It was on 25 December 2004, when ESA’s Huygens probe unhitched itself from its mothership Cassini and took the unknown plunge towards the icy atmosphere of Titan, its final destination. It arrived on Titan on January 14, 2005. During its descent through the murky atmosphere of Titan, it started transmitting data to Cassini four minutes into its descent. When it finally landed in a slushy land, it was the first time a probe had landed on any extraterrestrial world in the outermost edges of the solar system where temperatures can plunge to minus three hundred degrees Celsius.
Titan was a fascinating place much akin to earth. There are clouds which surround the moon just like Earth, flowing rivers and lakes. It is the only known object in the universe which has a stable collection of liquids. But here the similarity ends. Titan has a surface temperature in the range of minus 300 degrees Celsius. The liquid which fills the lakes and rivers are hydrocarbons, mainly methane and ethane. Even then scientists do not speculate that life could have evolved under the ice where there is a possibility of liquid water.
With its mountains and rains, winds and waves, the Icy 3200 mile wide world is not desolate and dead like our Moon. And who knows beneath the liquid and oily layers of hydrocarbons there could be an ocean of water, and primitive life must be just starting.
The Cassini probe was primarily tasked with exploring Saturn and its moons, but the probe named after the famed Dutch Astronomer Christian Huygens helped us know a lot about what lay beneath the hazy clouds of Titan. Most of the knowledge about Titan was based indirectly. With Huygens, astronomers were able to know the exact conditions prevailing on the icy world first hand.
Measurements made by the probe helped scientists to understand the composition of Titan’s atmosphere in the past which must have been a combination of ammonia and methane. It will assist in understanding how these molecules behave in a predominantly nitrogen atmosphere. The conditions must be just akin to the condition on Earth before the evolution of life when oxygen became abundant.