SwRI-Led Team Calculates The Radiation Exposure Associated With A Trip To Mars

On November 26, 2011, the Mars Science Laboratory began a 253-day, 560-million-kilometer journey to deliver the Curiosity rover to the Red Planet. En route, the Southwest Research Institute-led Radiation Assessment Detector (RAD) made detailed measurements of the energetic particle radiation environment inside the spacecraft, providing important insights for future human missions to Mars.

“In terms of accumulated dose, it’s like getting a whole-body CT scan once every five or six days,” said Dr. Cary Zeitlin, a principal scientist in SwRI’s Space Science and Engineering Division and lead author of Measurements of Energetic Particle Radiation in Transit to Mars on the Mars Science Laboratory, scheduled for publication in the journal Science on May 31.

“Understanding the radiation environment inside a spacecraft carrying humans to Mars or other deep space destinations is critical for planning future crewed missions,” Zeitlin said. “Based on RAD measurements, unless propulsion systems advance rapidly, a large share of mission radiation exposure will be during outbound and return travel, when the spacecraft and its inhabitants will be exposed to the radiation environment in interplanetary space, shielded only by the spacecraft itself.”

Full Story: http://www.swri.org/9what/releases/2013/rad.htm#.UagaCH4o5hF

Low Sodium Diet Key To Old Age For Stars

Credit: ESO

Astronomers expect that stars like the Sun will blow off much of their atmospheres into space near the ends of their lives. But new observations of a huge star cluster made using ESO’s Very Large Telescope have shown — against all expectations — that a majority of the stars studied simply did not get to this stage in their lives at all. The international team found that the amount of sodium in the stars was a very strong predictor of how they ended their lives.

The way in which stars evolve and end their lives was for many years considered to be well understood. Detailed computer models predicted that stars of a similar mass to the Sun would have a period towards the ends of their lives — called the asymptotic giant branch, or AGB — when they undergo a final burst of nuclear burning and puff off a lot of their mass in the form of gas and dust.

But when Australian stellar theory expert Simon Campbell of the Monash University Centre for Astrophysics, Melbourne, scoured old papers he found tantalising suggestions that some stars may somehow not follow the rules and might skip the AGB phase entirely. He takes up the story:

“For a stellar modelling scientist this suggestion was crazy! All stars go through the AGB phase according to our models. I double-checked all the old studies but found that this had not been properly investigated. I decided to investigate myself, despite having little observational experience.”

Full Story: http://www.eso.org/public/news/eso1323/

Rounded Stones On Mars Evidence Of Flowing Water

Image Credit: NASA/JPL-Caltech

Observations by NASA’s Mars rover Curiosity have revealed areas with gravel and pebbles that are characteristic of a former riverbed. Researchers, including members of the Niels Bohr Institute, have analysed their shapes and sizes and the rounded pebbles clearly show that there has been flowing water on Mars. The results are published in the scientific journal, Science.

The Mars rover’s stereo camera took pictures of a few areas with densely packed pebbles, cemented together like concrete. The image field of an area named Hottah was a mosaic of approximately 1.4 meters x 80 centimeters. But when the picture is taken at an angle from the camera arm’s two meter high mast down towards the ground-level, it gives a slightly distorted view in which the size of the rocks depend on their location in the image frame. To remedy this, the researcher first had to process the image so the proportions are comparable.

“Next, we divided the image into smaller fields of 10 mm and analysed the gravel, which consists of coarse grains of sand around 1/3 mm. We examined the pebbles which are between 4 and 40 mm in greater detail. Altogether we made a thorough analysis of 515 pebbles”, explains Asmus Koefoed, research assistant in the Mars Group at the Niels Bohr Institute at the University of Copenhagen.

Full Story: http://www.nbi.ku.dk/english/news/news13/rounded-stones-on-mars-evidence-of-flowing-water/

Cassini Finds Hints Of Activity At Saturn Moon Dione

Image credit: NASA/JPL/Space Science Institute

From a distance, most of the Saturnian moon Dione resembles a bland cueball. Thanks to close-up images of a 500-mile-long (800-kilometer-long) mountain on the moon from NASA’s Cassini spacecraft, scientists have found more evidence for the idea that Dione was likely active in the past. It could still be active now.

“A picture is emerging that suggests Dione could be a fossil of the wondrous activity Cassini discovered spraying from Saturn’s geyser moon Enceladus or perhaps a weaker copycat Enceladus,” said Bonnie Buratti of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., who leads the Cassini science team that studies icy satellites. “There may turn out to be many more active worlds with water out there than we previously thought.”

Other bodies in the solar system thought to have a subsurface ocean – including Saturn’s moons Enceladus and Titan and Jupiter’s moon Europa – are among the most geologically active worlds in our solar system. They have been intriguing targets for geologists and scientists looking for the building blocks of life elsewhere in the solar system. The presence of a subsurface ocean at Dione would boost the astrobiological potential of this once-boring iceball.

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-178

Gemini Observatory Captures Comet ISON Hurtling Toward Uncertain Destiny With The Sun

A new series of images from Gemini Observatory shows Comet C/2012 S1 (ISON) racing toward an uncomfortably close rendezvous with the Sun. In late November the comet could present a stunning sight in the twilight sky and remain easily visible, or even brilliant, into early December of this year.

The time-sequence images, spanning early February through May 2013, show the comet’s remarkable activity despite its current great distance from the Sun and Earth. The information gleaned from the series provides vital clues as to the comet’s overall behavior and potential to present a spectacular show. However, it’s anyone’s guess if the comet has the “right stuff” to survive its extremely close brush with the Sun at the end of November and become an early morning spectacle from Earth in early December 2013.

On November 28, 2013, Comet ISON will make one of the closest passes ever recorded as a comet grazes the Sun, penetrating our star’s million-degree outer atmosphere, called the corona, and moving to within 800,000 miles (1.3 million km) of the Sun’s surface. Shortly before that critical passage, the comet may appear bright enough for expert observers using proper care to see it close to the Sun in daylight.

Full Story: http://www.gemini.edu/node/12006

Forecast For Titan: Wild Weather Could Be Ahead

Ligeia Mare, the second largest known body of liquid on Saturn’s moon Titan. Image credit: NASA/JPL-Caltech/ASI/Cornell

Saturn’s moon Titan might be in for some wild weather as it heads into its spring and summer, if two new models are correct. Scientists think that as the seasons change in Titan’s northern hemisphere, waves could ripple across the moon’s hydrocarbon seas, and hurricanes could begin to swirl over these areas, too. The model predicting waves tries to explain data from the moon obtained so far by NASA’s Cassini spacecraft. Both models help mission team members plan when and where to look for unusual atmospheric disturbances as Titan summer approaches.

“If you think being a weather forecaster on Earth is difficult, it can be even more challenging at Titan,” said Scott Edgington, Cassini’s deputy project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We know there are weather processes similar to Earth’s at work on this strange world, but differences arise due to the presence of unfamiliar liquids like methane. We can’t wait for Cassini to tell us whether our forecasts are right as it continues its tour through Titan spring into the start of northern summer.”

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-170&cid=release_2013-170

Researchers Reveal Model Of Sun’s Magnetic Field

Image credit: NASA Solar Dynamics Observatory

Researchers at the Universities of Leeds and Chicago have uncovered an important mechanism behind the generation of astrophysical magnetic fields such as that of the Sun.

Scientists have known since the 18th Century that the Sun regularly oscillates between periods of high and low solar activity in an 11-year cycle, but have been unable to fully explain how this cycle is generated.

In the ‘Information Age’, it has become increasingly important to be able to understand the Sun’s magnetic activity, as it is the changes in its magnetic field that are responsible for ‘space weather’ phenomena, including solar flares and coronal mass ejections. When this weather heads in the direction of Earth it can damage satellites, endanger astronauts on the International Space Station and cause power grid outages on the ground.

The research, published in the journal Nature, explains how the cyclical nature of these large-scale magnetic fields emerges, providing a solution to the mathematical equations governing fluids and electromagnetism for a large astrophysical body.

Full Story: http://www.leeds.ac.uk/news/article/3402/researchers_reveal_model_of_suns_magnetic_field

NASA’s WISE Mission Finds Lost Asteroid Family Members

Data from NASA’s Wide-field Infrared Survey Explorer (WISE) have led to a new and improved family tree for asteroids in the main belt between Mars and Jupiter.

Astronomers used millions of infrared snapshots from the asteroid-hunting portion of the WISE all-sky survey, called NEOWISE, to identify 28 new asteroid families. The snapshots also helped place thousands of previously hidden and uncategorized asteroids into families for the first time. The findings are a critical step in understanding the origins of asteroid families, and the collisions thought to have created these rocky clans.

“NEOWISE has given us the data for a much more detailed look at the evolution of asteroids throughout the solar system,” said Lindley Johnson, the program executive for the Near-Earth Object Observation Program at NASA Headquarters in Washington. “This will help us trace the NEOs back to their sources and understand how some of them have migrated to orbits hazardous to the Earth.”

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-179

New ET Detection Method Leads To Quest For World’s Largest Telescope

Until recently, one of the ultimate mysteries of the universe — how many civilizations may exist on planets orbiting other stars in the Milky Way Galaxy — relied on the possibility of detecting intelligent beings by radio signals. Now a team of astronomers, engineers, and physicists from the University of Hawaii, the University of Freiburg, and elsewhere has proposed a new and powerful technique to search for intelligent life.

The revolutionary method is described by four of the team’s astronomers in the June 2013 issue of Astronomy magazine, the world’s largest magazine on the subject, with a print and web readership of half a million each month. The story, “How to Find ET with Infrared Light,” was written by Jeff R. Kuhn of the University of Hawaii’s Institute for Astronomy, Svetlana V. Berdyugina of the University of Freiburg and the Kiepenheuer Institute for Solar Physics in Germany, David Halliday of Dynamic Structures, Ltd., in British Columbia, and Caisey Harlingten of the Searchlight Observatory Network in The Grange, Norwich, England.

Rather than looking for radio waves, the team suggests searching for the heat signatures of nearby planets, which requires a giant telescope that could detect infrared radiation directly from an exoplanet, thus revealing the presence of a civilization.

“The energy footprint of life and civilization appears as infrared heat radiation,” says Kuhn, the project’s lead scientist. “A convenient way to describe the strength of this signal is in terms of total stellar power that is incident on the host planet.” The technique arises from the fact that a civilization produces power that adds to the heat on a planet, beyond the heat received from its host star. A large enough telescope, idealized for infrared detection, could survey planets orbiting stars within 60 light-years of the Sun to see whether or not they host civilizations.

Astronomy Magazine Article (PDF): http://www.astronomy.com/~/media/Files/PDF/Magazine%20articles/ET-with-infrared-light.pdf

Herschel Space Observatory Finds Galaxy Mega Merger

Image credit: ESA/NASA/JPL-Caltech/UC Irvine/STScI/Keck/NRAO/SAO

A massive and rare merging of two galaxies has been spotted in images taken by the Herschel space observatory, a European Space Agency mission with important NASA participation.

Follow-up studies by several telescopes on the ground and in space, including NASA’s Hubble Space Telescope and Spitzer Space Telescope, tell a tale of two faraway galaxies intertwined and furiously making stars. Eventually, the duo will settle down to form one super-giant elliptical galaxy.

The findings help explain a mystery in astronomy. Back when our universe was 3 billion to 4 billion years old, it was populated with large reddish elliptical-shaped galaxies made up of old stars. Scientists have wondered whether those galaxies built up slowly over time through the acquisitions of smaller galaxies, or formed more rapidly through powerful collisions between two large galaxies.

The new findings suggest massive mergers are responsible for the giant elliptical galaxies.

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-171
Also: http://news.uci.edu/press-releases/fragile-mega-galaxy-is-missing-link-in-history-of-cosmos/
Also: http://keckobservatory.org/news/fragile_mega_galaxy_is_missing_link_in_history_of_cosmos