UPSC Express

In focus: Titan

Introduction

• Titan is the only moon of Saturn that has a size comparable to that of our own moon.
• It is the second largest moon in our solar system after Ganymede of Jupiter.

Features

• Thick atmosphere
  • Titan is the only moon that has a thick atmosphere. (about 200 km)
  • The atmosphere is composed of 95% nitrogen, traces of methane, ethane, acetylene, ethylene and propane.
• Composition
  • As a result of high atmospheric pressure and low temperature (-178 degree Celsius), hydrocarbons such as methane, ethane exist as liquid on Titan.
  • As a result it is the only place other than earth that has standing liquid on its surface.

Cassini Mission and its findings

• Launched in 1997, reached Saturn in 2004
• Joint effort of NASA, European Space Agency and the Italian Space Agency.
• Final flyby in 2017.

Objectives

• Study of composition, structure, weather, origin and evolution of Saturn
• Structure and composition of Saturn’s rings
• Study of Titan and other small icy satellites of Saturn

Key discoveries

• Cassini spacecraft was the first to observe Titan to have rain, rivers, lakes and seas made of hydrocarbons.
• First to observe nitrogen-rich atmosphere.
• Current discovery
  • Titan’s northern hemisphere has lakes 300 ft deep made of methane.
  • The lakes are on top of landforms similar to mesas or butte on earth (flatlands) in Karst topography.
  • Further there are small shallow lakes (called phantom lakes) seasonal in nature that appear in winter and evaporate in summer.