The Surface of Titan

Titian in IRThis composite image was stitched together using infrared views of Saturn’s moon Titan taken by the Cassini spacecraft. They were acquired during the a flyby on last month. The spacecraft’s visual and infrared mapping spectrometer (VIMS) instrument took the pictures. In this false color image blue represents wavelengths centered at 1.3 µm, green represents 2.0 µm, and red represents 5.0 µm. Visible light centered around 0.5µm reveals nothing below Titan’s hazy atmosphere. The near-infrared wavelengths in this image allow Cassini’s vision to penetrate the haze.

Image Credit: NASA

Triple Crescent

Triple CrescentSaturn has many moons. The three shown here—Titan, Mimas, and Rhea—show marked contrasts in their surface features. Titan, Saturn’s largest moon and the largest moon in this image, appears fuzzy because we only see its clouds. Because Titan’s atmosphere refracts light around the moon, its crescent is wrapped just a little further around the moon than it would on an airless body. Rhea (upper left) appears rough because its icy surface is heavily cratered. A close inspection of Mimas, though difficult to see at this scale, would show surface irregularities because of its violent history.

Image Credit: NASA

One more thing … If it’s clear where you are this evening, go outside and look up in the western sky just after sunset. There’s a conjunction of Venus and Jupiter tonight. They will be separated by less than half the diameter of the Full Moon.

Titan—the Hard Way

Six Nightly Views of Titan's SurfaceWe’re used to seeing pictures of Saturn’s moon Titan taken by the Cassini spacecraft. These views of Titan were taken by a ground-base telescope, the Very Large Telescope at the European Southern Observatory in Chile. The image on the right has been enlarged for clarity, and the coordinate grid used Titan overlaid. The images are false-colour renderings coded with red (1.575 μm; surface), green (1.600 μm; surface), and blue (1.625 μm; atmosphere), respectively.

Image Credit: ESO

Ten Years Ago

Huygens_descentThese images of Saturn’s moon Titan were taken on 14 January, 2005 by the Huygens probe at four different altitudes. The images are flattened (Mercator) projections of the view from the descent imager/spectral radiometer on the probe as it landed on Titan’s surface.

Ten years ago, Huygens parachuted into the haze of the alien moon toward an uncertain fate. After a gentle descent lasting more than two hours, it landed with a thud on a frigid floodplain surrounded by icy cobblestones. This was the first landing on a moon in the outer solar system, Titan, the largest moon of Saturn.

Image Credit: ESA / NASA

Titan and Rhea

Titan and RheaSaturn’s two largest moons, Titan and Rhea, seem to be stacked together in this true-color picture taken by the Cassini spacecraft. This view looks toward the Saturn-facing side of Rhea. North on Rhea is up and rotated 35 degrees to the right.

Separate images taken with red, green and blue filters using Cassini‘s narrow-angle camera were combined to create this natural-color view. The spacecraft was approximately 1.8 million km away from Rhea and 2.5 million km from Titan.

Image Credit: NASA

Titan’s Southern Vortex

Titan_SouthernVortexThose of us who follow the Cassini mission are used to seeing pictures containing multiple moons of Saturn. That’s what I thought this was when I first saw it, but that small crescent isn’t a moon. It’s the storm vortex around Titan’s south pole. Its sunlit edge stands out distinctly against the darkness of the moon’s unilluminated hazy atmosphere. Cassini spacecraft images of the vortex have led scientists to conclude that its clouds form at a very high altitude—where the Sun has not yet set—above the surrounding haze near the moon’s surface.

Image Credit: NASA

The Seasons Change on Titan

Titan_IRThis false-color picture was assembled from infrared data collected by the Cassini spacecraft. It show the differences in the composition of surface materials around hydrocarbon lakes at Titan, Saturn’s largest moon. With the Sun now shining on Titan’s northern hemisphere, the weather will be changing, and Cassini will be watching.

Learn more here.

Image Credit: NASA

Not a Solar Eclipse

titanbusy_cassini_960No, it’s not a solar eclipse. It’s a picture of the rings and a couple of the moons of Saturn. The large object near the center is Titan, Saturn’s largest moon and one of the most interesting objects in the entire Solar System. The central dark spot is the body of the moon. The bright halo is atmospheric haze above Titan. The gases of the atmosphere scatter sunlight. Saturn’s rings are shown nearly edge on. Enceladus, a small moon, is at about 4 or 5 o’clock at the edge of Titan.

This image was taken with the Cassini spacecraft’s camera pointing almost directly at the Sun, so the surfaces of Titan and Enceladus appear in silhouette, and the rings of Saturn look like a photographic negative.

Image Credit: NASA

Titan’s Southern Sea

Titan_southern_seaOr what’s left of it. The red outline traces the ancient shoreline. The largest remaining lake in Titan’s southern hemisphere, Ontario Lacus appears as black within that basin. The black indicated that it is filled with liquid.

This picture is assembled from images was obtained by the Cassini spacecraft’s radar instrument during July, 2009, and January, 2010. Mission scientists estimate the ancient sea was possibly as large as 475 X 280 km across but probably only a few hundred meters deep. Ontario Lacus is about 80 X 235 km and probably on the order of 10 meters deep. Seas may have covered large parts of Titan’s southern hemisphere less than 50,000 years ago.

Titan, Saturn’s largest moon, is the only body in the Solar System other than the Earth that has large open bodies of liquid. The temperature on Titan runs around 94 K (about -290 °F), so that liquid is not water. It’s methane and ethane. While over one hundred lakes and three seas are seen around Titan’s north pole, the south pole only has a few small lakes. It’s been suggested that cycles similar to Milankovich cycles on Earth cause long-term transfers of liquid hydrocarbons between the poles and that it’s now the north poles turn to keep the bulk of the liquids. Less than 50,000 years ago, the cycle may have reversed, nearly emptying the southern seas.

Image Credit: NASA

Clouds on Titan

IDL TIFF fileUsing a filter sensitive to near infrared light (938 nm), the Cassini spacecraft peered through the haze in Titan’s equatorial region down to its surface. It also caught a vortex of clouds hovering over the moon’s south pole (just to the right of the terminator on the moon’s dark side). The lit terrain seen here is on the Saturn-facing hemisphere of Titan. North on Titan and rotated 11 degrees to the left of up in this picture.

Image Credit: NASA

A Reflection from Titan

titan_lake_flashThis image shows a flash of sunlight reflected off a lake on Titan, Saturn’s largest moon. Its northern hemisphere is shrouded in darkness for nearly 15 years, but the sun begins to illuminate the area again as it approaches its spring equinox. The Cassini spacecraft was able to detect the glint at the beginning of Titan’s spring in 2009. The moon’s hazy atmosphere scatters and absorbs many wavelengths of light, including most of the visible spectrum. But an onboard instrument was able to detect the glint in infrared wavelengths that can penetrate through Titan’s atmosphere. This image was created using wavelengths of light in the 5 µm range.

Image Credit: NASA


titan_surfaceNo, this isn’t a picture from Mars. It’s from Titan, Saturn’s largest moon. This view taken by the Huygens lander on the moon’s surface shows pebble-sized objects thought to be rocks or ice blocks. The two objects just below the middle of the image are about 150 mm and 40 mm across, respectively, and are about 840 mm from Huygens. The surface is darker than originally expected and made up of a mixture of water and hydrocarbon ice. There is also evidence of erosion at the base of the objects.

Image Credit: ESA/NASA

Titanic Craters

titan_cratersTitan is the only moon in the solar system with a thick atmosphere, and the only world besides Earth known to have lakes and seas on its surface. However, with a frigid surface temperature of around -290° F (94 K), the rain falling on Titan isn’t water. It’s liquid methane and ethane, compounds that are gases at room temperature on Earth.

Most of Saturn’s moons display their ancient faces pockmarked by thousands of craters. Titan, Saturn’s largest moon, looks younger than it really is because its craters are being eroded. Radar observations by the Cassini spacecraft show that dunes of hydrocarbon sand are filling in the craters.

This image taken with the Cassini radar shows two craters on Titan. On the left is crater Sinlap which is a relatively ‘fresh’ crater, with a depth-to-diameter ratio similar to is found on other large moons in the solar system such as Ganymede. One the right is Soi, an extremely eroded crater with a very small depth compared to similar craters on Ganymede. These craters are both about 80 km (almost 50 miles) in diameter.

Image Credit: NASA

Saturn, Titan, and Changing Seasons

This picture is a mosaic of six images—two each via red, green and blue spectral filters—combined to create this natural color view. The images were obtained with the Cassini spacecraft wide-angle camera on 6 May, 2012. The view looks toward the northern, sunlit side of the rings from just above the ring plane.

The giant moon Titan is silhouetted in front of Saturn as the planet is changing seasons. Titan, Saturn’s largest moon, measures 35,150 km across and is larger than the planet Mercury. It could have been a planet if it were on its own.

Saturn’s southern hemisphere, in its approach to winter, is taking on a bluish hue. This change seems to be caused by a reduced intensity of ultraviolet light. UV produces haze in Saturn’s atmosphere, and the increasing intensity of ultraviolet light in the hemisphere approaching summer causes the increase in haze. The presence of the ring shadow in the winter hemisphere enhances this effect. The reduction of smog and the consequent clearing of the atmosphere makes for a bluish hue. The presence of methane, which generally absorbs in the red part of the spectrum, in a now clearer atmosphere also enhances the blue. A different mechanism, the increased opportunity for direct scattering of sunlight by the molecules in the air, makes the sky blue, as on Earth.

Image Credit: NASA

Titan and Tethys

The Cassini spacecraft snapped this picture of a pair of Saturn’s moons, giant Titan beyond smaller Tethys. This view looks toward the Saturn-facing sides of the moons. Titan is about 5,150 km in diameter,  and Tethys is roughly 1,060 km across.

This picture was taken in visible green light with the spacecraft’s narrow-angle camera on in October, 2010. Titan is about 2.5 million km (2.5 Gm) from Titan. Tethys is only about1.5 million km away. If you click on the picture to embiggen the image, the scale is 15 km per pixel on Titan and 9 km per pixel on Tethys.

Image Credit: NASA

The Vortex of Titan

Something’s going on over the south pole of Titan. A vortex of haze appears to be forming, but no one can explain why. This natural-color image shows the light-colored vortex which was found on images taken last month when the Cassini spacecraft flew by the largest of Saturn’s moons. Cassini is now able to see the southern vortex because its orbit around Saturn was recently boosted out of the plane of the orbits of the rings and moons. Clues about the odd feature are being gathered, but it will soon be winter in the southern hemisphere of Titan. The vortex, if it lasts, will be in darkness for the next few years.

Image Credit: NASA

Moons and Rings

A brightly reflective Enceladus appears before Saturn’s rings, while the planet’s larger moon Titan lurks in the distance. Jets of water ice and vapor emanating from the south pole of Enceladus, which hint at subsurface sea rich in organics, and liquid hydrocarbons ponding on the surface on the surface of Titan make these two of the most fascinating moons in the Saturnian system.

Enceladus (504 km across) is in the center of the image. Titan (5,150 km across) shows up faintly in the background beyond the rings. This view looks toward the anti-Saturn side of Enceladus and the Saturn-facing side of Titan. The northern, sunlit side of the rings is seen from just above the ringplane.

The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on 12 March, 2012. The spacecraft was about 1 million km from Enceladus and at a Sun-Enceladus-spacecraft angle of 36 degrees.

Image Credit: NASA/JPL

Interplanetary Smog

This view looks toward the south pole of Titan, Saturn’s largest moon, and shows a depression within the moon’s orange and blue haze layers near the south pole.

The moon’s high altitude haze layer appears blue here; whereas, the main atmospheric haze is orange. The difference in color could be due to particle size of the haze. The blue haze likely consists of smaller particles than the orange haze. The depressed or attenuated layer appears in the transition area between the orange and blue hazes about a third of the way in from the left edge of the narrow-angle image. Titan’s south pole is in the upper right of this image.

Images taken by NASA’s Cassini spacecraft using red, green and blue spectral filters were combined to create this natural color view. The images were obtained on 11 September, 2011, at a distance of approximately 83,000 miles (134,000 kilometers) from Titan.

Image Credit: NASA/JPL

Titan and Dione

Saturn’s third-largest moon Dione can be seen through the haze of its largest moon, Titan, in this view of the two posing before the planet and its rings. This view looks toward the side of Titan (3200 miles, 5150 kilometers across) and Dione (698 miles, 1123 kilometers across) facing away from Satrun. North is up on the moons. This view looks toward the northern, sunlit side of the rings from just above the ring plane.

Images taken with the Cassini spacecraft narrow-angle camera using red, green and blue spectral filters were combined to create this natural color view.

Image credit: NASA/JPL