An orange layer of haze tops Saturn's moon Titan in this view from the Cassini spacecraft. The haze is a "smog" created by interactions between solar radiation and hydrocarbons in Titan's cold, dense atmosphere. Cassini's instruments have peered through the haze to show large lakes of liquid ethane and methane, dunes made of grains of ice, possible ice volcanoes, and many other features. [NASA/JPL/SSI]
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Through the Haze
The Cassini spacecraft has been exploring Saturn and its rings and moons for more than a decade. It’s revealed details that are impossible to see from Earth — from swirling vortexes at Saturn’s poles to geysers of water and ice at the south pole of one of the moons.
It’s given us especially sharp views of Saturn’s largest moon, Titan, which is bigger than the planet Mercury. It’s intriguing because it has a dense, cold, nitrogen-rich atmosphere that may resemble the atmosphere of the young Earth.
The atmosphere contains a lot of hydrocarbons — compounds like methane and ethane. They’re part of what makes Titan so intriguing. But they create an orange haze that blocks Titan’s surface from view.
Some of Cassini’s instruments look at wavelengths that can penetrate the haze. That’s provided the first good look at the surface of Titan.
Cassini’s images have revealed a world that looks much like the surface of Earth. They’ve shown us big lakes near Titan’s poles — filled not with water, but with ethane and methane. It’s also revealed riverbeds and other Earth-like features.
These observations tell us that Titan cycles liquids much like Earth does — the ethane and methane form clouds, fall as drizzle or rain, carve rivers, fill lakes, and evaporate back into the atmosphere.
In fact, Cassini has watched as a cloud system has formed over one of the lakes in Titan’s northern hemisphere in recent months. More about that tomorrow.
Script by Damond Benningfield, Copyright 2014
Today's program was made possible in part by a grant from the NASA Science Mission Directorate.
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