ICY SCIENCE: SCIENCE SPACE ASTRONOMY Spring 2014 | Page 45

TITAN

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Saturn’s largest moon and the solar systems second largest moon is a unique satellite.
Firstly, and strangely, Titan has a thick and dense atmosphere. Strange? Well a body of
Titan’s mass, usually down to its gravity and the solar winds losses its atmosphere, as
did Mars. Mars is a similar size to Titan. However it is all about Location, Location. Saturn
orbits in a cold part of the solar system, so due to less influence from the sun Titan is
able to hold onto its gases.
A planet or moons ability to retain an atmosphere is determined by its mass and temperature. Titan is cold so therefore its atmosphere gas molecules move slowly and not fast
enough to escape Titan’s gravity. It may lose Hydrogen molecules because they are far
lighter. Titan also never became hot when it formed, this enabled methane, ammonia and
water ice to form on its surface. Water remained on its surface locked in ice . A mixture
of ammonia and methane then formed the moons early atmosphere.
Today the atmosphere is nitrogen rich.
By a method called photochemistry, solar radiation broke down the ammonia (NH3) into
Nitrogen (N2). .The conversion of NH3 to N2 occurs between 250 and 150K and lasted
for a period of about 100 million years.

The Surface
Titan’s surface temperature is a chilly -178 degrees C (-280 F), water on Titan becomes
rock like. However a liquid flows on the surface, this liquid is methane.

ICY SCIENCE | QTR 2 SPRING 2014