NASA's Chandra Reveals Origin of Key Cosmic Explosions

New findings from NASA's Chandra X-ray Observatory have provided a major advance in understanding a type of supernova critical for studying the dark energy that astronomers think pervades the universe. The results show mergers of two dense stellar remnants are the likely cause of many of the supernovae that have been used to measure the accelerated expansion of the universe.

These supernovae, called Type 1a, serve as cosmic mile markers to measure expansion of the universe because they can be seen at large distances, and they follow a reliable pattern of brightness. However, until now, scientists have been unsure what actually causes the explosions.

"These are such critical objects in understanding the universe," said Marat Gilfanov of the Max PlanckInstitute for Astrophysics in Germany and lead author of the study that appears in the Feb. 18 edition of the journal Nature. "It was a major embarrassment that we did not know how they worked. Now we are beginning to understand what lights the fuse of these explosions."

Perspective View of Layered Mound in Gale Crater, Mars

This oblique view shows geological layers of rock exposed on a mound inside Gale Crater on Mars. This is a lower portion of the mound, with the crater floor at the left (and lowest) edge of the image. Layers near the bottom of the mound contain clay and sulfate minerals that indicate wet conditions. Overlying rock layers contain sulfates with little or no clay, consistent with these layers forming in an environment in which water was evaporating and Mars was drying out.

This view was created from a three-dimensional topographic model of the mound. The U.S. Geological Survey generated the model from a stereo pair of images taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Observations of the site by the Compact Reconnaissance Imaging Spectrometer for Mars, on the same orbiter, yielded information about composition. The vertical dimension is exaggerated three-fold relative to the horizontal dimensions. The view is toward the southeast. The width of the area included in the image is about 1.5 kilometers (about 5,000 feet). The scale bar in the labeled version is 200 meters (656 feet).

Radar Studies Continue in Hispaniola

NASA radar imaging flights over Central America, Haiti and the Dominican Republic are in the second week of a three-week campaign.

The JPL-developed Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) is currently in the second week of a three-week campaign in Central America, Haiti and the Dominican Republic. Flying beneath the belly of a modified Gulfstream III aircraft from NASA’s Dryden Flight Research Center, the sophisticated radar can spot minute changes in Earth's surface by flying precise repeat passes over targeted areas.

The Central American survey flights are focusing on measuring biomass in Central American rain forests, imaging volcanoes from Guatemala to Costa Rica, and imaging Mayan ruins. The flights over Haiti and the Dominican Republic are targeting earthquake faults on the island of Hispaniola. Scientists collected data over Central American nations again on Feb. 2, and then flew a second set of data tracks over Haiti on Feb. 3 before returning to Costa Rica on Feb. 4.

Envisioning Future Flight

Today's students will be designing tomorrow's aircraft, and NASA's Fundamental Aeronautics Student Competition gives them a head start.

Each year, the competition challenges students to research a particular real-world issue in aeronautics and to develop their own solutions to the problem.

Past participants in NASA's Fundamental Aeronautics Student Competition said the experience was a rewarding one that helped them learn more about aeronautics and encouraged them to improve their approaches to research and creative problem-solving.

In the 2008-2009 competition, students were challenged to develop ideas for making commercial supersonic air transportation available by 2020. Contest participants did so by examining obstacles to supersonic transportation and proposing solutions. In an additional challenge, some students submitted designs for a small supersonic airliner.

Cassini's Next Look at Titan

Sixteen days after last visiting Saturn's largest moon, NASA's Cassini spacecraft returns for another look-see of the cloud-shrouded moon - this time from on high. The flyby on Thursday, Jan. 28, referred to as "T-66" in the hollowed halls of Cassini operations, will place the spacecraft within 7,490 kilometers (4,654 miles) above the surface during time of closest approach.

While this latest close approach places Cassini more than 6,400 kilometers (3,970 miles) higher above Titan's surface than the Jan. 12 flyby, it should not considered of lesser scientific value. Instead, this high-altitude encounter will provide an opportunity for some of the spacecraft's instruments to gain another unique perspective on this crepuscular world.

First of Many Asteroid Finds

The red dot at the center of this image is the first near-Earth asteroid discovered by NASA's Wide-Field Infrared Survey Explorer, or WISE -- an all-sky mapping infrared mission designed to see all sorts of cosmic objects.

Near-Earth objects are asteroids and comets with orbits that come close to Earth's path around the sun. This particular asteroid, called 2010 AB78, is roughly one kilometer (0.6 miles) in diameter, and is currently about 158 million kilometers (98 million miles) away from Earth. Its elliptical-shaped orbit takes it out beyond Mars and back in about as close to the sun as Earth. Because the asteroid's orbit is tilted relative to the plane of our solar system, astronomers do not think it poses a hazard to our planet. As with all near-Earth objects, 2010 AB78 will continue to be monitored.

The image shows three infrared wavelengths, with red representing the longest wavelength of 12 microns, and green and blue showing 4.6- and 3.4-micron light, respectively. The asteroid appears redder than the rest of the background stars because it is cooler and emits most of its light at longer infrared wavelengths. In visible light, this space rock is very faint and difficult to see.

WISE, which began its all-sky survey on Jan. 14, 2010, is expected to find about one hundred thousand previously undiscovered asteroids in the Main Belt between Mars and Jupiter, and hundreds of new near-Earth asteroids. It will also spot millions of new stars and galaxies.

Rover Gives NASA an "Opportunity" to View Interior of Mars

NASA's Mars Exploration Rover Opportunity examined a rock called "Marquette Island" from mid-November 2009 until mid-January 2010. Studies of texture and composition suggest that this rock, not much bigger than a basketball, originated deep inside the Martian crust. A crater-digging impact could have excavated the rock and thrown it a long distance, to where Opportunity found it along the rover's long trek across the Meridiani plain toward Endeavour Crater.

This approximately true-color view of Marquette Island comes from combining three exposures that Opportunity's panoramic camera (Pancam) took through different filters during the rover's 2,117th Martian day, or sol, on Mars (Jan. 6, 2010). On the preceding sol, Opportunity's rock abrasion tool brushed dust out of the circular area where that tool had ground into the rock on sols 2100 and 2103 (Dec. 20 and 23, 2009). The dark circle left by the rock abrasion tool's work is approximately 5 centimeters (2 inches) in diameter.

Second Warmest Year on Record; End of Warmest Decade

2009 was tied for the second warmest year in the modern record, a new NASA analysis of global surface temperature shows. The analysis, conducted by the Goddard Institute for Space Studies (GISS) in New York City, also shows that in the Southern Hemisphere, 2009 was the warmest year since modern records began in 1880.

Although 2008 was the coolest year of the decade -- due to strong cooling of the tropical Pacific Ocean -- 2009 saw a return to near-record global temperatures. The past year was only a fraction of a degree cooler than 2005, the warmest year on record, and tied with a cluster of other years --1998, 2002, 2003, 2006 and 2007 1998 and 2007 -- as the second warmest year since recordkeeping began.

“There’s always an interest in the annual temperature numbers and on a given year’s ranking, but usually that misses the point,” said James Hansen, the director of GISS. “There's substantial year-to-year variability of global temperature caused by the tropical El Niño-La Niña cycle. But when we average temperature over five or ten years to minimize that variability, we find that global warming is continuing unabated."

Endeavour's STS-130 Mission

Commander George Zamka will lead the STS-130 mission to the International Space Station aboard space shuttle Endeavour. Terry Virts will serve as the pilot. Mission Specialists are Nicholas Patrick, Robert Behnken, Stephen Robinson and Kathryn Hire. Virts will be making his first trip to space.

Shuttle Endeavour and its crew will deliver to the space station a third connecting module, the Italian-built Tranquility node and the seven-windowed cupola, which will be used as a control room for robotics. The mission will feature three spacewalks.

Liftoff from NASA's Kennedy Space Center in Florida is targeted for February 7, 2010, at 4:39 a.m. EST

Solar Scientists Use 'Magnetic Mirror Effect' to Reproduce IBEX Observation

Ever since NASA's Interstellar Boundary Explorer, or IBEX, mission scientists released the first comprehensive sky map of our solar system's edge in particles, solar physicists have been busy revising their models to account for the discovery of a narrow "ribbon" of bright emission that was completely unexpected and not predicted by any model at the time.

Further study by a team of scientists funded through NASA's Heliophysics Guest Investigator program has produced a revised model that explains and closely reproduces the IBEX result by incorporating a single new effect into an existing model. The new effect, put forward by the IBEX team soon after sighting of the ribbon, is that the magnetic field surrounding our solar system—called the local galactic magnetic field—acts like a mirror for the particles that IBEX sees.

Sun Glints Seen from Space Signal Oceans and Lakes

In two new videos from NASA’s Deep Impact spacecraft, bright flashes of light known as sun glints act as beacons signaling large bodies of water on Earth. These observations give scientists a way to pick out planets beyond our solar system (extrasolar planets) that are likely to have expanses of liquid, and so stand a better chance of having life.

These sun glints are like sunshine glancing off the hood of a car. We can see them reflecting off a smooth surface when we are positioned in just the right way with respect to the sun and the smooth surface. On a planetary scale, only liquids and ice can form a surface smooth enough to produce the effect—land masses are too rough—and the surface must be very large. To stand out against a background of other radiation from a planet, the reflected light must be very bright. We won’t necessarily see glints from every distant planet that has liquids or ice.

“But these sun glints are important because, if we saw an extrasolar planet which had glints that popped up periodically, we would know that we were seeing lakes, oceans or other large bodies of liquid, such as water,” says Drake Deming, of NASA’s Goddard Space Flight Center in Greenbelt, Md. Deming is the deputy principal investigator who leads the team that works on the Extrasolar Planet Observations and Characterization (EPOCh) part of Deep Impact’s extended mission, called EPOXI. “And if we found large bodies of water on a distant planet, we would become much more optimistic about finding life.”

One of EPOCh’s goals is to observe the Earth from far away—in this case, about 11 million miles away—so that we know what an Earth-like planet would look like when viewed from our spacecraft. The images in these videos were collected when the spacecraft was close enough to resolve some of Earth’s features, but at the same time, Earth could be treated as a very distant, single point. “This allows us to properly simulate what we would have observed if Earth were an extrasolar planet,” says Michael A’Hearn, principal investigator for EPOXI.

Massive Black Hole Implicated in Stellar Destruction

New results from NASA's Chandra X-ray Observatory and the Magellan telescopes suggest that a dense stellar remnant has been ripped apart by a black hole a thousand times as massive as the Sun. If confirmed, this discovery would be a cosmic double play: it would be strong evidence for an intermediate mass black hole, which has been a hotly debated topic, and would mark the first time such a black hole has been caught tearing a star apart.

This scenario is based on Chandra observations, which revealed an unusually luminous source of X-rays in a dense cluster of old stars, and optical observations that showed a peculiar mix of elements associated with the X-ray emission. Taken together, a case can be made that the X-ray emission is produced by debris from a disrupted white dwarf star that is heated as it falls towards a massive black hole. The optical emission comes from debris further out that is illuminated by these X-rays.

The intensity of the X-ray emission places the source in the "ultraluminous X-ray source" or ULX category, meaning that it is more luminous than any known stellar X-ray source, but less luminous than the bright X-ray sources (active galactic nuclei) associated with supermassive black holes in the nuclei of galaxies. The nature of ULXs is a mystery, but one suggestion is that some ULXs are black holes with masses between about a hundred and several thousand times that of the Sun, a range intermediate between stellar-mass black holes and supermassive black holes located in the nuclei of galaxies.

GOES-K, later renamed GOES-10

NOAA anticipated the end of GOES-10 several months ahead of time, and began deactivating GOES-10 on December 1 when it fired the spacecraft’s thrusters moving the satellite into a higher orbit above the Earth. On December 2, NOAA finished its third and final, firing putting it safely out of commission and put it in an unused drift orbit.

GOES-10 was originally planned for a five-year mission when it was launched in April 1997. It was positioned as NOAA’s GOES-West satellite, more than 22,000 miles above the Earth’s surface. In 2006 a newer satellite, GOES-11, replaced GOES-10. NOAA then repositioned GOES-10 to support hurricane forecasting efforts in South America. NOAA anticipates moving GOES-12 to provide coverage for South America by May 2010.

"GOES-10 has served America – and other nations – admirably and well beyond its expected lifespan," said Mary Kicza, assistant administrator for NOAA’s Satellite and Information Service. "The success of GOES-10, built by Space Systems/Loral, was a credit to a large team of NOAA staff, who acquired and managed the spacecraft and processed and distributed the data to users." Kicza added that with the help of its partners, including NASA, "NOAA is creating better satellites that will provide better data that improve our understanding – and prediction – of climate and weather."

Suzaku Finds "Fossil" Fireballs from Supernovae

In the supernova remnant W49B, Suzaku found another fossil fireball. It detected X-rays produced when heavily ionized iron atoms recapture an electron. This view combines infrared images from the ground (red, green) with X-ray data from NASA's Chandra X-Ray Observatory.

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.

Right-Front and Right-Rear Wheels Sit Out Latest Drive

Spirit's drive on Sol 2120 included commands for using all six wheels. However, the right-front wheel rotated less than 2 degrees and the right-rear wheel did not rotate at all. The other four wheels completed enough rotations to drive about 10 meters (33 feet), but produced no measurable forward motion by the rover.

The rover team plans to command further driving this week while continuing to assess the possibility of getting more motion from the right-front wheel.

Mayon Volcano, The Phillipines

Tens of thousands of people living within the danger zone of Mayon Volcano in the Philippines were forced to evacuate to emergency shelters in mid-December 2009 as small earthquakes, incandescent lava at the summit and minor ash falls suggested a major eruption was on the way. On the evening of Dec. 14, the local volcano observatory raised the alert level to Level 3, which means "magma is close to the crater and hazardous explosive eruption is imminent."

This natural-color image of Mayon was captured on Dec. 15, 2009, by the Advanced Land Imager on NASA's Earth Observing-1 (EO-1) satellite. A small plume of ash and steam is blowing west from the summit. Dark-colored lava or debris flows from previous eruptions streak the flanks of the mountain. A ravine on the southeast slope is occupied by a particularly prominent lava or debris flow.

The Phillipine Star said on Dec. 22 that "ashfall blanketed at least three towns in Albay, raising new health fears for thousands already bracing for an eruption that could come at any time ... Health officials warned the tiny particles could cause respiratory problems or skin diseases, and could affect the thousands of people crammed into evacuation centers.

Also on Dec. 22, CNN reported that "tens of thousands of people have already fled their homes. More than 9,000 families -- a total of 44,394 people -- are being housed in evacuation camps after authorities raised the alert status of the country's most active volcano" as "fountains of red-hot lava shot up from the intensifying Mayon volcano."

Terra Turns Ten: Snow, Clouds and Sunlight

NASA flies three large, multi-sensor satellites that monitor Earth’s land, atmosphere, oceans and energy balance. Because the instruments on each satellite take measurements at the same time from the same vantage point, scientists are able to compare observations and tease out connections between different parts of the Earth system. The first of the three satellites, Terra, launched ten years ago on Dec. 18, 1999. In the decade since Terra launched, scientists have gained insight into the intricate connections that shape our planet's climate. The relationship between snow, clouds, and sunlight is a good example.

In November, the chill and snow of a Northern Hemisphere winter is on the horizon. Snow covers the far north and high elevations, as shown in the map of percent snow cover in November 2009. White areas show where snow covers the ground completely, while blue points to areas with partial snow cover. At the peak of the northern winter, more than 40 percent of the Earth’s land will be covered in snow.

In addition to being an important, life-sustaining source of water, the snow also reflects sunlight, limiting the amount of heat the Earth absorbs from the sun.

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.

New Cool Stars

Astronomers think there are roughly as many brown dwarfs as regular stars like our sun, but brown dwarfs are often too cool to find using visible light. These tiny orbs are similar to stars but they are cooler and less massive. They lack the mass to fuse atoms at their cores and shine with starlight. Using infrared light, NASA's Wide-field Infrared Survey Explorer (WISE), will find many dozens of brown dwarfs within 25 light years of the sun.

These two pictures show simulated data before and after the WISE mission (stars are not real). The simulated picture on the left shows known stars (white and yellow) and brown dwarfs (red) in our solar neighborhood. The picture on the right shows additional brown dwarfs WISE is expected to find. One of these newfound brown dwarfs could even be closer to us than our closest known star, Proxima Centauri, which is four light-years away.