Saturn’s moon Titan keeps its secrets under a red, hazy atmosphere 1,221,850 kilometres from the ringed gas giant. Bigger than the planet Mercury, Titan is one of the most mysterious places in the solar system, full of organic chemistry that has similarities to the primitive Earth just as life was emerging billions of years ago. Titan might share some similarities with Earth, but Titan is as alien a world as you could imagine. Strange orange clouds, dark lakes and ponds, mountains, weird water volcanoes, and Saturn gracing the sky. This moon is extremely unique and we are just scratching the surface of this strange place. Rivaling the moons of Jupiter, Titan is more like a planet than a moon.
Titan is very active and dynamic and has weather like Earth, but different. It rains on Earth and it rains on Titan too…on Earth we have the water cycle, on Titan it’s the methane cycle. On Earth methane exists only as a gas, on Titan water is hard as rock. Exactly the same processes go on, streams, rivers, rain, clouds, erosion, but the materials involved are very different.
Titan is very cold (-179 degrees C) so cold that methane condenses into a liquid and forms orange clouds that drift through the atmosphere. Rivers and streams of methane tumble through valleys into lakes surrounded by shorelines, on these shorelines rims of material have been seen which suggest evaporation. Titan is the only body outside the Earth where bodies of liquid are known to exist on the surface. We cannot see the surface very easily because of the thick atmosphere, but Nasa’s Cassini Spacecraft can cut through the haze and image the surface with its radar.
This photo on the right shows hydrocarbon lakes that surround Titan’s north pole, imaged by Cassini’s radar. The top section of the image measures about 260 miles by 93 miles. The smallest details are 500 metres (1,640 feet) across.
In this next image from Cassini a high area of land is visible on the right of the photo that has numerous drainage channels that flow down to a lower area on the left. This image was taken in June 2009 and covers an area of 208 by 179 miles.
The third image on the right from the Cassini mission shows a bright rough area on the left, which seems to be high ground that slopes down to a lake. The boundary looks very much like a shoreline with bay and inlets. This photo covers an area of Titan 109 miles by 205 miles.
In this strange but weirdly familiar landscape, raindrops might be more than twice the size of raindrops on Earth due to the dense atmosphere, and with its lower gravity those raindrops might fall 8 to 10 times slower out of the sky than on Earth, like slowly falling snowflakes. Waves on the edges of lakes or sea would move much slower too, crashing onto the shoreline in a slowed down version of an Earth seascape. The wind blows clouds through the orange sky, and forms dark hydrocarbon dunes that circle the equator. Titan’s dynamic surface is also shaped by lava flows, but not like any lava flow on Earth. Cryo-volcanoes on Titan erupt with a strange type of lava…not molton rock, but water lava. This cold water lava is made of water mixed with ammonia. This mixture lowers the freezing point of the water from zero degrees Celsius to something like -100 degrees Celsius. This strange water lava oozes down the flanks of the cryo-volcanoes like treacle, and solidifies. Canyons, rivers, valleys, large bodies of liquid, weather, Titan is the nearest place to Earth ever found. Amazingly scientists now believe Titan holds a subsurface of liquid water and ammonia 60 miles below the surface.
Titan is the only moon in the solar system with a thick atmosphere, which frustratingly almost completely hides the moon’s surface from orbiting spacecraft with a thick red haze. The atmosphere is 95% nitrogen, 3% methane,and the remaining is hydrogen and other hydrocarbons. The atmospheric pressure on Titan is 1.6 times that of Earth.
On January 14th 2005 Nasa’s Cassini Spacecraft released the European Space Agency’s Huygens Probe to Titan. During its 2.5 hour decent it parachuted through the thick atmosphere and landed on a flood plain on the surface of Titan. Luckily it landed with a bump and not a splash, as it would have disappeared to the bottom of a lake. Huygens managed to take measurements of the atmosphere and wind speeds as it descended, as well as pictures of Titan’s alien landscape showing obvious erosion by liquid. When it landed the image was a hazy flat landscape strew with round cobbles of water ice.
On its decent through the atmosphere the Huygens probe took some amazing pictures which resemble the landscape of Earth in appearance. This image on the right was taken by Hugens on it’s decent through the Titan sky, from a height of about 10 miles. It clearly shows an area of land on the left that is riddled with drainage channels that flow down to the shoreline of a darker area on the right that appears to be a lake.
This amazing photo to the left is a composite image taken by Huygens from a height of 5 miles. The upper part of the picture shows a high area of land that slopes steeply down to the shoreline of a lake. This land appers to be covered in streams or rivers that flow into the lake. Although Huygensjob is now finished, the Cassini Spacecraft continues to tour the Saturn system and Titan is high on its agenda.