TITAN, A MOON OF SATURN

Orbiting Saturn are at least 60 confirmed moons. Most of these moons are quite small, and are irregularly shaped like asteroids, similar to the two moons of Mars. However, 1,221,860 kilometres away from Saturn is the second biggest moon in the Solar System: Titan. This moon is 5,150 kilometres wide, so it is bigger than Pluto and Mercury and would be classed as a planet if it orbited the Sun and not Saturn. Only Ganymede, one of Jupiter's moons, is bigger at 5,268 kilometres wide. Titan is an extremely interesting moon. It is the only moon in the Solar System to have a substantial atmosphere. This atmosphere is thicker than the atmospheres of Mars and Earth. What is most important though are the contents of Titan's atmosphere. It is made up mainly of nitrogen. The only other place to have an atmosphere containing mostly nitrogen is Earth! Also contained in Titan's atmosphere are hydrocarbon elements. These hydrocarbon elements are what makes the atmosphere appear an orange colour. One of the hydrocarbon molecules (hydrogen cyanide), when it is combined with nitrogen, forms amino acids. Amino acids are the building blocks of life! Scientists believe that Titan is a moon which resembles Earth before life began. Any water on the moon will be frozen because the temperature is -178°c. However, in millions of years, when the Sun begins to use up its supply of hydrogen and become a giant, eating up some of the Inner Planets, it will get closer to Saturn. This will heat up the planet and its surrounding moons. Frozen water could possibly melt and become liquid, allowing life-providing molecules to flow around easily. Perhaps Titan will become the future Earth!

So far, we have not seen Titan's surface. Its atmosphere is thicker than Earth's and prevented the space probe Voyager from looking through it when it visited the moon in 1980. But, in 1997, NASA launched Cassini, a spacecraft designed to visit Saturn. During its visit there, it will also take a look at Titan using special imaging equipment like the equipment used by Magellan to see Venus' surface through its thick atmosphere between 1990 and 1994. It will arrive there in Summer 2004 and, later that year, release a probe called Huygens into Titan's atmosphere and onto the surface (shown in the pictures above). This should help us to understand much more about the moon, allowing us to find out what the landscape is like, whether it shows any more signs of possibly containing life in the distant future, and, if so, how life actually began on Earth.