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The brightest supernova

Scientists tell the story about a monstrous explosion, a hundred times more energetic than a typical supernova. Observations have been made by the Chandra spacecraft and ground telescopes.


STS-64: Free-flying EVA

Spacewalking astronauts flying untethered from shuttle Discovery as they tested a new safety jetpack was a visual highlight of STS-64.


Astronaut Hall of Fame

Veteran space shuttle fliers Mike Coats, Steve Hawley and Jeff Hoffman are inducted into the Astronaut Hall of Fame at Kennedy Space Center during this ceremony held May 5.

 Part 1 | Part 2

Traveling on Freedom 7

Fly with Alan Shepard during his historic journey into space with this documentary that takes the viewer along as an invisible companion to America's first astronaut.


Encounter with Jupiter

The Pluto-bound New Horizons spacecraft recently flew past the Jovian system for a gravity sling-shot toward the outer solar system. New images of Jupiter and its moons are revealed in this briefing.

 Presentation | Q&A

"The Time of Apollo"

This stirring 1970s documentary narrated by Burgess Meredith pays tribute to the grand accomplishments of Apollo as men left Earth to explore the Moon and fulfill President Kennedy's challenge to the nation.


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Saturn moon could yield new insight into origins of life
Posted: May 10, 2007

SAN ANTONIO -- Scientists have long known that the lower atmosphere of Saturn's moon Titan contains organic aerosols, or tholins, formed from simple organic molecules, such as methane and nitrogen. Researchers had assumed these tholins formed at altitudes of several hundred kilometers, but new information gathered by three particle spectrometers aboard the Cassini spacecraft shows tholin formation happens in Titan's atmosphere at altitudes greater than 1,000 kilometers. The results also show tholins form differently than previously thought.

Credit: Southwest Research Institute
Scientists at Southwest Research Institute (SwRI), the University of Kansas, University College London and The University of Texas at San Antonio report results of the observations in the paper "The Process of Tholin Formation in Titan's Upper Atmosphere," published in the May 11 issue of Science.

"Tholins are very large, complex organic molecules thought to include chemical precursors to life," said Dr. Hunter Waite, an Institute scientist in SwRI's Space Science and Engineering Division, and leader of Cassini's Ion Neutral Mass Spectrometer (INMS) team. "Understanding how they form could provide valuable insight into the origin of life in the solar system."

During Cassini's first encounters with Titan, the INMS revealed an atmosphere dominated by nitrogen and methane. Of significance from measurements taken in later flybys, however, was the detection of benzene, a critical component in the formation of aromatic hydrocarbon compounds. At the same time, two other Cassini sensors that are part of the Cassini Plasma Spectrometer (CAPS) investigation, the Ion Beam Spectrometer (IBS) and Electron Spectrometer (ELS), measured large positive and negative ions.

"The negative ions were a complete surprise," said Dr. David Young, also an SwRI Institute scientist, and leader of the CAPS investigation. "This suggests they may play an unexpected role in making tholins from carbon-nitrogen precursors."

"An additional surprising point is the large numbers of negative ions we see during Cassini's lowest flybys above the surface," said Dr. Andrew Coates, a researcher at the Mullard Space Science Laboratory, University College London. "This newly discovered, and important, population represents a highly significant proportion of the whole ionosphere at these locations."

"Our analysis suggests that the organic compounds are formed through ion-neutral chemical processes, which then give rise to the complex negative ions found by the ELS," Waite added.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

SwRI is an independent, nonprofit, applied research and development organization based in San Antonio, Texas, with more than 3,000 employees and an annual research volume of more than $455 million. Southwest Research Institute and SwRI are registered marks in the U.S. Patent and Trademark Office.