Phoenix Takes Highest Resolution Image Ever of Dust and Sand on Mars

This mosaic of four side-by-side microscope images shows a 3 millimeter (0.12 inch) diameter silicone target after it has been exposed to dust kicked up by the landing. It is the highest resolution image of dust and sand ever acquired on Mars.

This mosaic of four side-by-side microscope images (one a color composite) was acquired by the Optical Microscope, a part of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument suite on NASA’s Phoenix Mars Lander.

Taken on the ninth Martian day of the mission, or Sol 9 (June 3, 2008), the image shows a 3 millimeter (0.12 inch) diameter silicone target after it has been exposed to dust kicked up by the landing. It is the highest resolution image of dust and sand ever acquired on Mars. The silicone substrate provides a sticky surface for holding the particles to be examined by the microscope.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

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Newly discovered extrasolar planet is the smallest known and has smallest host star

Astronomers have discovered an extrasolar planet only three times more massive than our own, the smallest yet observed orbiting a normal star. The star itself is not large, perhaps as little as one twentieth the mass of our Sun, suggesting to the research team that relatively common low-mass stars may present good candidates for hosting Earth-like planets.

Led by David Bennett of the University of Notre Dame, the international research team presents its findings in a press conference Monday, June 2, 2008 at the American Astronomical Society Meeting in St. Louis, Mo.

“Our discovery indicates that that even the lowest mass stars can host planets,” says Bennett. “No planets have previously been found to orbit stars with masses less than about 20 percent that of the Sun, but this finding indicates that even the smallest stars can host planets.”

The astronomers used a technique called gravitational microlensing to find the planet, a method that can potentially find planets one-tenth the mass of our own.

The gravitational microlensing technique, which came from Einstein’s General Theory of Relativity, relies upon observations of stars that brighten when an object such as another star passes directly in front of them (relative to an observer, in this case on Earth). The gravity of the passing star acts as a lens, much like a giant magnifying glass. If a planet is orbiting the passing star, its presence is revealed in the way the background star brightens. A full explanation of the technique follows this release.

“This discovery demonstrates the sensitivity of the microlensing method for finding low-mass planets, and we are hoping to discover the first Earth-mass planet in the near future,” said Bennett.

Using standard nomenclature, the star hosting the newly discovered planet is dubbed MOA-2007-BLG-192L with MOA indicating the observatory, 2007 designating the year the microlensing event occurred, BLG standing for bulge, 192 indicating the 192nd microlensing observation by MOA in that year and the L indicating the lens star as opposed to the background star further in the distance. The planet maintains the name but adds a letter designating it as an additional object in the star’s solar system, so it is called MOA-2007-BLG-192Lb.

MOA-2007-BLG-192L resides 3,000 light years away and is classified as either a low-mass hydrogen burning star, one that sustains nuclear reactions in its core as our Sun does, or a brown dwarf, an object like a star yet without the mass to sustain nuclear reactions in its core. The researchers were unable to confirm which category the star fits into due to the nature of the observations and the margin of error.

With support from the National Science Foundation (NSF), Bennett has been one of the pioneers in using gravitational microlensing for detecting low mass planets. He has been working with collaborators around the world to find a number of planets that are ever closer in size to our own.

For the most recent discovery, the research collaborators took advantage of two international telescope collaborations: Microlensing Observations in Astrophysics (MOA), which includes Bennett, and the Optical Gravitational Lensing Experiment (OGLE).

Researchers in New Zealand made the initial measurements of the new planet and its star using the new MOA-II telescope at the Mt. John Observatory. The observatory’s MOA-cam3 camera, in one observation, can capture an image of the sky 13 times larger than the area of the full moon. Researchers in Chile made follow-up observations using high angular resolution adaptive optics images at the Very Large Telescope at the European Southern Observatory. Data from the observations was analyzed by scientists around the world hailing from five continents.

“This discovery is very exciting because it implies Earth-mass planets can form around low-mass stars, which are very common,” said Michael Briley, NSF astronomer and the officer who oversees Bennett’s grant. “It is another important step in the search for terrestrial planets in the habitable zones of other stars, and it would not have been possible without the international collaboration of professional and amateur astronomers devoted to measuring these signals.”

A paper describing this result has been accepted for publication in the Astrophysical Journal and is scheduled for publication in the Sept. 1 edition.

Ice Under Phoenix

Take a look at this image sent back from the Phoenix lander. On Friday, Phoenix scientist Ray Arvidson said there may be ice directly under the Phoenix lander, exposed in the blast zone by the retrorockets used for Phoenix’s soft landing. Friday’s image showed a small portion of the exposed area that looks brighter and smoother than the surrounding soil. On Saturday, Sol 5 for Phoenix on Mars, a new image shows a greater portion of the area under the lander. Scientists say the abundance of excavated smooth and level surfaces adds evidence to a hypothesis that the underlying material is an ice table covered by a thin blanket of soil. This is just what the Phoenix mission was hoping to find, and how incredible to land directly over your goal.

The bright-looking surface material in the center, where the image is partly overexposed, may not be inherently brighter than the foreground material in shadow. But the scientists are calling this area “Holy Cow.” Reportedly (via Emily at the Planetary Society) that’s exactly the phrase exclaimed when this image was returned. More pictures of this feature will be imaged using different exposures in an effort to determine if this really is ice.

The other interesting aspect of this image is that the retrorocket nozzles are visible right at the top of the image.

Mars lander prepares for 3-month digging mission

The one snag on the lander occurred when the protective sheath around the trench-digging robotic arm failed to unwrap all the way after touchdown and now covers the arm’s elbow joint.

Deputy project scientist Deborah Bass of NASA’s Jet Propulsion Laboratory said scientists still planned to start the process of unstowing the arm Tuesday, but it could take an extra day to fully stretch the arm.

“I would say this is an inconvenience,” Bass said.

Since landing on Mars on Sunday, Phoenix has delighted scientists with the first-ever peek of the planet’s unexplored northern latitudes. The terrain where Phoenix set its three legs is relatively flat with polygon-shaped patterns in the ground likely caused by the expansion and contraction of underground ice.

Phoenix is on a three-month mission to excavate the soil using its 8-foot-long robotic arm to reach the ice believed to be buried inches to a foot deep.

The lander will study whether the landing site could have supported primitive life. Among the things it will look for is whether the ice melted in Mars’ history and whether the soil samples contain traces of organic compounds, one of the building blocks of life.

On Monday, NASA released a black-and-white image captured during Phoenix’s descent by the Mars Reconnaissance Orbiter, which had a bird’s-eye view of the lander coming down on its parachute. It’s the first time a spacecraft had taken an image of another craft during landing.

Alfred McEwen of the University of Arizona’s Lunar and Planetary Laboratory said the camera aboard Reconnaissance Orbiter has taken many unique pictures of Mars, but “this one’s really unique.”

“It’s the first time any camera has imaged an actual descent through an atmosphere of another planet,” said McEwen, who operates the orbiter’s camera. “This will be on my Top Ten list.”

The $420 million Phoenix mission is led by University of Arizona, Tucson and managed by JPL.

Stephen Hawking calls for Moon and Mars colonies

Stephen Hawking called for a massive investment in establishing colonies on the Moon and Mars in a lecture in honour of NASA’s 50th anniversary. He argued that the world should devote about 10 times as much as NASA’s current budget – or 0.25% of the world’s financial resources – to space.

The renowned University of Cambridge physicist has previously spoken in favour of colonising space as an insurance policy against the possibility of humanity being wiped out by catastrophes like nuclear war and

climate change. He argues that humanity should eventually expand to other solar systems.

But in a speech in Washington, DC, US, delivered in honour of NASA’s 50th anniversary in 2008, Hawking

focused on near-term possibilities, backing the space agency’s goals of returning astronauts to the Moon by 2020 and sending humans to Mars soon after that.

The Moon is a good place to start because it is “close by and relatively easy to reach”, Hawking said. “The

Moon could be a base for travel to the rest of the solar system,” he added. Mars would be “the obvious next target”, with its abundant supplies of frozen water, and the tantalising possibility that life may have been present there in the past.

Some space experts have recently called for NASA to send astronauts to a near-Earth asteroid instead of the Moon as a next step.

Hawking did not mention the idea, but said that any long-term site for a human base should have a significant gravity field. That’s because long missions in microgravity lead to health issues such as bone loss.

Boldly go

He also called for an acceleration of NASA’s plans for human landings on Mars, which one NASA study suggested could be done in the early 2030s. “A goal of a base on the Moon by 2020 and of a manned landing on Mars by 2025 would reignite the space programme and give it a sense of purpose in the same way that President Kennedy’s Moon target did in the 1960s,” he said.

Hawking made a pitch for human space exploration, rather than just sending robots to explore space, a position taken by Nobel laureate Steven Weinberg, among others.

“Robotic missions are much cheaper and may provide more scientific information, but they don’t catch the public imagination in the same way, and they don’t spread the human race into space, which I’m arguing should be our long-term strategy,” Hawking said. “If the human race is to continue for another million years, we will have to boldly go where no one has gone before.”

Interstellar travel

Eventually, Hawking said, humanity should try to expand to Earth-like planets around other stars.

No such planets are known so far. But even if only 1% of the 1000 or so stars within 30 light years of Earth has an Earth-size planet at the right distance from its star for liquid water to exist, that would make for 10 such planets in our solar system’s neighbourhood, he said.

“We cannot envision visiting them with current technology, but we should make interstellar travel a long-term aim,” he said. “By long term, I mean over the next 200 to 500 years.”

Humanity can afford to battle earthly problems like climate change and still have plenty of resources left over for colonising space, he said.

Intelligent life

“Even if we were to increase the international [space exploration] budget 20 times to make a serious effort to go into space, it would only be a small fraction of world GDP,” he said. GDP, or Gross Domestic Product, is a measure of a country’s economic activity.

Hawking argued that the world can afford 0.25% of its collective GDP to devote to space colonisation. “Isn’t our future worth a quarter of a percent?” he asked.

The physicist also speculated on the reasons that SETI (Search for Extra-Terrestrial Intelligence) projects have not yet detected any alien civilisations.

He offered three possibilities: that life of any kind is very rare in the universe; that simple life forms are common, but intelligent life rare; or that intelligent life tends to quickly destroy itself.

“Personally, I favour the second possibility – that primitive life is relatively common, but that intelligent life is very rare,” he said. “Some would say it has yet to occur on Earth.”

Clay tablet holds clue to asteroid mystery

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British scientists have deciphered a mysterious ancient clay tablet and believe they have solved a riddle over a giant asteroid impact more than 5,000 years ago.

Geologists have long puzzled over the shape of the land close to the town of Köfels in the Austrian Alps, but were unable to prove it had been caused by an asteroid.

Now researchers say their translation of symbols on a star map from an ancient civilisation includes notes on a mile-wide asteroid that later hit Earth – which could have caused tens of thousands of deaths.

The circular clay tablet was discovered 150 years ago by Sir Austen Henry Layard, a leading Victorian archaeologist, in the remains of the royal palace at Nineveh, capital of ancient Assyria, in what is now Iraq.

The tablet, on display at the British Museum, shows drawings of constellations and pictogram-based text known as cuneiform – used by the Sumerians, the earliest known civilisation in the world.

A historian from Azerbaijan, who believes humans originally came to Earth from another planet, has interpreted it as a description of the arrival of a spaceship. More mainstream academics have failed to decipher its meaning.

Now Alan Bond, the managing director of a space propulsion company, Reaction Engines, and Mark Hempsell, a senior lecturer in astronautics at Bristol University, have cracked the cuneiform code and used a computer programme that can reconstruct the night sky thousands of years ago to provide a new explanation.

They believe their calculations prove the tablet – a copy made by an Assyrian scribe around 700 BC – is a Sumerian astronomer’s notebook recording events in the sky on June 29, 3123 BC.

The pair say its symbols include a note of the trajectory of a large object travelling across the constellation of Pisces which, to within one degree, is consistent with an impact at Köfels.

Mr Hempsell said: “All previous work has drawn a blank on what the tablet is about.

 

“It is such a big jigsaw and the pieces we have found fit together so well that I think we have a definitive proof.”

The Köfels site was originally interpreted as an asteroid impact, however the lack of an obvious impact crater led modern geologists to believe it to be simply a giant landslide.

However, the Bond-Hempsell theory, outlined in their book published today, A Sumerian Observation of the Köfels Impact Event, suggests that the asteroid left no crater because it clipped a mountain and turned into a fireball.

Mr Hempsell said: “The ground heating, though very short, would be enough to ignite any flammable material, including human hair and clothes.

“It is probable more people died under the plume than in the Alps due to the impact blast.”

He added that extreme changes caused to rock and other substances at the site had previously led to the Köfels impact being erroneously dated to around 8,000 years ago.

Mixed signals from NASA about fate of Mars rover

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NASA sent conflicting signals Monday evening about what an official told CNN is a planned $4 million budget cut in NASA’s Mars Exploration Rover program.

Initially the Rover program’s principle investigator, Steve Squyres, said one of two vehicles operating on the planet will be suspended because of the cut. He said he learned he would have to trim $4 million from the program’s $20 million budget.

He said the move would probably force the rover Spirit into hibernation.

But, he said, the rover could be reactivated if funding is later restored. Squyres also said the cuts would mean layoffs among a staff of 300 scientists who operate and analyze the rovers.

But shortly after CNN.com published the story, NASA administrator Michael Griffin said the agency will not shut down one of the two Mars rovers, according to spokesman Bob Jacobs.

“There is a process that has to be followed for any mission to be canceled and the cancellation of the Mars Exploration Rovers is not under consideration,” Jacobs said. “There is an ongoing budget review within the agency’s Mars exploration program. However, shutting down of one of the rovers is not an option.”

NASA headquarters spokesman Dwayne Brown confirmed the budget directive had been issued. The cut’s purpose is to offset cost overruns with the Mars Science Laboratory, a rover set to launch next year, he said.

Spirit was designed, along with its twin, Opportunity, to be a robotic geologist. The rovers have examined Martian rocks and soil, looking for telltale signs of water.

Opportunity hit pay dirt when it found evidence that salty sea once stood in the area now called Meridiani Planum.

NASA spent $800 million to build and launch Spirit and Opportunity to Mars. They landed about three weeks apart in January 2004, on opposite sides of the planet. Both were designed for 90-day missions but are still operating more than four years later.

Squyres also said he has been told to expect an $8 million budget cut in fiscal year 2009.

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