NASA Chooses Three Finalists for Future Space Science Mission to Venus, an Asteroid or the Moon

NASA has selected three proposals as candidates for the agency's next space venture to another celestial body in our solar system. The final project selected in mid-2011 may provide a better understanding of Earth's formation or perhaps the origin of life on our planet.

The proposed missions would probe the atmosphere and crust of Venus; return a piece of a near-Earth asteroid for analysis; or drop a robotic lander into a basin at the moon's south pole to return lunar rocks back to Earth for study.

NASA will select one proposal for full development after detailed mission concept studies are completed and reviewed. The studies begin during 2010, and the selected mission must be ready for launch no later than Dec. 30, 2018. Mission cost, excluding the launch vehicle, is limited to $650 million.

"These are projects that inspire and excite young scientists, engineers and the public," said Ed Weiler, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. "These three proposals provide the best science value among eight submitted to NASA this year."

Each proposal team initially will receive approximately $3.3 million in 2010 to conduct a 12-month mission concept study that focuses on implementation feasibility, cost, management and technical plans. Studies also will include plans for educational outreach and small business opportunities.

SOHO EIT 195 Latest Image

Cassini Spacecraft to Monitor North Pole on Titan

Though there are no plans to investigate whether Saturn's moon Titan has a Santa Claus, NASA's Cassini will zoom close to Titan's north pole this weekend.

The flyby, which brings Cassini to within about 960 kilometers (600 miles) of the Titan surface at 82 degrees north latitude, will take place the evening of Dec. 27 Pacific time, or shortly after midnight Universal Time on Dec. 28.

The encounter will enable scientists to gather more detail on how the lake-dotted north polar region of Titan changes with the seasons. Scientists will be using high-resolution radar to scan the large and numerous lakes in the north polar region for shape-shifting in size and depth. The ion and neutral mass spectrometer team will take baseline measurements of the atmosphere to compare with the moon's south polar region when Cassini flies by that area on Jan. 12. Cassini will also be collecting images for a mosaic of a bright region called Adiri, where the Huygens probe landed nearly five years ago.

Cassini will have released the Huygens probe exactly five years and three days before this latest flyby. Huygens began its journey down to Titan on the evening of Dec. 24, 2004 California time, or early Dec. 25 Universal Time, and reached the surface Jan. 14, 2005.

Cassini last flew by Titan on Dec. 11, 2009 California time, or Dec. 12 Universal Time. Although this latest flyby is dubbed "T64," planning changes early in the orbital tour have made this the 65th targeted flyby of Titan.

Cassini Holiday Movies Showcase Dance of Saturn's Moons

Like sugar plum fairies in "The Nutcracker," the moons of Saturn performed a celestial ballet before the eyes of NASA's Cassini spacecraft. New movies frame the moons' silent dance against the majestic sweep of the planet's rings and show as many as four moons gliding around one another.

The new video can be found at http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org.

To celebrate the holidays, the Cassini imaging team has created a video collection of "mutual events," which occur when one moon passes in front of another, as seen from the spacecraft. Imaging scientists use mutual event observations to refine their understanding of the dynamics of Saturn's moons. Digital image processing has enabled scientists to turn these routine observations into breathtaking displays of celestial motion. The original images were captured between Aug. 27 and Nov. 8, 2009.

In one scene that synthesizes 12 images taken over the span of 19 minutes, Rhea skates in front of Janus, as Mimas and Pandora slide across the screen in the opposite direction. While the dance appears leisurely on screen, Rhea actually orbits Saturn at a speed of about 8 kilometers per second (18,000 mph). The other moons are hurtling around the planet even faster. Mimas averages about 14 kilometers per second (31,000 mph), and Janus and Pandora travel at about 16 kilometers per second (36,000 mph).

"As yet another year in Saturn orbit draws to a close, these wondrous movies of an alien place clear across the solar system remind us how fortunate we are to be engaged in this magnificent exploratory expedition," said Carolyn Porco, Cassini imaging team leader at the Space Science Institute in Boulder, Colo.

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 mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

Keck Telescopes Gaze into Young Star's "Life Zone"

The inner regions of young planet-forming disks offer information about how worlds like Earth form, but not a single telescope in the world can see them. Yet, for the first time, astronomers using the W. M. Keck Observatory in Hawaii have measured the properties of a young solar system at distances closer to the star than Venus is from our sun.

"When it comes to building rocky planets like our own, the innermost part of the disk is where the action is," said team member William Danchi at NASA's Goddard Space Flight Center in Greenbelt, Md. Planets forming in a star's inner disk may orbit within its "habitable zone," where conditions could potentially support the development of life.

To achieve the feat, the team used the Keck Interferometer to combine infrared light gathered by both of the observatory's twin 10-meter telescopes, which are separated by 85 meters. The double-barreled approach gives astronomers the effective resolution of a single 85-meter telescope -- several times larger than any now planned.

"Nothing else in the world provides us with the types of measurements the Keck Interferometer does," said Wesley Traub at Caltech's Jet Propulsion Laboratory in Pasadena, Calif. "In effect, it's a zoom lens for the Keck telescopes."

In August 2008, the team -- led by Sam Ragland of Keck Observatory and including astronomers from the California Institute of Technology and the National Optical Astronomical Observatory -- observed a Young Stellar Object (YSO) known as MWC 419. The blue, B-type star has several times the sun's mass and lies about 2,100 light-years away in the constellation Cassiopeia. With an age less than ten million years, MWC 419 ranks as a stellar kindergartener.

The team also employed a new near-infrared camera designed to image wavelengths in the so-called L band from 3.5 to 4.1 micrometers. "This unique infrared capability adds a new dimension to the Keck Interferometer in probing the density and temperature of planet-forming regions around YSO disks. This wavelength region is relatively unexplored," Ragland explained. "Basically, anything we see through this camera is brand new information."

The increased ability to observe fine detail, coupled with the new camera, let the team measure temperatures in the planet-forming disk to within about 50 million miles of the star. "That's about half of Earth's distance from the sun, and well within the orbit of Venus," Danchi said.

AcrimSat Celebrates 10 Years of Measuring the Sun's Energy

Launched Dec. 20, 1999, the Active Cavity Radiometer Irradiance Monitor Satellite (AcrimSat) monitors the total amount of the sun's energy reaching Earth. It is this energy, called total solar irradiance, that creates the winds, heats the land and drives ocean currents. Some scientists theorize a significant fraction of Earth's warming may be solar in origin due to small increases in the sun's total energy output since the last century. By measuring incoming solar radiation, climatologists are using AcrimSat to improve their predictions of climate change and global warming over the next century.

Colliding Auroras Produce an Explosion of Light

A network of cameras deployed around the Arctic in support of NASA's THEMIS mission has made a startling discovery about the Northern Lights. Sometimes, vast curtains of aurora borealis collide, producing spectacular outbursts of light. Movies of the phenomenon were unveiled at the Fall Meeting of the American Geophysical Union today in San Francisco.

"Our jaws dropped when we saw the movies for the first time," said space scientist Larry Lyons of the University of California-Los Angeles (UCLA), a member of the team that made the discovery. "These outbursts are telling us something very fundamental about the nature of auroras."

The collisions occur on such a vast scale that isolated observers on Earth -- with limited fields of view -- had never noticed them before. It took a network of sensitive cameras spread across thousands of miles to get the big picture.

NASA and the Canadian Space Agency created such a network for THEMIS, short for "Time History of Events and Macroscale Interactions during Substorms." THEMIS consists of five identical probes launched in 2006 to solve a long-standing mystery: Why do auroras occasionally erupt in an explosion of light called a substorm?

Twenty all-sky imagers (ASIs) were deployed across the Alaskan and Canadian Arctic to photograph auroras from below while the spacecraft sampled charged particles and electromagnetic fields from above. Together, the on-ground cameras and spacecraft would see the action from both sides and be able to piece together cause and effect-or so researchers hoped. It seems to have worked.

The breakthrough came earlier this year when UCLA researcher Toshi Nishimura assembled continent-wide movies from the individual ASI cameras. "It can be a little tricky," Nishimura said. "Each camera has its own local weather and lighting conditions, and the auroras are different distances from each camera. I've got to account for these factors for six or more cameras simultaneously to make a coherent, large-scale movie."

Quiet Sun Means Cooling of Earth's Upper Atmosphere

New measurements from a NASA satellite show a dramatic cooling in the upper atmosphere that correlates with the declining phase of the current solar cycle. For the first time, researchers can show a timely link between the Sun and the climate of Earth’s thermosphere, the region above 100 km, an essential step in making accurate predictions of climate change in the high atmosphere.

Scientists from NASA's Langley Research Center and Hampton University in Hampton, Va., and the National Center for Atmospheric Research in Boulder, Colo., presented these results at the fall meeting of the American Geophysical Union in San Francisco from Dec. 14 to 18.

Earth's thermosphere and mesosphere have been the least explored regions of the atmosphere. The NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) mission was developed to explore the Earth’s atmosphere above 60 km altitude and was launched in December 2001. One of four instruments on the TIMED mission, the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, was specifically designed to measure the energy budget of the mesosphere and lower thermosphere. The SABER dataset now covers eight years of data and has already provided some basic insight into the heat budget of the thermosphere on a variety of timescales.

The extent of current solar minimum conditions has created a unique situation for recent SABER datasets, explains Stan Solomon, acting director of the High Altitude Observatory, National Center for Atmospheric Research in Boulder, Colo. The end of solar cycle 23 has offered an opportunity to study the radiative cooling in the thermosphere under exceptionally quiescent conditions.

Sunlight Glint Confirms Liquid in Titan Lake Zone

NASA's Cassini Spacecraft has captured the first flash of sunlight reflected off a lake on Saturn's moon Titan, confirming the presence of liquid on the part of the moon dotted with many large, lake-shaped basins.

Cassini scientists had been looking for the glint, also known as a specular reflection, since the spacecraft began orbiting Saturn in 2004. But Titan's northern hemisphere, which has more lakes than the southern hemisphere, has been veiled in winter darkness. The sun only began to directly illuminate the northern lakes recently as it approached the equinox of August 2009, the start of spring in the northern hemisphere. Titan's hazy atmosphere also blocked out reflections of sunlight in most wavelengths. This serendipitous image was captured on July 8, 2009, using Cassini's visual and infrared mapping spectrometer.



This image will be presented Friday, Dec. 18, at the fall meeting of the American Geophysical Union in San Francisco.

"This one image communicates so much about Titan -- thick atmosphere, surface lakes and an otherworldliness," said Bob Pappalardo, Cassini project scientist, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It's an unsettling combination of strangeness yet similarity to Earth. This picture is one of Cassini's iconic images."

Titan, Saturn's largest moon, has captivated scientists because of its many similarities to Earth. Scientists have theorized for 20 years that Titan's cold surface hosts seas or lakes of liquid hydrocarbons, making it the only other planetary body besides Earth believed to harbor liquid on its surface. While data from Cassini have not indicated any vast seas, they have revealed large lakes near Titan's north and south poles.

NASA Gets Up-Close Look at Far Corner of the Globe

The Arctic remains in the mind a pristine wonderland. The landmasses that jut into the Arctic Circle are covered by tundra and primeval forest; the pole is covered in ice. The whole environment seems detached from human influence entirely. But the scientific record tells a different story.

A months-long airborne campaign in 2008 gave scientists a new look at how everyday human behaviors in Europe, North America and Asia are affecting the Arctic, the most rapidly changing region on Earth and a major regulator of the planet's climate. The data show human fingerprints all over the Arctic in the form of polluted exhaust from factories and smoke from fires often set by human hands. Observations from the ground have long recorded some of this impact, and satellites in low-earth orbit provide a different view, but scientists had not undertaken a detailed, airborne study of this magnitude in years.

The mission provided a new view of how pollution from industrializing Asian countries influences the Arctic. Ground sensors have long detected the regular, low-altitude movement of polluted air masses from Europe to the Arctic. Because of the colder temperatures in the countries of the pollution's origin, the plumes of carbon dioxide, carbon monoxide and other warming-related gases do not rise high in the atmosphere. On the contrary, pollution from warmer regions in Asia has apparently been moving to altitudes too high for ground instruments to observe well. The airborne instruments provided invaluable measurements of the extent of this pollution, said Daniel Jacob, a Harvard University atmospheric scientist and both mission scientist and co-principal investigator for NASA’s Arctic Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission.

"With Asian pollution, there's a relatively warm ocean immediately downwind of a fairly cold continent, so you have interesting storm tracks that lift pollution and transport it at higher altitudes," Jacob said. "It's certainly a much larger influence on Arctic haze than what had been traditionally ascribed."

Now that researchers have had some time to sift through the data collected, Jacob said the value of these observations is coming in to focus. Major airborne campaigns like this are rare, so almost any study of the Arctic atmosphere in coming years will draw on ARCTAS.

Solar Storms and Radiation Exposure on Commercial Flights

Scientists at NASA’s Langley Research Center have completed a first attempt to accurately calculate the level of damaging radiation flight crews and passengers are exposed to on commercial airline flights. The work is an early step toward developing a model to observe radiation exposure for all commercial flights, particularly for pilots and crews who spend their careers airborne and who are at greater risk of developing certain cancers.

The study considered not only everyday radiation emanating from space, but also the additional energy unleashed during a solar storm, which can be profound. NASA scientists say not including geomagnetic effects on solar radiation in modeling radiation exposure could underestimate the dosage by 30 to 300 percent.

Researchers looked at passengers and crew on typical flights from Chicago to Beijing, Chicago to Stockholm and London to New York, during what is known as the Halloween 2003 Storm. These flights were chosen because of their long flight paths near the North Pole, where the Earth’s natural protection from radiation is weakest. Earth’s magnetic field approaches zero above the poles. The Halloween 2003 event was chosen because it was both a large and a complex storm, making it a good test for the model.

The study found that aircrew and passengers during the Chicago to Beijing flight, for example, would have been exposed to about 12 percent of the annual radiation limit recommended by the International Committee on Radiological Protection. But these exposures were greater than on typical flights at lower latitudes, and confirmed the concerns about commercial flights at high latitudes.

“The upshot is that these international flights were right there at that boundary where many of these events can take place, where radiation exposure can be much higher,” said Chris Mertens, senior research scientist at NASA’s Langley Research Center, who is leading the research effort. Mertens will present his latest results at the American Geophysical Union fall meeting in San Francisco on Dec. 16.

A Unique Geography -- and Soot and Dust -- Conspire Against Himalayan Glaciers

So many disparate elements, both natural and man-made, converge in the Himalayas," said William Lau, a climatologist from NASA’s Goddard Space Flight Center in Greenbelt, Md. "There’s no other place in the world that could produce such a powerful atmospheric heat pump," referring to a new hypothesis he’s put forward to explain the rapid retreat of Himalayan glaciers in recent decades.

The Himalayas, home to the tallest mountains on Earth, include more than 110 peaks and stretch 2,500 kilometers (1,550 miles). Bounded to the north by the Tibetan Plateau, to the west by deserts, and to the south by a bowl-like basin teeming with people, the mountains hold 10,000 glaciers.

These massive rivers of ice spill off mountain sides and grind down through creviced valleys. In the spring, when the monsoon carries moist air from the Indian Ocean, the glaciers begin to thaw, replenishing lakes, streams, and some of Asia's mightiest rivers, on which more than a billion people depend.

South of the Himalayas -- which forms the east-west edge of the table-like Tibetan Plateau -- the mountains give way to the Indo-Gangetic plain, one of the most fertile and densely populated areas on Earth. The plain has become a megalopolis of cities including Delhi, Dhaka, Kanpur, and Karachi, as well as a hotspot for air pollution, with a steady supply of industrial soot mixing with ash and other particles in the air.

Hitch A Ride On The Glory Satellite

Want to hitch a ride on NASA's next climate monitoring satellite? Join the Glory mission, which will launch no earlier than Oct. 1, by surfing over to the Send Your Name Around the Earth web page. Names will be recorded on a microchip built into the satellite, and you will get a printable certificate from NASA acknowledging your participation. There are already 225,155 names on the chip, but there's plenty more room. (You cannot submit your name more than once.)

The website is located at: http://polls.nasa.gov/utilities/sendtospace/jsp/sendName.jsp.

Glory carries two scientific sensors dedicated to understanding the effects of aerosols and the sun's variability on Earth's climate. The Aerosol Polarimetry Sensor will collect information about tiny liquid and solid particles suspended in the atmosphere that absorb or reflect sunlight. The Total Irradiance Monitor will measure the intensity of incoming sunlight which can vary over time.

Reddish Dust and Ice Migration Darken Saturn's Moon Iapetus

New views of Saturn's moon Iapetus accompany papers that detail how reddish dust swept up on the moon's orbit around Saturn and migrating ice can explain the bizarre, yin-yang-patterned surface.

The papers, led by Cassini scientists Tilmann Denk and John Spencer, appeared online in the journal Science on Dec. 10, 2009.

The new image in the left-hand panel of PIA11690 shows the most nearly complete view to date of Iapetus' charcoal-dark leading hemisphere. The right-hand panel, which had been released previously, shows the trailing hemisphere, where wide swaths are covered by bright ice. The new three-panel image PIA11689 uses false-color views in increasing levels of contrast to reveal the reddish dust that overlays the bright-dark pattern. Minimal enhancement was applied to the left panel, with increasing contrast added to the middle and right-hand images.

Geminids Meteor Shower: Nature's 'Holiday Light Show'

The Geminids are one of the best meteor showers of the year and never seem to disappoint observers! Join Bill Cooke of the Meteoroid Environment Office, located at NASA's Marshall Space Flight Center, in a live web chat on Friday, December 11 from 3:00-4:00 EST to learn more about the Geminids meteor shower.

This meteor shower gets the name "Geminids" because it appears to radiate from the constellation Gemini. For the best viewing opportunity, go outside, take a blanket and something hot to drink, lay on your back and look up into the night sky. Best viewing time is between midnight and dawn on December 13-14.

An observer in the Northern hemisphere can start seeing the Geminids meteors as early as December 6, when one meteor every hour or so could be visible. During the next week, rates increase until a peak of 50-80 meteors per hour is attained on the night of December 13-14. The last Geminids are seen on December 18, when an observer might see a rate of one or so every hour.

History of the Geminids

The initial appearance of the Geminids meteor shower came fairly sudden during the 1860s. The first notation of the shower occurred in 1862 at Manchester, England. During the 1870s, observations of the Geminids became more numerous as astronomers realized a new annual shower was active.

The first estimate of the strength of Geminids came in 1877 with an hourly rate given at about 14. Rates increased slightly during the remainder of the 19th century to about 23 an hour. Reported rates continued to increase through most of the 20th century. During the 1900s, rates averaged about 20 per hour. The rates averaged near 50 per hour during the 1930s, 60 per hour during the 1940s and 1950s, 65 per hour during the 1960s and 80 per hour during the 1970s. The rates stayed near 80 per hour during the remainder of that century.

Suzaku Spies Treasure Trove of Intergalactic Metal

Every cook knows the ingredients for making bread: flour, water, yeast, and time. But what chemical elements are in the recipe of our universe?

Most of the ingredients are hydrogen and helium. These cosmic lightweights fill the first two spots on the famous periodic table of the elements.

Less abundant but more familiar to us are the heavier elements, meaning everything listed on the periodic table after hydrogen and helium. These building blocks, such as iron and other metals, can be found in many of the objects in our daily lives, from teddy bears to teapots.

Recently astronomers used the Suzaku orbiting X-ray observatory, operated jointly by NASA and the Japanese space agency, to discover the largest known reservoir of rare metals in the universe.

Suzaku detected the elements chromium and manganese while observing the central region of the Perseus galaxy cluster. The metallic atoms are part of the hot gas, or "intergalactic medium," that lies between galaxies.

"This is the first detection of chromium and manganese from a cluster," says Takayuki Tamura, an astrophysicist at the Japan Aerospace Exploration Agency who led the Perseus study. "Previously, these metals were detected only from stars in the Milky Way or from other galaxies. This is the first detection in intergalactic space."

The cluster gas is extremely hot, so it emits X-ray energy. Suzaku's instruments split the X-ray energy into its component wavelengths, or spectrum. The spectrum is a chemical fingerprint of the types and amounts of different elements in the gas.

Mars Odyssey Mission Status Report

NASA's Mars Odyssey orbiter put itself into a safe standby mode on Saturday, Nov. 28, and the team operating the spacecraft has begun implementing careful steps designed to resume Odyssey's science and relay operations within about a week.

Engineers have diagnosed the cause of the Nov. 28 event as the spacecraft's proper response to a memory error with a known source. The likely cause is an upset in the orbiter's "memory error external bus," as was the case with a similar event in June 2008.

In safe mode over the weekend, Odyssey remained in communication with ground controllers and maintained healthy temperatures and power. To clear the memory error, the team commanded Odyssey today to perform a cold reboot of the orbiter's onboard computer. The spacecraft reported that the reboot had been completed successfully.

"This event is a type we have seen before, so we have a known and tested path to resuming normal operations," said Odyssey Project Manager Philip Varghese of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Odyssey has been orbiting Mars since 2001. In addition to its own major scientific discoveries and continuing studies of the planet, the Odyssey mission has played important roles in supporting the missions of the Mars rovers Spirit and Opportunity and the Phoenix Mars Lander.

NASA Assessing New Roles for Ailing QuikScat Satellite

NASA mission managers are assessing options for future operations of the venerable QuikScat satellite following the age-related failure of a mechanism that spins the scatterometer antenna. This spinning antenna had been providing near-real-time ocean- surface wind speed and direction data over 90 percent of the global ocean every day.

In recent months, the QuikScat project team has been monitoring a pattern of increasing friction in the bearings that allow the antenna to spin, leading to increased resistance and strain on the motor that turns QuikScat's rotating antenna. This degradation was fully expected, as the spin mechanism was designed to last about 5 years.

After experiencing further difficulties over the weekend, the antenna stopped spinning early today, Nov. 23. The QuikScat spacecraft and scatterometer instrument themselves remain in otherwise good health. Should engineers be unable to restart the antenna, QuikScat will be unable to continue its primary science mission, as the antenna spin is necessary to estimate wind speed and direction and form the wide data swath necessary to obtain nearly global sampling.

Over the coming days, NASA managers will review contingency plans for restarting the antenna and assess options for using the mission in its present degraded state to advance Earth system science in the event the antenna cannot be restarted. For example, degraded scatterometer measurements from QuikScat can still be useful for cross-calibrating the mission's climate data record with measurements from other scatterometers, including the operational EUMETSAT ASCAT instrument, India's recently launched Oceansat-2 and a planned Chinese scatterometer. Specific operational forecasting applications such as polar ice measurements and limited hurricane observations may also be supportable.

By any measure of success, the 10-year-old QuikScat mission is a unique national resource that has achieved and far surpassed its science objectives. Designed for a two-year lifetime, QuikScat has been used around the globe by the world's operational meteorological agencies to improve weather forecasts and identify the location, size and strength of hurricanes and other storms in the open ocean. The mission has also provided critical information for monitoring, modeling, forecasting and researching our atmosphere, ocean and climate.

Cassini Captures Ghostly Dance of Saturn's Northern Lights

In the first video showing the auroras above the northern latitudes of Saturn, Cassini has spotted the tallest known "northern lights" in the solar system, flickering in shape and brightness high above the ringed planet.

The new video reveals changes in Saturn's aurora every few minutes, in high resolution, with three dimensions. The images show a previously unseen vertical profile to the auroras, which ripple in the video like tall curtains. These curtains reach more than 1,200 kilometers (750 miles) above the edge of the planet's northern hemisphere.

The new video and still images are online at: http://www.nasa.gov/cassini , http://saturn.jpl.nasa.gov and http://ciclops.org .

Auroras occur on Earth, Jupiter, Saturn and a few other planets, and the new images will help scientists better understand how they are generated.

"The auroras have put on a dazzling show, shape-shifting rapidly and exposing curtains that we suspected were there, but hadn't seen on Saturn before," said Andrew Ingersoll of the California Institute of Technology in Pasadena, who is a member of the Cassini imaging team that processed the new video. "Seeing these things on another planet helps us understand them a little better when we see them on Earth."
Cassini Captures Ghostly Dance of Saturn's Northern Lights A Cassini scientist explains the flickering "northern lights" high above Saturn, shown for the first time in a visible-light movie.Image credit: NASA/JPL/
Play now

Auroras appear mostly in the high latitudes near a planet's magnetic poles. When charged particles from the magnetosphere -- the magnetic bubble surrounding a planet -- plunge into the planet's upper atmosphere, they cause the atmosphere to glow. The curtain shapes show the paths that these charged particles take as they flow along the lines of the magnetic field between the magnetosphere and the uppermost part of the atmosphere.

Mystery of the Solar Tsunami—Solved

Sometimes you really can believe your eyes. That's what NASA's Solar Terrestrial Relations Observatory (STEREO) is telling researchers about a controversial phenomenon on the sun known as the "solar tsunami."

Years ago, when solar physicists first witnessed a towering wave of hot plasma racing across the sun's surface, they doubted their senses. The scale of the wave was staggering: It rose up higher than Earth itself and rippled out from a central point in a circular pattern millions of kilometers in circumference. Skeptical observers suggested it might be a shadow of some kind—a trick of the satellite's eye—but surely not a real wave.

"Now we know," says Joe Gurman of the Solar Physics Laboratory at NASA's Goddard Space Flight Center. "Solar tsunamis are real."

The twin STEREO spacecraft confirmed their reality in February 2009 when sunspot 11012 unexpectedly erupted. The blast hurled a billion-ton cloud of gas (a coronal mass ejection, or CME) into space and sent a tsunami racing along the sun's surface. STEREO recorded the wave from two positions separated by 90 degrees, giving researchers an unprecedented view of the event.

"It was definitely a wave," says Spiros Patsourakos of George Mason University, lead author of a paper reporting the finding in Astrophysical Journal Letters. "Not a wave of water, but a giant wave of hot plasma and magnetism."

The View from the Center of Our Solar System

* NASA's Cassini spacecraft is helping to rewrite our understanding of the shape of our solar system as it moves through the local Milky Way galaxy.
* Previous models pictured our solar system as having a comet-like appearance. The new results suggest a picture more like a bubble.
* Cassini scientists created an image from this exotic region of space by detecting particles known as energetic neutral atoms.
* It complements data collected by NASA's Interstellar Boundary Explorer.

When NASA's Cassini spacecraft began orbiting Saturn five years ago, a dozen highly-tuned science instruments set to work surveying, sniffing, analyzing and scrutinizing the Saturnian system.

But Cassini recently revealed new data that appeared to overturn the decades-old belief that our solar system resembled a comet in shape as it moves through the interstellar medium (the matter between stars in our corner of the Milky Way galaxy).

Instead, the new results suggest our heliosphere more closely resembles a bubble - or a rat - being eaten by a boa constrictor: as the solar system passes through the "belly" of the snake, the ribs, which mimic the local interstellar magnetic field, expand and contract as the rat passes. An animation is available here http://photojournal.jpl.nasa.gov/catalog/PIA12310.

"At first I was incredulous," said Tom Krimigis, principal investigator of the Magnetospheric Imaging Instrument (MIMI) at Johns Hopkins University's Applied Physics Laboratory in Laurel, Md. "The first thing I thought was, 'What's wrong with our data?'"

Krimigis and his colleagues on the instrument team published the Cassini findings in the Nov. 13 issue of the journal Science, which featured complementary results from NASA's Interstellar Boundary Explorer (IBEX). Together, the results create the first map of the heliosphere and its thick outer layer known as the heliosheath, where solar wind streaming out from the sun gets heated and slowed as it interacts with the interstellar medium.

NASA's Wise Gets Ready to Survey the Whole Sky

NASA's Wide-field Infrared Survey Explorer, or Wise, is chilled out, sporting a sunshade and getting ready to roll. NASA's newest spacecraft is scheduled to roll to the pad on Friday, Nov. 20, its last stop before launching into space to survey the entire sky in infrared light.

Wise is scheduled to launch no earlier than 6:09 a.m. PST (9:09 a.m. EST) on Dec. 9 from Vandenberg Air Force Base in California. It will circle Earth over the poles, scanning the entire sky one-and-a-half times in nine months. The mission will uncover hidden cosmic objects, including the coolest stars, dark asteroids and the most luminous galaxies.

"The eyes of Wise are a vast improvement over those of past infrared surveys," said Edward "Ned" Wright, the principal investigator for the mission at UCLA. "We will find millions of objects that have never been seen before."

The mission will map the entire sky at four infrared wavelengths with sensitivity hundreds to hundreds of thousands of times greater than its predecessors, cataloging hundreds of millions of objects. The data will serve as navigation charts for other missions, pointing them to the most interesting targets. NASA's Hubble and Spitzer Space Telescopes, the European Space Agency's Herschel Space Observatory, and NASA's upcoming Sofia and James Webb Space Telescope will follow up on Wise finds.

"This is an exciting time for space telescopes," said Jon Morse, NASA's Astrophysics Division director at NASA Headquarters in Washington. "Many of the telescopes will work together, each contributing different pieces to some of the most intriguing puzzles in our universe."

Visible light is just one slice of the universe's electromagnetic rainbow. Infrared light, which humans can't see, has longer wavelengths and is good for seeing objects that are cold, dusty or far away. In our solar system, Wise is expected to find hundreds of thousands of cool asteroids, including hundreds that pass relatively close to Earth's path. Wise's infrared measurements will provide better estimates of asteroid sizes and compositions -- important information for understanding more about potentially hazardous impacts on Earth.

"With infrared, we can find the dark asteroids other surveys have missed and learn about the whole population. Are they mostly big, small, fluffy or hard?" said Peter Eisenhardt, the Wise project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

New Moon Sets Stage for Brilliant Leonids Meteor Shower

This year's Leonids meteor shower peaks on Tuesday, Nov. 17. If forecasters are correct, the shower should produce a mild but pretty sprinkling of meteors over North America followed by a more intense outburst over Asia. The phase of the moon will be new -- setting the stage for what could be one of the best Leonid showers in years.

"We're predicting 20 to 30 meteors per hour over the Americas, and as many as 200 to 300 per hour over Asia," says Bill Cooke of the Meteoroid Environment Office at NASA's Marshall Space Flight Center. "Our forecast is in good accord with independent theoretical work by other astronomers."

Leonids are bits of debris from Comet Tempel-Tuttle. Every 33 years the comet visits the inner solar system and leaves a stream of dusty debris in its wake. Many of these streams have drifted across the November portion of Earth's orbit. Whenever our planet hits one, meteors appear to be flying out of the constellation Leo.

"We can predict when Earth will cross a debris stream with pretty good accuracy," says Cooke. "The intensity of the display is less certain, though, because we don't know how much debris is in each stream." Caveat observer!

Cyclone Phyan Raining on Tibet After Breaking a Record in India

Cyclone Phyan broke a 43 year record when it made landfall north of the city of Mumbai, India during the evening hours on November 11. NASA's Aqua satellite captured Phyan's landfall with one instrument, and a day later, another of Aqua's instruments show the storm's remnants raining Tibet as Phyan continues to dissipate.

Phyan is the first tropical cyclone to make an appearance in November in the Konkan region of India since 1996. The India Meteorological Department confirmed that the last November appearance of a storm in that region was 43 years ago. As Phyan was making landfall, NASA's Aqua satellite passed overhead, and the Moderate Imaging Spectroradiometer captured a stunning visual image of the storm on November 11 at 0845 UTC (3:45 ET).

November 12 at 1:30 p.m. local time (2:30 a.m. ET) another instrument on Aqua called the Atmospheric Infrared Sounder (AIRS) captured an image of Phyan's remnant cold clouds and showers over Tibet. The AIRS image showed that Phyan still had cold cloud tops as cold as -27F and was dumping moderate rainfall over Lake Manasarovar and Raksas Tal in Tibet.

The official final warning on Phyan was issued on November 11 at 1500 UTC (10 a.m. ET) from the U.S. Navy's Joint Typhoon Warning Center. Phyan's center was located near 19.2 degrees North latitude and 73.6 East longitude, about 30 miles east-northeast of Mumbai, India. Cyclone Phyan had maximum sustained winds near 40 knots (46 mph) and it was moving northeast near 16 mph.

According to Sifynews.com, before Phyan came ashore, the storm caused the deaths of seven fishermen. As of this morning, November 12, there are still 100 fisherman missing in the Arabian Sea because of the rough conditions the cyclone created on its approach to its landfall. Pyhan also affected the Sugar cane industry. Sugar cane harvesting was delayed because of flooded fields in Maharashtra, India’s second-biggest producer. Maharashtra is a state located on India's western coast. Other reports cited damages to more than 7,500 homes. Almost 100 were destroyed from Phyan's tropical storm force winds as wind gusts to 55 mph were reported upon Phyan's landfall.

2012 – A Scientific Reality Check

There apparently is a great deal of interest in celestial bodies, and their locations and trajectories at the end of the calendar year 2012. Now, I for one love a good book or movie as much as the next guy. But the stuff flying around through cyberspace, TV and the movies is not based on science. There is even a fake NASA news release out there… So here is the scientific reality on the celestial happenings in the year 2012.

Nibiru, a purported large object headed toward Earth, simply put - does not exist. There is no credible evidence - telescopic or otherwise - for this object's existence. There is also no evidence of any kind for its gravitational affects upon bodies in our solar system.

I do however like the name Nibiru. If I ever get a pet goldflish (and I just may do that sometime in early 2013), Nibiru will be at the top of my list.

The Mayan calendar does not end in December 2012. Just as the calendar you have on your kitchen wall does not cease to exist after December 31, the Mayan calendar does not cease to exist on December 21, 2012. This date is the end of the Mayan long-count period, but then – just as your calendar begins again on January 1 - another long-count period begins for the Mayan calendar.

There are no credible predictions for worrisome astronomical events in 2012. The activity of the sun is cyclical with a period of roughly 11 years and the time of the next solar maximum is predicted to occur in the period 2010 – 2012. However, the Earth routinely experiences these periods of increased solar activity – for eons - without worrisome effects. The Earth’s magnetic field, which deflects charged particles from the sun, does reverse polarity on time scales of about 400,000 years but there is no evidence that a reversal, which takes thousands of years to occur, will begin in 2012. Even if this several thousand year-long magnetic field reversal were to begin, that would not affect the Earth’s rotation nor would it affect the direction of the Earth’s rotation axis… only Superman can do that.

The only important gravitational tugs experienced by the Earth are due to the moon and sun. There are no planetary alignments in the next few decades, Earth will not cross the galactic plane in 2012, and even if these alignments were to occur, their effects on the Earth would be negligible. Each December the Earth and Sun align with the approximate center of the Milky Way Galaxy but that is an annual event of no consequence.

The predictions of doomsday or dramatic changes on December 21, 2012 are all false. Incorrect doomsday predictions have taken place several times in each of the past several centuries. Readers should bear in mind what Carl Sagan noted several years ago; "extraordinary claims require extraordinary evidence."

For any claims of disaster or dramatic changes in 2012, the burden of proof is on the people making these claims. Where is the science? Where is the evidence? There is none, and all the passionate, persistent and profitable assertions, whether they are made in books, movies, documentaries or over the Internet, cannot change that simple fact. There is no credible evidence for any of the assertions made in support of unusual events taking place in December 2012.

2012: Beginning of the End or Why the World Won't End?

Remember the Y2K scare? It came and went without much of a whimper because of adequate planning and analysis of the situation. Impressive movie special effects aside, Dec. 21, 2012, won't be the end of the world as we know. It will, however, be another winter solstice.

Much like Y2K, 2012 has been analyzed and the science of the end of the Earth thoroughly studied. Contrary to some of the common beliefs out there, the science behind the end of the world quickly unravels when pinned down to the 2012 timeline. Below, NASA Scientists answer several questions that we're frequently asked regarding 2012.

Question (Q): Are there any threats to the Earth in 2012? Many Internet websites say the world will end in December 2012.
Answer (A): Nothing bad will happen to the Earth in 2012. Our planet has been getting along just fine for more than 4 billion years, and credible scientists worldwide know of no threat associated with 2012.

Q: What is the origin of the prediction that the world will end in 2012?
A: The story started with claims that Nibiru, a supposed planet discovered by the Sumerians, is headed toward Earth. This catastrophe was initially predicted for May 2003, but when nothing happened the doomsday date was moved forward to December 2012. Then these two fables were linked to the end of one of the cycles in the ancient Mayan calendar at the winter solstice in 2012 -- hence the predicted doomsday date of December 21, 2012.

Q: Does the Mayan calendar end in December 2012?
A: Just as the calendar you have on your kitchen wall does not cease to exist after December 31, the Mayan calendar does not cease to exist on December 21, 2012. This date is the end of the Mayan long-count period but then -- just as your calendar begins again on January 1 -- another long-count period begins for the Mayan calendar.

Q: Could a phenomena occur where planets align in a way that impacts Earth?
A: There are no planetary alignments in the next few decades, Earth will not cross the galactic plane in 2012, and even if these alignments were to occur, their effects on the Earth would be negligible. Each December the Earth and sun align with the approximate center of the Milky Way Galaxy but that is an annual event of no consequence.

Exoplanet House of Horrors

Astronomers may be closer than ever to discovering a planet that’s habitable like our own, but along the way they’ve discovered some very scary exoplanets – places where conditions are far too harsh for life as we know it to exist.

We’ve rounded up some of the most frightening, deadly exoplanets, places that make even the scariest haunted house on Earth pale in comparison.

Radiation Bath, Anyone?

The exoplanets PSR B1257+12 b, c and d were among the first discovered, and also happen to be three of the weirdest. The entire system is a graveyard, remnants of what used to be a normal, functional solar system before the star blew apart in a giant explosion known as a supernova.

The massive shockwave from the supernova stripped away any atmosphere or living creatures that might have once lived on these planets, leaving behind ghostly, rocky shells, dead planets orbiting the corpse of an extinct star.

Except that PSR B1257+12 isn’t all dead - the remaining core from the old star has become a zombie star called a pulsar. Literally spinning in its grave, PSR B1257+12 makes a full rotation every 6.22 milliseconds and emits an intense beam of radiation that can be detected from Earth. The star’s unfortunate planets are thus bathed in deadly radiation on a regular basis, making sure that this system remains a cosmic no-man’s land.

A Mighty Wind

The sound of howling wind is a must for any Earth-based haunted house, but weather conditions on HD 189733 b make it a very dangerous place to go trick-or-treating.

At first glance, HD 189733 b looks like the typical “hot Jupiter” – a huge gas planet perched dangerously close to a burning-hot star, with daytime temperatures around a balmy 1,770 degrees Fahrenheit. HD 189733 b is “tidally locked” in its orbit, meaning that the same side of the planet always faces its star.

But when scientists measured the planet’s nighttime temperature, they were shocked to find that it was only 500 degrees cooler. How does the back side of the planet stay so warm?

The answer is wind: insanely fast, dangerous wind that whisks heat from day-side to night-side at a speed of 4,500 mph, nearly six times the speed of sound. In fact, astronomers estimate that wind speeds might top out at 22,000 mph, conditions that make hurricanes on Earth look like a breezy day at the beach.

Needless to say, kite-flying on HD 189733 b is not recommended – unless you’re flying one from the cockpit of a fighter jet.

Boil, Boil, Toil and Trouble


The planet HD 209458 b has a few things in common with Earth: water vapor, methane, and carbon dioxide in its atmosphere, key ingredients for life on our planet. Don’t be fooled, though, because this planet is a roiling cauldron of almost unimaginable heat.

Even the hottest summer days on Earth don’t get as dangerous as the conditions on HD 209458 b, a planet that orbits so close to its host star that its atmosphere is literally boiling off, ripped away from the planet as it whips around on its breakneck 3.5-day orbit. The gas that escapes from HD 209458 b forms a tail about 124,000 miles (200,000 km) long.

Scientists have found many planets like HD 209458 b – huge gas giants that orbit hazardously close to their stars and have hellishly hot, poisonous atmospheres. Sometimes, planets like these can be in danger of being swallowed whole by their host stars, as may be the case for the doomed world WASP-18b.

As far as planets go, WASP-18b is on death’s doorstep. There’s a good chance that it will be torn apart completely within the next million years, when it finally spirals too close to its star. Scientists will know within 10 years whether or not WASP-18b is on a funeral march towards its untimely demise.

All Alone and Very, Very Cold

While most of the exoplanets found so far are hellishly hot, OGLE-2005-BLG-390L b has the distinction of being the coldest exoplanet yet discovered.

The planet takes about 10 Earth years to orbit its tiny dwarf star, and it’s a chilly trip; the average temperature on OGLE-2005-BLG-390L b is 50 Kelvin, or minus 370 degrees Fahrenheit. A good costume for trick-or-treating on this frigid planet would be a toasty self-heating spacesuit, an oxygen supply, ice skates and plenty of hot cocoa.

Of course, don’t expect to find many houses with candy here, because despite the fact that it’s just a few times bigger than Earth, OGLE-2005-BLG-390L b is an uninhabitable ice ball stuck in a perpetual winter freeze. Even the coldest Halloween night in Antarctica is a balmy paradise compared to this frosty world.

NASA's Mars Odyssey Alters Orbit to Study Warmer Ground

NASA's long-lived Mars Odyssey spacecraft has completed an eight-month adjustment of its orbit, positioning itself to look down at the day side of the planet in mid-afternoon instead of late afternoon.

This change gains sensitivity for infrared mapping of Martian minerals by the orbiter's Thermal Emission Imaging System camera. Orbit design for Odyssey's first seven years of observing Mars used a compromise between what worked best for the infrared mapping and for another onboard instrument.

"The orbiter is now overhead at about 3:45 in the afternoon instead of 5 p.m., so the ground is warmer and there is more thermal energy for the camera's infrared sensors to detect," said Jeffrey Plaut of NASA's Jet Propulsion Laboratory, Pasadena, Calif., project scientist for Mars Odyssey.

Some important mineral discoveries by Odyssey stem from mapping done during six months early in the mission when the orbit geometry provided mid-afternoon overpasses. One key example: finding salt deposits apparently left behind when large bodies of water evaporated.

"The new orbit means we can now get the type of high-quality data for the rest of Mars that we got for 10 or 20 percent of the planet during those early six months," said Philip Christensen of Arizona State University, Tempe, principal investigator for the Thermal Emission Imaging System.

The Sun's Sneaky Variability

Every 11 years, the sun undergoes a furious upheaval. Dark sunspots burst forth from beneath the sun's surface. Explosions as powerful as a billion atomic bombs spark intense flares of high-energy radiation. Clouds of gas big enough to swallow planets break away from the sun and billow into space. It's a flamboyant display of stellar power.

Almost none of the drama of Solar Maximum is visible to the human eye. Look at the sun in the noontime sky and—ho-hum—it's the same old bland ball of bright light.

"The problem is, human eyes are tuned to the wrong wavelength," explains Tom Woods, a solar physicist at the University of Colorado in Boulder. "If you want to get a good look at solar activity, you need to look in the EUV."

Fires in North Korea

Multiple fires burned in North Korea in mid-October 2009, sending a plume of smoke over the Sea of Japan. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this true-color image on October 15. Red outlines indicate hotspots associated with active fires, although not all the fires have visible hotspots. The smoke plumes blow uniformly eastward, some of the individual plumes coalescing into a single large plume over the sea.

Robot Armada Might Scale New Worlds

An armada of robots may one day fly above the mountain tops of Saturn's moon Titan, cross its vast dunes and sail in its liquid lakes.

Wolfgang Fink, visiting associate in physics at the California Institute of Technology in Pasadena says we are on the brink of a great paradigm shift in planetary exploration, and the next round of robotic explorers will be nothing like what we see today.

"The way we explore tomorrow will be unlike any cup of tea we've ever tasted," said Fink, who was recently appointed as the Edward and Maria Keonjian Distinguished Professor in Microelectronics at the University of Arizona, Tucson. "We are departing from traditional approaches of a single robotic spacecraft with no redundancy that is Earth-commanded to one that allows for having multiple, expendable low-cost robots that can command themselves or other robots at various locations at the same time."

Fink and his team members at Caltech, the U.S. Geological Survey and the University of Arizona are developing autonomous software and have built a robotic test bed that can mimic a field geologist or astronaut, capable of working independently and as part of a larger team. This software will allow a robot to think on its own, identify problems and possible hazards, determine areas of interest and prioritize targets for a close-up look.

The way things work now, engineers command a rover or spacecraft to carry out certain tasks and then wait for them to be executed. They have little or no flexibility in changing their game plan as events unfold; for example, to image a landslide or cryovolcanic eruption as it happens, or investigate a methane outgassing event.

"In the future, multiple robots will be in the driver's seat," Fink said. These robots would share information in almost real time. This type of exploration may one day be used on a mission to Titan, Mars and other planetary bodies. Current proposals for Titan would use an orbiter, an air balloon and rovers or lake landers.

In this mission scenario, an orbiter would circle Titan with a global view of the moon, with an air balloon or airship floating overhead to provide a birds-eye view of mountain ranges, lakes and canyons. On the ground, a rover or lake lander would explore the moon's nooks and crannies. The orbiter would "speak" directly to the air balloon and command it to fly over a certain region for a closer look. This aerial balloon would be in contact with several small rovers on the ground and command them to move to areas identified from overhead.

"This type of exploration is referred to as tier-scalable reconnaissance," said Fink. "It's sort of like commanding a small army of robots operating in space, in the air and on the ground simultaneously."

A rover might report that it's seeing smooth rocks in the local vicinity, while the airship or orbiter could confirm that indeed the rover is in a dry riverbed - unlike current missions, which focus only on a global view from far above but can't provide information on a local scale to tell the rover that indeed it is sitting in the middle of dry riverbed.

A current example of this type of exploration can best be seen at Mars with the communications relay between the rovers and orbiting spacecraft like the Mars Reconnaissance Orbiter. However, that information is just relayed and not shared amongst the spacecraft or used to directly control them.

"We are basically heading toward making robots that command other robots," said Fink, who is director of Caltech's Visual and Autonomous Exploration Systems Research Laboratory, where this work has taken place.

"One day an entire fleet of robots will be autonomously commanded at once. This armada of robots will be our eyes, ears, arms and legs in space, in the air, and on the ground, capable of responding to their environment without us, to explore and embrace the unknown," he added.

Papers describing this new exploration are published in the journal "Computer Methods and Programs in Biomedicine" and in the Proceedings of the SPIE.

NASA Researchers Explore Lightning's NOx-ious Impact on Pollution, Climate

Every year, scientists learn something new about the inner workings of lightning.

With satellites, they have discovered that more than 1.2 billion lightning flashes occur around the world every year. (Rwanda has the most flashes per square kilometer, while flashes are rare in polar regions.) Laboratory and field experiments have revealed that the core of some lightning bolts reaches 30,000 Kelvin (53,540 ºF), a temperature hot enough to instantly melt sand and break oxygen and nitrogen molecules into individual atoms.

And then there is this: each of those billion lightning flashes produces a puff of nitrogen oxide gas (NOx) that reacts with sunlight and other gases in the atmosphere to produce ozone. Near Earth’s surface, ozone can harm human and plant health; higher in the atmosphere, it is a potent greenhouse gas; and in the stratosphere, its blocks cancer-causing ultraviolet radiation.

In 1827, the German chemist Justin von Liebig first observed that lightning produced NOx—scientific shorthand for a gaseous mixture of nitrogen and oxygen that includes nitric oxide (NO) and nitrogen dioxide (NO2). Nearly two centuries later, the topic continues to attract the attention of scientists.

Fossil fuel combustion, microbes in the soil, lightning, and forest fires all produce NOx. Scientists think lightning's contribution to Earth's NOx budget—probably about 10 percent—is relatively small compared to fossil fuel emissions. Yet they haven't been sure whether global estimates of NOx produced by lightning are accurate.

"There's still a lot of uncertainty about how much NOx lightning produces," said Kenneth Pickering, an atmospheric scientist who studies lightning at NASA's Goddard Space Flight Center in Greenbelt, Md. "Indeed, even recent published estimates of lightning's global NOx production still vary by as much as a factor of four. We're trying to narrow that uncertainty in order to improve the accuracy of both global climate models and regional air quality models."

NASA Refines Asteroid Apophis' Path Toward Earth

Using updated information, NASA scientists have recalculated the path of a large asteroid. The refined path indicates a significantly reduced likelihood of a hazardous encounter with Earth in 2036.

The Apophis asteroid is approximately the size of two-and-a-half football fields. The new data were documented by near-Earth object scientists Steve Chesley and Paul Chodas at NASA's Jet Propulsion Laboratory in Pasadena, Calif. They will present their updated findings at a meeting of the American Astronomical Society's Division for Planetary Sciences in Puerto Rico on Oct. 8.

"Apophis has been one of those celestial bodies that has captured the public's interest since it was discovered in 2004," said Chesley. "Updated computational techniques and newly available data indicate the probability of an Earth encounter on April 13, 2036, for Apophis has dropped from one-in-45,000 to about four-in-a million."

A majority of the data that enabled the updated orbit of Apophis came from observations Dave Tholen and collaborators at the University of Hawaii's Institute for Astronomy in Manoa made. Tholen pored over hundreds of previously unreleased images of the night sky made with the University of Hawaii's 2.2-meter (88-inch) telescope, located near the summit of Mauna Kea.

Tholen made improved measurements of the asteroid's position in the images, enabling him to provide Chesley and Chodas with new data sets more precise than previous measures for Apophis. Measurements from the Steward Observatory's 2.3 meter (90-inch) Bok telescope on Kitt Peak in Arizona and the Arecibo Observatory on the island of Puerto Rico also were used in Chesley's calculations.

The information provided a more accurate glimpse of Apophis' orbit well into the latter part of this century. Among the findings is another close encounter by the asteroid with Earth in 2068 with chance of impact currently at approximately three-in-a-million. As with earlier orbital estimates where Earth impacts in 2029 and 2036 could not initially be ruled out due to the need for additional data, it is expected that the 2068 encounter will diminish in probability as more information about Apophis is acquired.

Initially, Apophis was thought to have a 2.7 percent chance of impacting Earth in 2029. Additional observations of the asteroid ruled out any possibility of an impact in 2029. However, the asteroid is expected to make a record-setting -- but harmless -- close approach to Earth on Friday, April 13, 2029, when it comes no closer than 29,450 kilometers (18,300 miles) above Earth's surface.

"The refined orbital determination further reinforces that Apophis is an asteroid we can look to as an opportunity for exciting science and not something that should be feared," said Don Yeomans, manager of the Near-Earth Object Program Office at JPL. "The public can follow along as we continue to study Apophis and other near-Earth objects by visiting us on our AsteroidWatch Web site and by following us on the @AsteroidWatch Twitter feed."

The science of predicting asteroid orbits is based on a physical model of the solar system which includes the gravitational influence of the sun, moon, other planets and the three largest asteroids.

NASA detects and tracks asteroids and comets passing close to Earth using both ground and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet.

JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena. Cornell University, Ithaca, N.Y., operates the Arecibo Observatory under a cooperative agreement with the National Science Foundation in Arlington, Va.

Google Earth Application Maps Carbon's Course

Sometimes a picture really is worth a thousand words, particularly when the picture is used to illustrate science. Technology is giving us better pictures every day, and one of them is helping a NASA-funded scientist and her team to explain the behavior of a greenhouse gas.

Google Earth -- the digital globe on which computer users can fly around the planet and zoom in on key features -- is attracting attention in scientific communities and aiding public communication about carbon dioxide. Recently Google held a contest to present scientific results using KML, a data format used by Google Earth.

"I tried to think of a complex data set that would have public relevance," said Tyler Erickson, a geospatial researcher at the Michigan Tech Research Institute in Ann Arbor.

He chose to work with data from NASA-funded researcher Anna Michalak of the University of Michigan, Ann Arbor, who develops complex computer models to trace carbon dioxide back in time to where it enters and leaves the atmosphere.

"The datasets have three spatial dimensions and a temporal dimension," Erickson said. "Because the data is constantly changing in time makes it particularly difficult to visualize and analyze."

A better understanding of the carbon cycle has implications for energy and environmental policy and carbon management. In June 2009, Michalak described this research at the NASA Earth System Science at 20 symposium in Washington, D.C.

A snapshot from Erickson's Google Earth application shows green tracks representing carbon dioxide in the lowest part of the atmosphere close to Earth's surface where vegetation and land processes can impact the carbon cycle. Red tracks indicate particles at higher altitudes that are immune from ground influences.

The application is designed to educate the public and even scientists about how carbon dioxide emissions can be traced. A network of 1,000-foot towers across the United States is equipped with instruments by NOAA to measure the carbon dioxide content of parcels of air at single locations.

The application is designed to educate the public and even scientists about how carbon dioxide emissions can be traced. A network of 1,000-foot towers across the United States, like the tower above, are equipped with instruments by NOAA to measure the carbon dioxide content of parcels of air at single locations.

But where did that gas come from and how did it change along its journey? To find out, scientists rely on a sleuthing technique called "inverse modeling" – measuring gas concentrations at a single geographic point and then using clues from weather and atmospheric models to deduce where it came from. The technique is complex and difficult to explain even to fellow scientists.

Michalak related the technique to cream in a cup of coffee. "Say someone gave you a cup of creamy coffee," Michalak said. "How do you know when that cream was added?" Just as cream is not necessarily mixed perfectly, neither is the carbon dioxide in the atmosphere. If you can see the streaks of cream (carbon dioxide) and understand how the coffee (atmosphere) was stirred (weather), then scientists can use those clues to retrace the time and location that the ingredient was added to the mix.

The visual result typically used by scientists is a static two-dimensional map of the location of the gas, as averaged over the course of a month. Most carbon scientists know how to interpret the 2D map, but visualizing the 3D changes for non-specialists has proved elusive. Erickson spent 70 hours programming the Google Earth application that makes it easy to navigate though time and watch gas particles snake their way toward the NOAA observation towers. For his work, Erickson was declared one of Google's winners in March 2009.

"Having this visual tool allows us to better explain the scientific process," Michalak said. "It's a much more human way of looking at the science."

The next step, Erickson said, is to adapt the application to fit the needs of the research community. Scientists could use the program to better visualize the output of complex atmospheric models and then improve those models so that they better represent reality.

"Encouraging more people to deliver data in an interactive format is a good trend," Erickson said. "It should help innovation in research by reducing barriers to sharing data."

Galileo's Jupiter Journey Began Two Decades Ago

• Launch: Oct. 18, 1989, from Kennedy Space Center, Fla., on space shuttle Atlantis on mission STS-34


• Arrival in orbit around Jupiter: Dec. 7, 1995


• VEEGA (Venus-Earth-Earth Gravity Assist) is the acronym mission planners gave for Galileo's flight path through the inner solar system


• Observed impacts of fragments from comet Shoemaker-Levy 9 into Jupiter


• Approximate number of people (from around the world) who worked on the Galileo mission: 800


• More than 100 scientists from United States, Great Britain, Germany, France, Canada and Sweden carried out Galileo's experiments

PASADENA, Calif. - NASA's Galileo spacecraft began what would become a 14-year odyssey of exploration 20 years ago this Sunday, Oct. 18. Galileo was humanity's first emissary to orbit a planet in the outer solar system - Jupiter.

Galileo was launched into space aboard the space shuttle Atlantis on Oct. 18, 1989, from Kennedy Space Center, Florida. The crew of Atlantis deployed Galileo out of the shuttle's cargo bay only hours after launch. Then, a little over seven hours after leaving Earth, Galileo was propelled onto its interplanetary flight path by a two-stage, solid-fuel motor called an Inertial Upper Stage. Although earlier plans called for Galileo to use a more powerful upper stage so that it could fly directly to Jupiter, the final flight took it by other planets first so that it could gain energy from the gravity of each. Galileo flew past Venus on Feb. 10, 1990, and then twice past Earth -- once on Dec. 8, 1990, and again on Dec. 8, 1992.

Even before its arrival at Jupiter in 1995, Galileo was making groundbreaking discoveries. On Oct. 29, 1991, the spacecraft flew past asteroid Gaspra - sending back the first close up images of one of these celestial wanderers. Then on Aug. 28, 1993, Galileo encountered the 15.2-kilometer-wide (9.4-mile) asteroid Ida, where it took the first images of an asteroid and discovered the first asteroid moon, the 1.6-kilometer-wide (1-mile) Dactyl. During the latter part of its interplanetary cruise, Galileo was used to observe the collisions of fragments of Comet Shoemaker-Levy with Jupiter in July 1994.

Galileo arrived at Jupiter on Dec. 7, 1995, entering orbit and dropping a probe into the giant planet's atmosphere. The probe's velocity as it entered Jupiter's atmosphere was a blistering 47.6 kilometers per second (106,500 miles per hour). After the atmospheric drag and a deployed parachute slowed its descent rate, the probe relayed to Galileo the first in-place studies of Jupiter's clouds and winds, furthering scientists' understanding of how the gas giant evolved. The probe also made composition measurements designed to assess the degree of evolution of Jupiter compared to the sun.

While the descent of the probe was a highlight of Galileo's mission, it was hardly the only one. Galileo extensively investigated the geologic diversity of Jupiter's four largest moons: Ganymede, Callisto, Io and Europa. It found that Io's extensive volcanic activity is 100 times greater than that found on Earth. Galileo discovered strong evidence that Jupiter's moon Europa has a melted saltwater ocean under an ice layer on its surface. Scientists estimate such an ocean could be up to 100 kilometers (62 miles) deep underneath its frozen surface and contain about twice as much water as all of Earth's oceans. Data showed moons Ganymede and Callisto may also have a liquid-saltwater layer. The biggest discovery surrounding Ganymede was the presence of a magnetic field. No other moon of any planet is known to have one.

When Galileo turned its instruments towards the giant gas world itself, the spacecraft made the first observations of ammonia clouds in another planet's atmosphere. It also observed numerous thunderstorms on Jupiter many times larger than those on Earth, with lightning strikes up to 1,000 times more powerful than on Earth. It was the first spacecraft to dwell in a giant planet's magnetosphere long enough to identify its global structure and to investigate the dynamics of Jupiter's magnetic field. Galileo determined that Jupiter's ring system is formed by dust kicked up as interplanetary meteoroids smash into the planet's four small inner moons. Galileo data showed that Jupiter's outermost ring is actually two rings, one embedded within the other.

Having traveled approximately 4.6 billion kilometers (about 2.8 billion miles), the hardy spacecraft endured more than four times the cumulative dose of harmful Jovian radiation it was designed to withstand -- and still major systems functioned. But while it was still enjoying relatively good health, the spacecraft's propellant was low. Without propellant, Galileo would not be able to point its antenna toward Earth or adjust its trajectory, so controlling the spacecraft would no longer be possible. Mission managers at NASA and JPL decided to place their resilient Jovian explorer on a collision course with Jupiter to eliminate any chance of an unwanted impact between the spacecraft and Europa. The possibility of life existing on Europa is so compelling and has raised so many unanswered questions that it is prompting plans for future spacecraft to return to the icy moon.

The Galileo spacecraft's 14-year odyssey came to an end on Sunday, Sept. 21, 2003, when the spacecraft passed into Jupiter's shadow, then disintegrated in the planet's dense atmosphere at 11:57 a.m. Pacific Daylight Time. Its entry speed was 48.2 kilometers per second (nearly 108,000 miles per hour). That is the equivalent of traveling from Los Angeles to New York City in 82 seconds.

JPL's Deep Space Network tracking station in Goldstone, Calif., received the last signal at 12:43:14 PDT, 46 minutes after it was sent. The delay is due to the time it takes for the signal to travel to Earth. Hundreds of former Galileo project members and their families were present at JPL for a celebration to bid the spacecraft goodbye.

Galileo project scientist Torrence Johnson said at the time, "We haven't lost a spacecraft, we've gained a steppingstone into the future of space exploration."

JPL, a division of the California Institute of Technology in Pasadena, managed the Galileo mission for NASA. JPL designed and built the Galileo orbiter, and operated the mission.