Pasadena, Calif. -- An odd, six-sided, honeycomb-shaped feature circling the entire north pole of Saturn has captured the interest of scientists with NASA's Cassini mission. NASA's Voyager 1 and 2 spacecraft imaged the feature over two decades ago. The fact that it has appeared in Cassini images indicates that it is a long-lived feature. A second hexagon, significantly darker than the brighter historical feature, is also visible in the Cassini pictures. The spacecraft's visual and infrared mapping spectrometer is the first instrument to capture the entire hexagon feature in one image. Image right: This nighttime view of Saturn's north pole shows a bizarre six-sided hexagon feature encircling the entire north pole. The red color indicates the amount of 5-micron wavelength radiation, or heat, generated in the warm interior of Saturn that escapes the planet. Image credit: NASA/JPL/University of Arizona "This is a very strange feature, lying in a precise geometric fashion with six nearly equally straight sides," said Kevin Baines, atmospheric expert and member of Cassini's visual and infrared mapping spectrometer team at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We've never seen anything like this on any other planet. Indeed, Saturn's thick atmosphere where circularly-shaped waves and convective cells dominate is perhaps the last place you'd expect to see such a six-sided geometric figure, yet there it is." The hexagon is similar to Earth's polar vortex, which has winds blowing in a circular pattern around the polar region.  On Saturn, the vortex has a hexagonal rather than circular shape. The hexagon is nearly 25,000 kilometers (15,000 miles) across. Nearly four Earths could fit inside it. The new images taken in thermal-infrared light show the hexagon extends much deeper down into the atmosphere than previously expected, some 100 kilometers (60 miles) below the cloud tops. A system of clouds lies within the hexagon. The clouds appear to be whipping around the hexagon like cars on a racetrack. "It's amazing to see such striking differences on opposite ends of Saturn's poles," said Bob Brown, team leader of the Cassini visual and infrared mapping spectrometer, University of Arizona, Tucson. "At the south pole we have what appears to be a hurricane with a giant eye, and at the north pole of Saturn we have this geometric feature, which is completely different." Image left: This nighttime movie of the depths of the north pole of Saturn reveals a dynamic, active planet lurking underneath the ubiquitous cover of upper-level hazes. Image credit: NASA/JPL/University of Arizona The Saturn north pole hexagon has not been visible to Cassini's visual cameras, because it's winter in that area, so the hexagon is under the cover of the long polar night, which lasts about 15 years. The infrared mapping spectrometer can image Saturn in both daytime and nighttime conditions and see deep inside. It imaged the feature with thermal wavelengths near 5 microns (seven times the wavelength visible to the human eye) during a 12-day period beginning on Oct. 30, 2006. As winter wanes over the next two years, the feature may become visible to the visual cameras. Based on the new images and more information on the depth of the feature, scientists think it is not linked to Saturn's radio emissions or to auroral activity, as once contemplated, even though Saturn's northern aurora lies nearly overhead. Image right: Another view of the bizarre six-sided feature encircling the north pole of Saturn. Image credit: NASA/JPL/University of Arizona The hexagon appears to have remained fixed with Saturn's rotation rate and axis since first glimpsed by Voyager 26 years ago. The actual rotation rate of Saturn is still uncertain. "Once we understand its dynamical nature, this long-lived, deep-seated polar hexagon may give us a clue to the true rotation rate of the deep atmosphere and perhaps the interior," added Baines. The hexagon images and movie, including the north polar auroras are available at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov and http://wwwvims.lpl.arizona.edu . The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The Visual and Infrared Mapping Spectrometer team is based at the University of Arizona.

This composite image at infrared wavelengths was obtained using the Gemini North laser guide star system in conjunction with the ALTAIR adaptive optics system and the NIRI near-infrared imager. The image shows the Orion "bullets" as blue features and represents the light emitted by hot iron gas. The light from the wakes, shown in orange, is from excited hydrogen gas. Gemini Observatory

March 22, 2007 An image released today by the Gemini Observatory brings into focus a new and remarkably detailed view of supersonic "bullets" of gas and the wakes created as they pierce through clouds of molecular hydrogen in the Orion Nebula. The image was made possible with new laser guide star adaptive optics technology that corrects in real time for image distortions caused by Earth's atmosphere. The Orion Nebula is a star-forming region located relatively near to us, about 1,500 light-years away. It's a young stellar nursery and shows many unusual features related to the effect of massive stars on the dense birth environment of gas and dust. The Orion bullets were first seen in a visible-light image in 1983. By 1992, images taken at infrared wavelengths led astronomers to conclude that these clumps of gas were ejected from deep within the nebula following an unknown violent event connected with the recent formation of a cluster of massive stars there. The bullets are speeding outward from the cloud at up to 250 miles (400 kilometers) per second. This is more than a thousand times faster than the speed of sound. The name "bullet" is somewhat misleading since these objects are truly gigantic. The typical size of one of the bullet tips is about ten times the size of Pluto's orbit around the Sun. The wakes shown in the image about are about a fifth of a light- year long. Clouds of iron atoms at the tip of each bullet glow brightly (blue in the Gemini image) as they are shock-heated by friction to around 9,000º Fahrenheit (5000º Celsius). Molecular hydrogen, which makes up the bulk of both the bullets and the surrounding gas cloud, is destroyed at the tips by the violent collisions between the high-speed bullets and the surrounding cloud. On the trailing edges of the bullets, however, the hydrogen molecules are not destroyed, but instead are heated to about 4000ºF (2000ºC). As the bullets plow through the clouds they leave behind distinctive tubular wakes (colored orange in the Gemini image). These wakes shine like bullet tracers due to the heated molecular hydrogen gas. "What I find stunning about the new image is the detail it shows, which was blurred out in any previous studies, revealing the structure of the bullets and their trailing wakes as they run into the surrounding molecular cloud," said Michael Burton of the University of New South Wales who, along with the late David Allen (Anglo-Australian Observatory) were the first to suggest the origin of these spectacular bullets 15 years ago. "This level of precision will allow the evolution of the system to be followed over the next few years, for small changes in the structures are expected from year to year as the bullets continue their outward motion." The bullets are relatively young, with their ages estimated to be less than a thousand years since ejection. The new Gemini adaptive optics image shows them in near-infrared light in a combination of three images using different filters. The blue features in the Gemini image correspond to the shocked regions where the iron is fluorescing. The orange regions are the glowing hydrogen molecules in the bullet's wakes. In this image, the wakes ("fingers") behind each of the iron-gas bullets are resolved into filaments for the first time ever. These might well be the actual sheaths enclosing the shock waves created as the bullets travel through the cloud. The exceptional resolution of the new image was made possible by adaptive optics technology in place at Gemini Observatory. With a laser guide star as a reference and a rapidly deformable mirror for real-time correction, astronomers can compensate for most of the atmospheric distortions that blur the near-infrared image of a star whose light reaches the telescope's primary mirror. The system deploys a yellow/orange solid-state sodium laser that produces the artificial guide star by exciting and causing a small column of sodium gas about 56 miles (90 km) up in our atmosphere to glow. The artificial star it creates becomes a reference star for the adaptive optics system and allows it to determine how the atmosphere distorts the incoming near-infrared starlight.

WASHINGTON (Jan. 7) - Two NASA space probes that visited Mars 30 years ago may have stumbled upon alien microbes on the Red Planet and inadvertently killed them, a scientist theorizes in a paper released Sunday.

 

 

The problem was the Viking space probes of 1976-77 were looking for the wrong kind of life and didn't recognize it, the researcher said in a paper presented at a meeting of the American Astronomical Society in Seattle.

This new report, based on a more expansive view of where life can take root, may have NASA looking for a different type of Martian life form when its next Mars spacecraft is launched later this year, one of the space agency's top scientists told The Associated Press.

Last month, scientists excitedly reported that new photographs of Mars showed geologic changes that suggest water occasionally flows there - the most tantalizing sign that Mars is hospitable to life.

In the '70s, the Viking mission found no signs of life. But it was looking for Earth-like life, in which salt water is the internal liquid of living cells. Given the cold dry conditions of Mars, that life could have evolved on Mars with the key internal fluid consisting of a mix of water and hydrogen peroxide, said Dirk Schulze-Makuch, author of the new research.

That's because a water-hydrogen peroxide mix stays liquid at very low temperatures (-68 degrees Fahrenheit), doesn't destroy cells when it freezes, and can suck scarce water vapor out of the air.

The Viking experiments of the '70s wouldn't have noticed alien hydrogen peroxide-based life and, in fact, would have killed it by drowning and overheating the microbes, said Schulze-Makuch, a geology professor at Washington State University.

One Viking experiment seeking life on Mars poured water on soil. That would have essentially drowned hydrogen peroxide-based life, Schulze-Makuch said. A different experiment heated the soil to see if something would happen, but that would have baked Martian microbes, he said.

"The problem was that they didn't have any clue about the environment on Mars at that time," Schulze-Makuch said. "This kind of adaptation makes sense from a biochemical viewpoint."

 

 

January 23, 2007: If you stare at the Moon long enough, you start seeing things. "82 things to be exact," says Bill Cooke, leader of NASA's Meteoroid Environment Group. That's how many "transient phenomena" the group has video-taped since they started monitoring the night side of the Moon in Nov. 2005.

"In 107 hours of observing, we've tallied 20 lunar meteors + at least 60 Earth-orbiting satellites + one airplane + one terrestrial meteor = 82 in all."

Right: The NASA Meteoroid Environment Group's lunar observatory at the Marshall Space Flight Center in Huntsville, Alabama. Inset is one of two 14-inch telescopes simultaneously trained on the Moon during the group's observing sessions. [larger image]

This is the first systematic count of lunar night-side phenomena. "It gives astronomers an idea of what to expect when they undertake a lunar monitoring program from Earth."

Cooke's prime target is lunar meteors--flashes of light that occur when meteoroids hit the Moon's surface: video. "Of the 20 lunar meteors we've seen so far, about half come from well-known meteor showers such as the Leonids and Geminids. The other half are random meteoroids that take us completely by surprise." NASA is preparing to send astronauts back to the Moon and the agency is understandably interested in how often this happens.

"Everything else we've seen is just a coincidence, something flying in front of the Moon while we happen to be watching." Leading this category are Earth-orbiting satellites and pieces of space debris. This Orbcomm A4 communications satellite is a typical example:

Above: An Orbcomm communication satellite passes in front of the Moon on Nov. 17, 2006: video.

NORAD tracks more than 10,000 Earth-orbiting objects wider than 10 cm. "Some of them are bound to cross in front of the Moon while we're watching," he says. Objects like Orbcomm are easy to identify as satellites. Tumbling space debris, on the other hand, can be trickier: "A sudden glint of sunlight from a flat surface looks an awful lot like a lunar meteor flash," he explains. "So we have to be very careful. When we see a flash of light on the Moon, we always double-check that there was no piece of space junk passing by at that exact moment."

01.24.07

This story is courtesy the European Space Agency A pair of rare celestial alignments that occurred in November 2003 helped an international team of astronomers investigate the far-off world of Titan. In particular, the alignments helped validate the atmospheric model used to design the entry trajectory for ESA's Huygens probe. Now the unique results are helping to place the descent of Huygens in a global context, and to investigate the upper layers of Titan's atmosphere. Occasionally Titan passes directly in front of a distant star. When it does so, the light from the star is blocked out. Because Titan has a thick atmosphere, the light does not 'turn off' straight away. Instead, it drops gradually as the blankets of atmosphere slide in front of the star. The way the light drops tells astronomers about the atmosphere of Titan. Image right: Light curve during Titan occultation event. Image credit: ESA. Image by C.Carreau + Full image and caption By pure chance on 14 November 2003, fourteen months before Huygens' historic descent through Titan's atmosphere, Titan passed in front of two stars, just seven and a half hours apart. Bruno Sicardy, Observatoire de Paris, France, organised expeditions to record the occultations, as such events are called. The first occultation was visible just after midnight from the Indian Ocean and the southern half of Africa. The second could be seen from Western Europe, the Atlantic Ocean, Northern and Central Americas. Teams of astronomers set up along the occultation tracks. Sicardy was looking for one observation in particular. "Titan's atmosphere acts like a lens, so at the very middle of the occultation, a bright flash occurs," explains Sicardy. If Titan's atmosphere were a perfectly uniform layer, the central flash would be a pinprick of light, visible only at the very centre of the planet's shadow. However, comparing the results from many telescopes, Sicardy found that the central flash fell across the Earth in a triangular shape. "It is like the light falling through a glass of water and making bright patterns on the table. The focused light is not perfectly round because the glass is not a perfect lens," says Sicardy. Analysing the shape of the flash showed that Titan's atmosphere was flattened at the north pole. This was because at the time of the occultation, Titan's south pole was tilted towards the Sun. This warmed the atmosphere there, causing it to rise and move towards the north of the moon, where the atmosphere cooled and sank towards the surface. There was one other key discovery that the occultation data allowed Sicardy and his team to make. A fast moving, high altitude wind (above 200 kilometres) was blowing around Titan at latitude of 50 degrees north. They estimated that it was moving at 200 metres per second (or 720 kilometres per hour) and would encircle the planet in less than one terrestrial day. "It is like the jet stream on Earth," says Sicardy, "Furthermore, we told the Huygens team to expect some bumps near 510 km altitude, due to a narrow and sudden temperature variation." Indeed, Huygens was jolted by exactly such a layer during its 14 January 2005 entry. "A temperature inversion was indeed detected by the accelerometers during entry at this very altitude" says Jean-Pierre Lebreton, Huygens project scientist. The work does not stop there. Even though the Huygens descent took place almost two years ago, the understanding of its data continues to provide key insights into Titan. Note to Editors The findings appear in the article "The two Titan stellar occultations of 14 November 2003", by Bruno Sicardy et al., published in Journal of geophysical research (Vol. 111, E11S91, doi:10.1029/2005JE002624, 2006).

January 8th, 2007

The map was made using the Hubble Space Telescope’s largest survey of the Universe, the Cosmic Evolution Survey. An international team of 70 astronomers measured the shapes of 500,000 galaxies in this survey, looking for subtle distortions. These distortions are due to the gravitational warping of intervening dark matter. The more distortions, the more dark matter in a region.

Their research suggest that dark matter started out evenly distributed across the Universe, and then began to pull together and clump into long filaments. And at the heart of these filaments, we see the largest concentrations of regular matter.

By Michael Griffin
Administrator
National Aeronautics and Space Administration

As NASA resumes flights of the space shuttle to finish building the International Space Station, many are questioning whether the project – the most complex construction feat ever undertaken – is worth the risk and expense.

Image above: Artist's concept of the Orion crew vehicle in lunar orbit. Credit: Lockheed Martin Corp.

I have been asked, and asked myself, this question many times during my career, particularly when the United States lacked a plan to go beyond the space station to other destinations in the solar system.

The issue was addressed eloquently in the report of the Columbia Accident Investigation Board, which examined the 2003 loss of the shuttle and its crew. That report pointed out that for the foreseeable future, space travel is going to be expensive, difficult and dangerous. But, for the United States, it is strategic. It is part of what makes us a great nation. And the report declared that if we are going to send humans into space, the goals ought to be worthy of the cost, the risk and the difficulty. A human spaceflight program with no plan to send people anywhere beyond the orbiting space station certainly did not meet that standard.

President Bush responded to the Columbia report. The administration looked at where we had been in space and concluded that we needed to do more, to go further. The result was the Vision for Space Exploration, announced nearly three years ago, which commits the United States to using the shuttle to complete the space station, then retiring the shuttle and building a new generation of spacecraft to venture out into the solar system. Congress has ratified that position with an overwhelming bipartisan majority, making the Vision for Space Exploration the law of the land.

"I believe America should look to its future – and consider what that future will look like if we choose not to be a spacefaring nation."

--NASA Administrator Michael Griffin

Today, NASA is moving forward with a new focus for the manned space program: to go out beyond Earth orbit for purposes of human exploration and scientific discovery. And the International Space Station is now a stepping stone on the way, rather than being the end of the line.

On the space station, we will learn how to live and work in space. We will learn how to build hardware that can survive and function for the years required to make the round-trip voyage from Earth to Mars.

If humans are indeed going to go to Mars, if we're going to go beyond, we have to learn how to live on other planetary surfaces, to use what we find there and bend it to our will, just as the Pilgrims did when they came to what is now New England – where half of them died during that first frigid winter in 1620. There was a reason their celebration was called "Thanksgiving."

The Pilgrims were only a few thousand miles from home, and they were accomplished farmers and artisans. And yet, when they came to an unfamiliar land, they didn’t know how to survive in its harsh environment. They didn’t know what food would grow and what wouldn’t. They didn’t know what they could eat and what they couldn't.

Image above: The International Space Station, the most complex construction feat ever undertaken, will teach us how to live and work in space.

The Pilgrims had to learn to survive in a strange new place across a vast ocean. If we are to become a spacefaring nation, the next generation of explorers is going to have to learn how to survive in other forbidding, faraway places across the vastness of space. The moon is a crucially important stepping stone along that path – an alien world, yet one that is only a three-day journey from Earth.

Using the space station and building an outpost on the moon to prepare for the trip to Mars are critical milestones in America's quest to become a truly spacefaring nation. I think that we should want that. I want that. I want it for the American people, for my grandchildren, for my great-grandchildren.

Throughout history, the great nations have been the ones at the forefront of the frontiers of their time. Britain became great in the 17th century through its exploration and mastery of the seas. America's greatness in the 20th century stemmed largely from its mastery of the air. For the next generations, the frontier will be space.

Other countries will explore the cosmos, whether the United States does or not. And those will be Earth's great nations in the years and centuries to come. I believe America should look to its future – and consider what that future will look like if we choose not to be a spacefaring nation.

March 9, 2007: Andy Cheng has seen it all. The scientist from Johns Hopkins' Applied Physics Lab has worked on the Galileo mission to Jupiter, the Cassini mission to Saturn, the NEAR mission to asteroid 433 Eros and many others during his decades-long career. Alien vistas are old hat to him.

But even he was amazed when he laid eyes on this photo of Io's Tvashtar volcano, taken Feb. 28th by the New Horizons spacecraft:

Above: A volcanic eruption on Io photographed by New Horizons on Feb. 28, 2007.

Omigod! I can't believe it. "That was my first reaction," says Cheng. "The LORRI image of the Tvashtar plume is the best and most detailed plume image that any of us -- including longtime Jupiter experts -- have ever seen."

LORRI is an 8-inch telescope onboard New Horizons, NASA's Pluto-bound spacecraft. "The telescope was designed to take high-resolution pictures of Pluto and its moons when New Horizons reaches the outer solar system in 2015," explains Cheng, the principal investigator for LORRI, which is short for Long Range Reconnaissance Imager.

Last week New Horizons flew past Jupiter for a quick velocity boost, and "this gave us an opportunity to take some pictures," he says. Cheng and colleagues trained the telescope on Jupiter's moons Io, Europa, Callisto and Ganymede and on Jupiter itself. Many of the pictures are stunning: gallery.

"Future LORRI images of Pluto and Charon will have even more detail and higher resolution, because New Horizons will bring us at least a thousand times closer than we came to Io," notes Cheng. Of course, no one has any idea what LORRI will see, because Pluto has never been visited by a space probe. "That's why we're going."

Catching a volcano blowing its top on Io isn't really a big surprise, notes Cheng. "Io is in a constant state of eruption."

To understand why, he suggests, dig a paperclip out of your desk drawer. Flex the clip rapidly back and forth many times, and touch the flexure. Careful! It's hot. The combination of flexing + internal friction heats the clip to surprisingly high temperatures.

The same thing happens to Io. Gravitational forces exerted on Io by Jupiter and the other large moons raise tidal bulges in Io's solid crust 30 meters high. This flexing action, like the flexing of a paperclip, makes Io's interior molten hot and, as a result, the moon has hundreds of active volcanoes.

 

"We were actually hoping to catch a different volcanoPrometheus," says Cheng. Prometheus is an old and reliable volcano on Io which has been photographed many times before by Voyager and Galileo. It appears in the New Horizons photo, too; "It's the little mushroom-shaped plume at 9 o'clock," he points out.

Tvashtar's plume dwarfed grand old Prometheus, rising 180 miles (290 km) above Io's surface. (For comparison, volcanoes on Earth spew their gas and dust just a few miles high.) "The patchy and filamentous structure seen in the Tvashtar plume suggests to me that condensation from gas to solid particulates is occurring," he says. In other words, the gas could be crystallizing in the cold space above Io to form a kind of sulfurous snow.

Volcanoes spewing snow? It is an alien world.