NASA's Cassini spacecraft recently spotted a gigantic ice cloud on Titan, one of Saturn's moons, according to a press release. Cassini has been exploring Titan's pole for the past few years, and the finding marks the first time that any spacecraft has discovered the onset of a Titan winter. The fact that this new cloud was found in the moon's lower stratosphere, where temperatures are colder, indicates a higher likelihood of a cold winter. 

"When we looked at the infrared data, this ice cloud stood out like nothing we've ever seen before," said Carrie Anderson of NASA's Goddard Space Flight Center in Greenbelt, Md. "It practically smacked us in the face."

The cloud was detected using Cassini's infrared instrument, which gathers profiles of Titan's atmosphere at invisible thermal wavelengths.

Scientists can use the size, altitude and composition of polar clouds to understand the nature and severity of coming winters on Titan.

"The opportunity to see the early stages of winter on Titan is very exciting," said Robert Samuelson, a Goddard researcher working with Anderson. "Everything we are finding at the south pole tells us that the onset of southern winter is much more severe than the late stages of Titan's northern winter."

Titan's unique atmosphere and environmental characteristics make it the focus of many research projects - it is currently the only world in the solar system aside from Earth that has a stable liquid on its surface, according to Discovery. This makes it a likely location for alien life, although any organisms that evolved on it would be much different than those on Earth due to the ethane and methane composition of its seas, according to Space.