MOON PROFILE TITAN

Saturn's biggest moon is a harsh, uninhabitable world, yet has uncanny similarities to our home planet

Titan is one of the most intriguing moons in our Solar System. From the outside astronomers sée a ball of golden-orange haze, but what's hiding beneath this atmosphere is what intrigues them - a freezing world with bodies of liquid. Planetary scientists are fascinated by Titan and its unusual contents. Titan, the largest moon of Saturn and the second-largest moon in the Solar System behind Jupiter's Ganymede, is an.. icy ball that stretches out to almost 5,150 kilometres (3,200 miles) in diameter, nearly 50 per cent wider than Earth's Moon. Due to Saturn's position in space, around 1.4 billion kilometres (870 million miles) from the Sun - nine times farther than Earth's average distance - its satellite Titan receives sunlight that is 100 times fainter than the light on Earth. This freezing world may be one that is inhospitable for humans, but its icy lakes are a close Earth analogue. These features have been the subject of many studies.

Though there are many interesting moons in the Solar System, Titan is the most Earth-like: it has an atmosphere and is rocky, but also has bodies of liquid on the surface with a rain cycle replenishing them. All of this happens on a moon that has a surface temperature of -179 degrees Celsius (-290 degrees Fahrenheit). Unlike Earth, there aren't lakes of water on Titan, as that would have been frozen. Instead, the lakes, rivers and seas are filled with liquid hydrocarbons such as methane and ethane. These complex molecules are capable of existing as liquids at such a cold temperature.