Using data collected by Cassini's Visual and Infrared Mapping Spectrometer, or VIMS, while observing Titan's sunsets, researchers created simulated spectra of Titan as if it were a planet transiting across the face of a distant star. The research helps scientists to better understand observations of exoplanets with hazy atmospheres.
Dione's large crater, Evander, appears here half in shadow, throwing its topography into sharp relief. Evander is centered at about 57 degrees South latitude, 145 degrees West longitude and can also be seen in the Dione south polar map featured in PIA12579 (see also PIA12728).
Lit terrain seen here is on the anti-Saturn hemisphere of Dione. North on Dione is up and rotated 25 degrees to the left. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on August 22, 2013.
The view was acquired at a distance of approximately 870,000 miles (1.4 million kilometers) from Dione. Image scale is 5 miles (8 kilometers) per pixel.
Astronomers using the NASA/ESA Hubble Space Telescope have captured new images of the dancing auroral lights at Saturn’s north pole. Taken in April and May 2013 from Hubble’s perspective in orbit around Earth, these observations provide a detailed look at previously unseen dynamics in the choreography of the auroral glow.
The ultraviolet images, taken by Hubble’s super-sensitive Advanced Camera for Surveys, capture moments when Saturn’s magnetic field is affected by bursts of particles streaming from the Sun.
Saturn’s magnetosphere – the vast magnetic ‘bubble’ that surrounds the planet – is compressed on the Sunward side of the planet, and streams out into a long ‘magnetotail’ on the nightside.
It appears that when particles from the Sun hit Saturn, the magnetotail collapses and later reconfigures itself, an event that is reflected in the dynamics of its auroras.
Saturn was caught during a very dynamic light show – some of the bursts of light seen shooting around Saturn’s polar regions traveled more than three times faster than the speed of the gas giant’s roughly 10-hour rotation period!
The new observations were taken as part of a three-year Hubble observing campaign, and are presented in a paper published in the journal Geophysical Research Letters. The images complement those taken by the international Cassini spacecraft orbiting Saturn.
Tethys' trailing side shows two terrains that tell a story of a rough past. To the north (up, in the image) is older, rougher terrain, while to the south is new material dubbed "smooth plains" by scientists.
The smooth plains are roughly antipodal to the large impact crater Odysseus. Odysseus, which is on the far side of Tethys (660 miles, or 1,060 kilometers across) from this perspective, is out of view. (See PIA12588 for a view of Odysseus.) It's thought that the impact that created Odysseus also created the smooth plains, although exactly how this happened is not yet clear.
This view looks toward the trailing hemisphere of Tethys. North on Tethys is up and rotated 2 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on November 27, 2013.
The view was obtained at a distance of approximately 1.1 million miles (1.8 million kilometers) from Tethys. Image scale is 7 miles (11 kilometers) per pixel.
The spokes in Saturn's rings continue to be active and Cassini scientists continue to study them in order to unravel their mysteries. The spokes, visible near the center of the image, appear bright against the dense core of the B ring, which is the darkest section of the rings shown here in silhouette. Conditions favorable to the production of spokes are expected to wane as Saturn approaches its northern summer solstice. Scientists are eager to monitor the transition, the timing of which could yield valuable insight into the mechanisms that form these intriguing and ethereal features.
This view looks toward the unilluminated side of the rings from about 47 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on October 19, 2013.
The view was acquired at a distance of approximately 1.2 million miles (1.9 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 122 degrees. Image scale is 72 miles (115 kilometers) per pixel.
Titan's south polar vortex mimics the moon itself, creating an elegant crescent within a crescent. Situated above the surrounding polar atmosphere, the raised walls along the sunward side of the vortex just catch the grazing sunlight, creating a crescent of its own. Titan (3,200 miles, or 5,150 kilometers across) is Saturn's largest moon and possesses a dense and dynamic atmosphere. For a color image of the south polar vortex on Titan, see PIA14919. For a movie of the vortex, see PIA14920.
This view looks toward the trailing hemisphere of Titan. North on Titan is up. The image was taken with the Cassini spacecraft wide-angle camera on December 1, 2013 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 939 nanometers.
The view was obtained at a distance of approximately 108,000 miles (174,000 kilometers) from Titan. Image scale is 6 miles (10 kilometers) per pixel.
This colorful cosmic rainbow portrays a section of Saturn’s beautiful rings, four centuries after they were discovered by Galileo Galilei.
Saturn’s rings were first observed in 1610. Despite using his newly created telescope, Galileo was confounded by what he saw: he referred to the peculiar shapes surrounding the planet as “Saturn’s children”. Only later did Christiaan Huygens propose that the mysterious shapes were actually rings orbiting the planet. These were named in the order in which they were discovered, using the first seven letters of the alphabet: the D-ring is closest to the planet, followed by C, B, A, F, G and E.
The data for this image, which shows the portion of the C-ring closest to Saturn on the left, with the B-ring beginning just right of center, were acquired by Cassini’s Ultraviolet Imaging Spectrograph, or UVIS, as the spacecraft entered into orbit around Saturn on 30 June 2004.
UVIS, as its name suggests, carries out observations in ultraviolet wavelengths. During the Saturn orbit insertion maneuver, when Cassini flew closest to the rings, UVIS could resolve features up to 97 km across. The region shown in this image spans about 10,000 km.
The variation in the color of the rings arises from the differences in their composition. Turquoise-hued rings contain particles of nearly pure water ice, whereas reddish rings contain ice particles with more contaminants.
Saturn’s prominent and complex ensemble of rings is the best studied in the Solar System, but it is still not known how the rings formed. One suggestion is that they formed at the same time as the planet and that they are as old as the Solar System. Another idea is that they formed when icy material was pulled from another body into Saturn’s gravitational field, in which case the rings could be younger than the planet.
One thing is sure: as Cassini searches for answers it is providing amazing images of these rainbow rings.
The Cassini–Huygens mission is a cooperative project of NASA, ESA and Italy’s ASI space agency.
This image was first published at the NASA Cassini website, in 2004.
This view from NASA's Cassini spacecraft features a blue planet, but unlike the view from July 19, 2013 (PIA17172) that featured our home planet, this blue orb is Uranus, imaged by Cassini for the first time.
Uranus is a pale blue in this natural color image because its visible atmosphere contains methane gas and few aerosols or clouds. Methane on Uranus -- and its sapphire-colored sibling, Neptune -- absorbs red wavelengths of incoming sunlight, but allows blue wavelengths to escape back into space, resulting in the predominantly bluish color seen here. Cassini imaging scientists combined red, green and blue spectral filter images to create a final image that represents what human eyes might see from the vantage point of the spacecraft.
Uranus has been brightened by a factor of 4.5 to make it more easily visible. The outer portion of Saturn's A ring, seen at bottom right, has been brightened by a factor of two. The bright ring cutting across the image center is Saturn's narrow F ring.
Uranus was approximately 28.6 astronomical units from Cassini and Saturn when this view was obtained. An astronomical unit is the average distance from Earth to the sun, equal to 93,000,000 miles (150,000,000 kilometers).
This view was acquired by the Cassini narrow-angle camera at a distance of approximately 614,300 miles (988,600 kilometers) from Saturn on April 11, 2014. Image scale at Uranus is approximately 16,000 miles (25,700 kilometers) per pixel. Image scale at Saturn's rings is approximately 4 miles (6 kilometers) per pixel. In the image, the disk of Uranus is just barely resolved. The solar phase angle at Uranus, seen from Cassini, is 11.9 degrees.
