Saturn System Moves Oxygen From Enceladus To Titan

by Laura Layton
Washington DC (SPX) Jul 05, 2010
Complex interactions between Saturn and its satellites have led scientists using NASA's Cassini spacecraft to a comprehensive model that could explain how oxygen may end up on the surface of Saturn's icy moon Titan. The presence of these oxygen atoms could potentially provide the basis for pre-biological chemistry.

The interactions are captured in two papers, one led by John Cooper and another led by Edward Sittler, published in the journal Planetary and Space Science in late 2009. Cooper and Sittler are Cassini plasma spectrometer team scientists at NASA's Goddard Space Flight Center in Greenbelt, Md.

"Titan and Enceladus, another icy moon of Saturn, are chemically connected by the flow of material through the Saturn system," Cooper said.

In one paper, Cooper and colleagues provide an explanation for forces that could generate the Enceladus geysers that spew water vapor into space. In the other, published in the same issue, Sittler and colleagues describe a unique new process in which oxygen that circulates in the upper atmosphere of Titan can be carried all the way to the surface without further chemical contamination by being encased in carbon cages called fullerenes.

The work draws upon previous work by Sittler and others that model the dynamics of how particles, including water molecules, travel from Enceladus to Titan. At Enceladus the flow process begins with what they call the "Old Faithful" model, after the Old Faithful geyser in Yellowstone National Park.

In this model, gas pressure slowly builds up inside Enceladus, then gets released occasionally in geyser-like eruptions.

Unlike terrestrial geysers, or even geyser-like forces on Jupiter's moon Io, the model proposed by Cooper shows that charged particle radiation raining down from Saturn's magnetosphere can create the forces from below the surface that are required to eject gaseous jets.

Energetic particles raining down from Saturn's magnetosphere - at Enceladus, mostly electrons from Saturn's radiation belts - can break up molecules within the surface.

This process is called radiolysis. Like a process called photolysis, in which sunlight can break apart molecules in the atmosphere, energetic radiation from charged particles that hit an icy surface, like that of Enceladus, can cause damage to molecules within the ice.

These damaged molecules can get buried deeper and deeper under the surface by the perpetual churning forces that can repave the icy surface. Meteorites constantly crashing into the surface and splashing out material might also be burying the molecules.

www.spacedaily.com

Solar power could create fuel for cars

disclaimer: image is for illustration purposes only

by Staff Writers
Albuquerque (UPI) Jul 2, 2010
Carbon dioxide in the atmosphere could soon be used to create fuel to drive the word's cars and trucks, a U.S. researcher says.

Solar-powered technology could be used to "photosynthesize" hydrocarbon fuels that present-day vehicles could run on without major modifications, The Daily Telegraph reported Friday.

Solar reactors can take carbon dioxide and turn it into carbon monoxide and can also turn water into hydrogen and oxygen.

The results can react with a catalyst to form hydrocarbon fuels, in a technique known as the Fischer-Tropsch process.

Tests have been conducted with solar reactors in New Mexico and Zurich, Switzerland.

Using solar energy to create usable fuel is a possible way to satisfy the world's energy demands while minimizing carbon emissions, Ken Caldeira of the Carnegie Institution told Britain's New Scientist magazine.

"This area holds out the promise for technologies that can produce large amounts of carbon-neutral power at affordable prices, which can be used where and when that power is needed," he said.

www.solardaily.com

Opportunity Keeps On Driving To Endeavour Crater

by Staff Writers
Pasadena CA (JPL) Jul 05, 2010
Opportunity continues to make good progress toward Endeavour crater as solar energy levels improve.

On Sol 2281 (June 24, 2010), the rover completed over 70 meters (230 feet), driving east/southeast.

On Sol 2283 (June 26, 2010), the rover headed 57 meters (187 feet) to the northeast to avoid some large ripples.

The rover drove again on Sol 2286 (June 29, 2010), covering over 70 meters (230 feet) to the east.

As of Sol 2286 (June 29, 2010), solar array energy production has improved to 354 watt-hours, atmospheric opacity (Tau) was 0.295 and the solar array dust factor is 0.577.

Total odometry is 21,408.21 meters (21.41 kilometers, or 13.30 miles).

www.marsdaily.com

CID-42: A Black Hole 'Slingshot'

Credits: X-ray: NASA/CXC/SAO/F.Civano et al. Optical: NASA/STScI

by Staff Writers
Washington DC (SPX) Jul 02, 2010
Evidence for a recoiling black hole has been found using data from the Chandra X-ray Observatory, XMM-Newton, the Hubble Space Telescope (HST), and several ground-based telescopes. This black hole kickback was caused either by a slingshot effect produced in a triple black hole system, or from the effects of gravitational waves produced after two supermassive black holes merged a few million years earlier.

The discovery of this object, located in this composite image, comes from a large, multi-wavelength survey, known as the Cosmic Evolution Survey (COSMOS).

This survey includes data from Chandra, HST, XMM- Newton, as well as ground-based observatories. Of the 2,600 X-ray sources found in COSMOS, only one - named CID-42 and located in a galaxy about 3.9 billion light years away - coincides with two very close, compact optical sources (The two sources are seen in the HST data, but they are too close for Chandra to resolve separately.) In this image, the X-ray source detected by Chandra is colored blue, while the Hubble data are seen in gold.

The galaxy's long tail suggests that a merger between galaxies has occurred relatively recently, only a few million years earlier. Data from the Very Large Telescope and the Magellan telescope give evidence that the difference in speed of the two optical sources is at least three million miles an hour.

The X-ray spectra from Chandra and XMM-Newton provide extra information about CID-42. Absorption from iron-rich gas shows that gas is moving rapidly away from us in the rest frame of the galaxy. This could be gas in the galaxy between us and one of the black holes that is falling into the black hole, or it could be gas on the far side of the black hole that is blowing away.

Taken together, these pieces of information allow for two different scenarios for what is happening in this system. In the first scenario, the researchers surmise that a triple black hole encounter was produced by a two-step process. First, a collision between two galaxies created a galaxy with a pair of black holes in a close orbit.

Before these black holes could merge, another galaxy collision occurred, and another supermassive black hole spiraled toward the existing black hole pair.

The interaction among the three black holes resulted in the lightest one being ejected. In this case, the optical source in the lower left of the image is an active galactic nucleus (AGN) powered by material being pulled along by, and falling onto, the escaping supermassive black hole.

The source in the upper right is an AGN containing the black hole that resulted from a merger between the two remaining black holes.

In this slingshot scenario, the high-speed X-ray absorption can be explained as a high-speed wind blowing away from the AGN in the upper right that absorbs light from the AGN in the lower left.

Based on its optical spectrum, the AGN in the upper right is thought to be obscured by a torus of dust and gas. In nearly all cases a wind from such an AGN would be undetectable, but here it is illuminated by the other AGN, giving the first evidence that fast winds exist in obscured AGN.

An alternative explanation posits a merger between two supermassive black holes in the center of the galaxy. The asymmetry of the gravitational waves emitted in this process caused the merged black hole to be kicked away from the center of the galaxy.

In this scenario, the ejected black hole is the point source in the lower left and a cluster of stars left behind in the center of the galaxy is in the upper right. The observed X-ray absorption would be caused by gas falling onto the recoiling black hole.

Future observations may help eliminate or further support one of these scenarios. A team of researchers led by Francesca Civano and Martin Elvis of the Harvard-Smithsonian Center for Astrophysics (CfA) will publish their work on CID-42 in the July 1st edition of The Astrophysical Journal.

The second scenario, concerning the recoil of a supermassive black hole caused by a gravitational wave kick, has recently been proposed by Peter Jonker from the Netherlands Institute for Space Research in Utrecht as a possible explanation for a source in a different galaxy.

In this study, led by Peter Jonker from the Netherlands Institute for Space Research in Utrecht, a Chandra X-ray source was discovered about ten thousand light years, in projection, away from the center of a galaxy. Three possible explanations for this object are that it is an unusual type of supernova, or an ultraluminous X- ray source with a very bright optical counterpart or a recoiling supermassive black hole resulting from a gravitational wave kick.

www.spacedaily.com

Next Mars Rover Sports A Set Of New Wheels

by Staff Writers
Pasadena CA (JPL) Jul 02, 2010
NASA's next Mars rover, Curiosity, is sitting pretty on a set of spiffy new wheels that would be the envy of any car show on Earth.

The wheels and a suspension system were added this week by spacecraft technicians and engineers. These new and important touches are a key step in assembling and testing the flight system in advance of a planned 2011 launch.

Curiosity, centerpiece of NASA's Mars Science Laboratory mission, is a six-wheeler and uses a rocker-bogie suspension system like its smaller predecessors: Spirit, Opportunity and Sojourner.

Each wheel has its own drive motor, and the corner wheels also have independent steering motors. Unlike earlier Mars rovers, Curiosity will also use its mobility system as a landing gear when the mission's rocket-powered descent stage lowers the rover directly onto the Martian surface on a tether in August 2012.

In coming months at NASA's Jet Propulsion Laboratory, the mobility system will get functional testing and be part of environmental testing of the rover.

The mobility system will now stay on Curiosity through launch unless testing identifies a need for rework that would require it to be disassembled.

The mission will launch from Florida during the period Nov. 25 to Dec. 18, 2011. Curiosity will examine an area of Mars for modern or ancient habitable environments, including any that may have also been favorable for preserving clues about life and environment, though this mission will not seek evidence of life.

It will examine rocks, soil and atmosphere with a diverse payload of tools, including a laser to vaporize patches of rock from a distance and an instrument designed to test for organic compounds.

www.marsdaily.com

Next Stop, Titan: Looking At The Land o' Lakes

Artist's concept of Cassini's June 4, 2010, flyby of Saturn's moon Titan. Image credit: NASA/JPL

by Staff Writers
Pasadena CA (JPL) Jun 07, 2010
NASA's Cassini spacecraft

will be eyeing the north polar region of Saturn's moon Titan this weekend, scanning the moon's land o' lakes.

At closest approach on early morning Saturday, June 5 UTC, which is Friday afternoon, June 4 Pacific time, Cassini will glide to within about 2,000 kilometers (1,300 miles) of the Titan surface.

Cassini will make infrared scans of the north polar region, which was in darkness for the first several years of Cassini's tour around the Saturn system. The lighting has improved as northern spring has started to dawn over the area.

The visual and infrared spectrometer

will be prime during closest approach, but the imaging science subsystem cameras will also be taking pictures. Among the scientific bounties, Cassini team members are hoping to get another good look at Kraken Mare, the largest lake on Titan, which covers a greater area than the Caspian Sea on Earth.

Although this latest flyby is dubbed "T69," planning changes early in the orbital tour made this the 70th targeted flyby of Titan.

/www.spacedaily.com

R Coronae Australis: A Cosmic Watercolour

by Staff Writers
Paris, France (SPX) Jul 01, 2010
This magnificent view of the region around the star R Coronae Australis was created from images taken with the Wide Field Imager (WFI) at ESO's La Silla Observatory in Chile. R Coronae Australis lies at the heart of a nearby star-forming region and is surrounded by a delicate bluish reflection nebula embedded in a huge dust cloud. The image reveals surprising new details in this dramatic area of sky.

The star R Coronae Australis lies in one of the nearest and most spectacular star-forming regions. This portrait was taken by the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. The image is a combination of twelve separate pictures taken through red, green and blue filters.

This image shows a section of sky that spans roughly the width of the full Moon. This is equivalent to about four light-years at the distance of the nebula, which is located some 420 light-years away in the small constellation of Corona Australis (the Southern Crown). The complex is named after the star R Coronae Australis, which lies at the centre of the image.

It is one of several stars in this region that belong to the class of very young stars that vary in brightness and are still surrounded by the clouds of gas and dust from which they formed.

The intense radiation given off by these hot young stars interacts with the gas surrounding them and is either reflected or re-emitted at a different wavelength.

These complex processes, determined by the physics of the interstellar medium and the properties of the stars, are responsible for the magnificent colours of nebulae. The light blue nebulosity seen in this picture is mostly due to the reflection of starlight off small dust particles.

The young stars in the R Coronae Australis complex are similar in mass to the Sun and do not emit enough ultraviolet light to ionise a substantial fraction of the surrounding hydrogen. This means that the cloud does not glow with the characteristic red colour seen in many star-forming regions.

The huge dust cloud in which the reflection nebula is embedded is here shown in impressively fine detail. The subtle colours and varied textures of the dust clouds make this image resemble an impressionist painting. A prominent dark lane crosses the image from the centre to the bottom left. Here the visible light emitted by the stars that are forming inside the cloud is completely absorbed by the dust.

These objects could only be detected by observing at longer wavelengths, by using a camera that can detect infrared radiation.

R Coronae Australis itself is not visible to the unaided eye, but the tiny, tiara-shaped constellation in which it lies is easily spotted from dark sites due to its proximity on the sky to the larger constellation of Sagittarius and the rich star clouds towards the centre of our own galaxy, the Milky Way.

www.spacedaily.com