for Mars Reconnaissance Orbiter is to decipher when water was on the surface and where it is now," said JPL's Dr. Richard Zurek, project scientist for the mission. "Water is essential for life, so that will help focus future studies of whether Mars has ever supported life."

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