The surfaces of Asteroid Itokawa, the Moon, Venus, Mars, Titan, and Earth. All images show a view of nearby rocks to the distant horizon. The amount of surface modification evident of each of the bodies increases roughly from left to right.

From the the rubble pile asteroid of Itokawa, the cratered plains of the moon, the volcanic basalts of Venus, the basalt filled craters of Mars, the eroded icy cobbles of Titan to the great oceans of Earth, a variety of surfaces in our solar system is represented.

(Source: annesastronomynews.com)

‘Tis the Season — for Plasma Changes at Saturn

Researchers working with data from NASA’s Cassini spacecraft have discovered one way the bubble of charged particles around Saturn — known as the magnetosphere — changes with the planet’s seasons. The finding provides an important clue for solving a riddle about the planet’s naturally occurring radio signal. The results might also help scientists better understand variations in Earth’s magnetosphere and Van Allen radiation belts, which affect a variety of activities at Earth, ranging from space flight safety to satellite and cell phone communications. 

Read More.

(Source: christinetheastrophysicist)

Morning Star

Dawn on Saturn is greeted across the vastness of interplanetary space by the morning star, Venus, in this image from NASA’s Cassini spacecraft.

Venus appears just off the edge of the planet, in the upper part of the image, directly above the white streak of Saturn’s G ring. Lower down, Saturn’s E ring makes an appearance, looking blue thanks to the scattering properties of the dust that comprises the ring. A bright spot near the E ring is a distant star.

(Source: ikenbot, via scinerds)

NASA Probe Gets Close Views of Large Saturn Hurricane

NASA’s Cassini spacecraft has provided scientists the first close-up, visible-light views of a behemoth hurricane swirling around Saturn’s north pole.

In high-resolution pictures and video, scientists see the hurricane’s eye is about 1,250 miles (2,000 kilometers) wide, 20 times larger than the average hurricane eye on Earth. Thin, bright clouds at the outer edge of the hurricane are traveling 330 mph(150 meters per second). The hurricane swirls inside a large, mysterious, six-sided weather pattern known as the hexagon.

“We did a double take when we saw this vortex because it looks so much like a hurricane on Earth,” said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. “But there it is at Saturn, on a much larger scale, and it is somehow getting by on the small amounts of water vapor in Saturn’s hydrogen atmosphere.”

Scientists will be studying the hurricane to gain insight into hurricanes on Earth, which feed off warm ocean water. Although there is no body of water close to these clouds high in Saturn’s atmosphere, learning how these Saturnian storms use water vapor could tell scientists more about how terrestrial hurricanes are generated and sustained.

Both a terrestrial hurricane and Saturn’s north polar vortex have a central eye with no clouds or very low clouds. Other similar features include high clouds forming an eye wall, other high clouds spiraling around the eye, and a counter-clockwise spin in the northern hemisphere.

A major difference between the hurricanes is that the one on Saturn is much bigger than its counterparts on Earth and spins surprisingly fast. At Saturn, the wind in the eye wall blows more than four times faster than hurricane-force winds on Earth. Unlike terrestrial hurricanes, which tend to move, the Saturnian hurricane is locked onto the planet’s north pole. On Earth, hurricanes tend to drift northward because of the forces acting on the fast swirls of wind as the planet rotates. The one on Saturn does not drift and is already as far north as it can be.

“The polar hurricane has nowhere else to go, and that’s likely why it’s stuck at the pole,” said Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Hampton, Va.

Scientists believe the massive storm has been churning for years. When Cassini arrived in the Saturn system in 2004, Saturn’s north pole was dark because the planet was in the middle of its north polar winter. During that time, the Cassini spacecraft’s composite infrared spectrometer and visual and infrared mapping spectrometer detected a great vortex, but a visible-light view had to wait for the passing of the equinox in August 2009. Only then did sunlight begin flooding Saturn’s northern hemisphere. The view required a change in the angle of Cassini’s orbits around Saturn so the spacecraft could see the poles.

“Such a stunning and mesmerizing view of the hurricane-like storm at the north pole is only possible because Cassini is on a sportier course, with orbits tilted to loop the spacecraft above and below Saturn’s equatorial plane,” said Scott Edgington, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “You cannot see the polar regions very well from an equatorial orbit. Observing the planet from different vantage points reveals more about the cloud layers that cover the entirety of the planet.”

Cassini changes its orbital inclination for such an observing campaign only once every few years. Because the spacecraft uses flybys of Saturn’s moon Titan to change the angle of its orbit, the inclined trajectories require attentive oversight from navigators. The path requires careful planning years in advance and sticking very precisely to the planned itinerary to ensure enough propellant is available for the spacecraft to reach future planned orbits and encounters.

Image credit: NASA/JPL-Caltech/SSI

(Source: spaceplasma)

NASA Probe Observes Meteors Colliding with Saturn’s Rings.

“NASA’s Cassini spacecraft has provided the first direct evidence of small meteoroids breaking into streams of rubble and crashing into Saturn’s rings. 

These observations make Saturn’s rings the only location besides Earth, the moon and Jupiter where scientists and amateur astronomers have been able to observe impacts as they occur. Studying the impact rate of meteoroids from outside the Saturnian system helps scientists understand how different planet systems in our solar system formed. 

The solar system is full of small, speeding objects. These objects frequently pummel planetary bodies. The meteoroids at Saturn are estimated to range from about one-half inch to several yards (1 centimeter to several meters) in size. It took scientists years to distinguish tracks left by nine meteoroids in 2005, 2009 and 2012. 

Results from Cassini have already shown Saturn’s rings act as very effective detectors of many kinds of surrounding phenomena, including the interior structure of the planet and the orbits of its moons. For example, a subtle but extensive corrugation that ripples 12,000 miles (19,000 kilometers) across the innermost rings tells of a very large meteoroid impact in 1983.”

Read more…

(Source: thescienceofreality, via thescienceofreality)

Titan in “Methanovision”

Methanovision composite of Titan assembled from Cassini raw images taken on August 25, 2009.

White areas correspond to areas with more methane absorbtion (less haze) and red-brown area correspond to areas with more haze (north polar hood).

Image is an RGB composite from images in taken with the CB3 CL1, CL1 BL1, and inverted image of the MT3 CL2 filters respectively. Channel mixing was done as well as contrast enhancement and stretching of the original images prior to loading them into the RGB channels. The bright blue crescent is a processing artifact.

North is located toward that top. The “Playboy Peninsula” of the Senkyo-Aztlan margin is at center.

Image credits: NASA/JPL/Mike Malaska

(Source: ikenbot, via ikenbot)

pappubahry:

Enceladus, lit by the light reflected off Saturn’s rings.  Photographed by Cassini.

lunalotus:

Have you ever thought about how we’re tiny organic beings, floating on a huge piece of mass, in nothing ? And that same nothing (space) extends to as far as infinity as we can understand. It’s incomprehensible and it keeps me grounded. Everything else is simply trivial.

atomstargazer:

As winter approaches, Titan’s south pole gets an ice cloud

Seasonal change on Saturn’s large moon, Titan, is creating new cloud patterns at Titan’s south pole. The image just below shows the south pole of Titan in natural color. Look toward the bottom of the image, for a vortex. NASA reported on this vortex over Titan’s pole in July 2012 and said then it was a sign that autumn and ultimately winter were on their way to Titan’s southern hemisphere. Then yesterday (April 11, 2013), NASA said that an ice cloud, detectable only at infrared wavelengths, also has formed over Titan’s south pole.

Titan’s north pole also has an ice cloud, according to observations made since at least 2006 by NASA’s Cassini spacecraft (it has been orbiting Saturn, moving among Saturn’s moon since 2004). No one knows yet what sort of ice is in the cloud, whether it might be water, or perhaps more likely frozen methane. The northern ice cloud is now fading, NASA says. Since the northern ice cloud was seen during northern hemisphere winter on Titan, it’s logical to assume it’s a wintertime phenomenon. Now the seasons on Titan are changing, and winter is coming to the opposite part of Titan’s globe. It’s no surprise, then, that NASA is now seeing signs of a southern ice cloud.

The ice cloud taking shape over Titan’s south pole is setting off what NASA called “a cascade of radical changes in the atmosphere of Saturn’s largest moon.” It’s evidence that an important pattern of global air circulation on Titan has reversed direction. Donald E. Jennings, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland and lead author of the recent study of Titan’s southern ice cloud, said:

We associate this particular kind of ice cloud with winter weather on Titan, and this is the first time we have detected it anywhere but the north pole.

Read more from NASA about the ice cloud over Titan’s south pole

Image 1| This image a combination of red, green and blue images taken by the wide-angle camera on NASA’s Cassini spacecraft. It shows the vortex in Titan’s southern hemisphere. Recently, an ice cloud (visible only via infrared) has also formed over this pole. Image via NASA

Image 2 | A closer look at Titan’s south pole vortex. The vortex is a sign of winter ahead for Titan’s southern hemisphere, and so is the recently discovered ice cloud.

Image 3 | Until recently, only Titan’s north pole was known to have an ice cloud. It was winter in the northern hemisphere of Titan when the Cassini spacecraft first observed the ice cloud. This image – acquired in December 2006 – shows the north pole of Titan at infrared wavelengths. The presence of an ice cloud there had been predicted by Global Circulation Models of Titan’s atmosphere. Now Titan’s south pole is showing signs of having an ice cloud, as winter there approaches. Image via Laboratoire de Planétologie et Géodynamique de Nantes.

pennyfournasa:

On May 23rd NASA’s Cassini spacecraft, in orbit around Saturn since 2004, will make it’s 91st flyby of Saturn’s largest moon, Titan. Flying within 602 miles of the Titan’s surface, Cassini will use synthetic radar aperture techniques to make altimetry observations of the moon’s surface. This…

electricspacekoolaid:

Saturn’s Ring System Rains Water into Atmosphere 

NASA funded observations on the W. M. Keck Observatory with analysis led by the University of Leicester, England tracked the “rain” of charged water particles into the atmosphere of Saturn and found the extent of the ring-rain is far greater, and falls across larger areas of the planet, than previously thought. The work reveals the rain influences the composition and temperature structure of parts of Saturn’s upper atmosphere.

“Saturn is the first planet to show significant interaction between its atmosphere and ring system,” said James O’Donoghue, the paper’s lead author and a postgraduate researcher at Leicester. “The main effect of ring rain is that it acts to ‘quench’ theionosphereof Saturn, severely reducing the electron densities in regions in which it falls.”

O’Donoghue said the ring’s effect on electron densities is important because it explains why, for many decades, observations have shown electron densities to be unusually low at some latitudes at Saturn.

Read

ikenbot:

Spying on Senkyo

The Cassini spacecraft peers through Titan’s thick clouds to spy on the region dubbed “Senkyo” by scientists.

Credit: NASA/JPL-Caltech/Space Science Institute

The dark features include vast fields of dunes, composed of solid hydrocarbon particles precipitated out of Titan’s atmosphere. And Titan’s southern pole is shrouded in the recently formed polar vortex.

framesandflames:

False-color image of Saturn’s Atmosphere

Methane is represented here by Blue and Green.

Images from Cassini/SSI/NASA images taken on Feb 28th

Processed by me on flickr

pappubahry:

Polar vortex on Saturn, photographed by Cassini, 27 November 2012.  See also a processed version by Kevin McAbee at Emily Lakdawalla’s blog, where the effect of Saturn’s rotation and the camera’s perspective are corrected for.

expose-the-light:

Saturn’s Wispy F Ring