NASA Hosts 150 Twitter Followers at Mars Rover Launch

NASA has invited 150 followers of the agency's Twitter account to a two-day launch Tweetup on Nov. 23 and 25 at the agency's Kennedy Space Center in Florida.

The Tweetup is expected to culminate in the launch of the Mars Science Laboratory's Curiosity rover aboard an Atlas V rocket from nearby Cape Canaveral Air Force Station.

The launch window is scheduled to open at 7:25 a.m. PST (10:25 a.m. EST) on Nov. 25. Curiosity's arrival at Mars' Gale Crater is anticipated in August 2012. During the nearly two-year prime mission, the rover will investigate whether a selected area of Mars offered environmental conditions favorable for microbial life and preserved that evidence, if it existed.

Tweetup participants were selected from more than 1,050 people who registered online. They will share their Tweetup experiences with their followers through the social networking site Twitter and other online forums.

Participants represent the United States, Australia, Belgium, Brazil, Canada, France, Germany, Ireland, Spain and the United Kingdom. Attendees from the U.S. come from the District of Columbia and 37 states: Alabama, Arizona, California, Connecticut, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Virginia, Washington and Wisconsin.

Beginning at 8 a.m. PST (11 a.m. EST) on Wednesday, Nov. 23, NASA will broadcast a portion of the Tweetup when attendees talk with Jim Green, Planetary Science division director, and Doug McCuistion, Mars Exploration program director, both from NASA Headquarters in Washington. Engineers from NASA's Jet Propulsion Laboratory, Pasadena, Calif., where the rover was designed and built, will speak, as will mission scientists.

For more info, read http://www.nasa.gov/mission_pages/msl/news/msl20111116.html

Hovering on the Horizon

The limb of the Earth is a work of awesome beauty and a gift to science. When observed from space, the palette of gaseous layers of atmosphere reminds us of the fragility and tenuousness of the cocoon that shelters life from cold, harsh space. That same view also allows scientists to detect the gases and particles that make up our different layers of our atmosphere. Astronauts aboard the International Space Station captured a bit of both in this digital photograph from July 31, 2011. They threw in the Moon as an extra gift.

Closest to Earth's surface, the orange-red glow reveals Earth's troposphere—the lowest, densest layer of the atmosphere, and the one we live within. A brown transitional layer is the upper edge of the troposphere, known as the tropopause. A milky white and gray layer sits above that, likely a slice of the stratosphere with perhaps some noctilucent clouds thrown in. The upper reaches of the atmosphere - the mesosphere, thermosphere, and exosphere - fade from shades of blue to the blackness of space.

The different colors occur because the dominant gases and particles in each layer act like prisms filtering out certain colors of light. Instruments carried on satellites and on craft such as the space shuttle have allowed scientists to decipher characteristics of the ozone layer and the climate-altering effects of aerosols.

A thin crescent of the Moon is illuminated by the Sun below the horizon of the Earth. Though the Moon is more than 384,400 kilometers (238,855 miles) away, the perspective from the camera makes it appear to be a part of our atmosphere.

Landsat in Memory of the World Register

The Landsat Multispectral Scanner (MSS) data archive of 652,000 images of Earth was nominated to be part of the register in 2010. In 2011, it was officially accepted along with six other submissionsincluding Byzantine manuscripts from Georgia and early reports from the 1922 first flight across the South Atlantic.

As stated in the Landsat nomination: “There is simply no other image record of the Earth’s land regions at this scale or over the same period of time (1972-1992).”

The image above, showing southern California, is one of thousands in the twenty-year archive. Landsat MSS acquired the image on May 18, 1978. Plant-covered land is red, with forests on the mountain ranges a darker shade than vegetation at lower elevations. Bare ground and cities are pale blue, and water is dark blue and black. The image provides a baseline from which scientists can measure changes in land use, urban growth, or the impacts of natural disasters.

All U.S.-held Landsat data are managed by the U.S. Geological Survey, which maintains original digital files in its primary archives, plus back-up copies in off-site locations. Each Landsat “scene” - with 79-meter spatial resolution and 185-by-185 kilometer area - fills an important scientific niche because the sensor provided global, seasonal coverage. Its images are also detailed enough to characterize human activities, such as urban expansion, agricultural irrigation, and deforestation.

New NASA Missions to Investigate How Mars Turned Hostile

Maybe because it appears as a speck of blood in the sky, the planet Mars was named after the Roman god of war. From the point of view of life as we know it, that's appropriate. The Martian surface is incredibly hostile for life. The Red Planet's thin atmosphere does little to shield the ground against radiation from the Sun and space. Harsh chemicals, like hydrogen peroxide, permeate the soil. Liquid water, a necessity for life, can't exist for very long here—any that does not quickly evaporate in the diffuse air will soon freeze out in subzero temperatures common over much of the planet.

It wasn't always this way. There are signs that in the distant past, billions of years ago, Mars was a much more inviting place. Martian terrain is carved with channels that resemble dry riverbeds. Spacecraft sent to orbit Mars have identified patches of minerals that form only in the presence of liquid water.

The Mars Science Laboratory (MSL) mission features Curiosity, the largest and most advanced rover ever sent to the Red Planet. The Curiosity rover bristles with multiple cameras and instruments, including Goddard's Sample Analysis at Mars (SAM) instrument suite. By looking for evidence of water, carbon, and other important building blocks of life in the Martian soil and atmosphere, SAM will help discover whether Mars ever had the potential to support life. Scheduled to launch in late November or December 2011, Curiosity will be delivered to Gale crater, a 96-mile-wide crater that contains a record of environmental changes in its sedimentary rock, in August 2012.

Potential New NASA Mission Would Reveal the Hearts of Undead Stars

Neutron stars have been called the zombies of the cosmos, shining on even though they're technically dead, and occasionally feeding on a neighboring star if it gets too close.

They are born when a massive star runs out of fuel and collapses under its own gravity, crushing the matter in its core and blasting away its outer layers in a supernova explosion that can outshine a billion suns.

The core, compressed by gravity to inconceivable density – one teaspoon would weigh about a billion tons on Earth – lives on as a neutron star. Although the nuclear fusion fires that sustained its parent star are extinguished, it still shines with heat left over from its explosive formation, and from radiation generated by its magnetic field, which became intensely concentrated as the core collapsed, and can be over a trillion times stronger than Earth's.

Although its parent star could easily have been more than a million miles across, a neutron star is only about the size of a city. However, its intense gravity makes it the ultimate trash compactor, capable of packing in an astonishing amount of matter, more than 1.4 times the content of the Sun, or at least 460,000 Earths.

"A neutron star is right at the threshold of matter as it can exist – if it gets any denser, it becomes a black hole," says Dr. Zaven Arzoumanian of NASA's Goddard Space Flight Center in Greenbelt, Md.

Arzoumanian is Deputy Principal Investigator on a proposed mission called the Neutron Star Interior Composition Explorer (NICER) that would unveil the dark heart of a neutron star. "We have no way of creating neutron star interiors on Earth, so what happens to matter under such incredible pressure is a mystery – there are many theories about how it behaves. The closest we come to simulating these conditions is in particle accelerators that smash atoms together at almost the speed of light. However, these collisions are not an exact substitute – they only last a split second, and they generate temperatures that are much higher than what's inside neutron stars."

For more info, visit: http://www.nasa.gov/topics/universe/features/nicer-science.html

NASA's Chandra Contributes to Black Hole Birth Announcement

New details about the birth of a famous black hole that took place millions of years ago have been uncovered, thanks to a team of scientists who used data from NASA's Chandra X-ray Observatory as well as from radio, optical and other X-ray telescopes.

Over three decades ago, Stephen Hawking placed - and eventually lost - a bet against the existence of a black hole in Cygnus X-1. Today, astronomers are confident the Cygnus X-1 system contains a black hole, and with these latest studies they have remarkably precise values of its mass, spin, and distance from Earth. With these key pieces of information, the history of the black hole has been reconstructed.

"This new information gives us strong clues about how the black hole was born, what it weighed and how fast it was spinning," said author Mark Reid of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass. "This is exciting because not much is known about the birth of black holes."

Reid led one of three papers - all appearing in the November 10th issue of The Astrophysical Journal - describing these new results on Cygnus X-1. The other papers were led by Jerome Orosz from San Diego State University and Lijun Gou, also from CfA.

Cygnus X-1 is a so-called stellar-mass black hole, a class of black holes that comes from the collapse of a massive star. The black hole is in close orbit with a massive, blue companion star.

Using X-ray data from Chandra, the Rossi X-ray Timing Explorer, and the Advanced Satellite for Cosmology and Astrophysics, a team of scientists was able to determine the spin of Cygnus X-1 with unprecedented accuracy, showing that the black hole is spinning at very close to its maximum rate. Its event horizon - the point of no return for material falling towards a black hole - is spinning around more than 800 times a second.

An independent study that compared the evolutionary history of the companion star with theoretical models indicates that the black hole was born some 6 million years ago. In this relatively short time (in astronomical terms), the black hole could not have pulled in enough gas to ramp up its spin very much. The implication is that Cygnus X-1 was likely born spinning very quickly.

For more info, read http://www.nasa.gov/mission_pages/chandra/news/cygnusx1.html