While Ottawa, recently the coldest capital on Earth, is barely out of winter solstice, Saturn’s largest moon just had April showers.
The aptly named Titan isn’t like other moons. It’s a cool moon. It has lakes and even rainfall at its polar latitudes.
In fact, Titan is so cool that it makes Ottawa look like southern Arizona during monsoon season.
Titan’s climate is so frigid that the only reason it has a water cycle is because it isn’t really water. The lakes and seas on Titan are made up mostly of methane, an organic compound known as a hydrocarbon due to its composition of hydrogen and carbon. Hydrocarbons have a much lower freezing temperature, allowing it to exist in a liquid state on Titan.
New research reveals numerous hydrocarbon wet spots had been discovered by the Cassini probe near the end of its 20-year stint. Saturn takes nearly 30 years to orbit the Sun, since it’s so far away. Thus, Saturn’s solstices, when its closest and furthest from the Sun, come every 14 years or so. Unlike Earth’s North pole, Titan is now facing the Sun.
Being so close to the Sun means winter is most certainly not coming for Titan’s North. All those methane lakes are vaporising and settling in the atmosphere—like water droplets condensing on the outside of a martini glass.
The scientists themselves liken it to a wet sidewalk. Much like a sidewalk drying up after a rainfall, wet spots on celestial bodies are visible because light reflects off them differently than the dryer parts. When scientists looked at some of the photos Cassini took, they could see literal soakage in the Moon’s North.
Methane is typically produced on Earth when buried micro-organisms reach depths so low that the heat and pressure turn the carbon dioxide into methane. This process is known as methanogenesis. Oil and gas companies use this information to find areas rich in natural gas.
While it would be wicked cool if that’s what wqas happening on Titan, it isn’t. Methane can be produced from regular old interactions between water and rock. In fact, Titan’s lack of oxygen is what leads researchers to believe that the climate runs on these hydrocarbons instead of water, which is made of oxygen and hydrogen. The lack of liquid water and frosty temperatures make a cold case for the possibility of extraterrestrial life.
That said, scientists do suspect that water does exist on Titan, but that it is mostly frozen. Still, under that icy exterior might lie some liquid water. After all, Earth was much colder when life began, and it happened deep in the ocean where heat and nutrients from within would leak like bubbles in a boiling pot.
Depending on how the water mixed with the methane, there is still the possibility that it could have resulted in a whole new life form from cells, the building blocks of life, unlike any we see on Earth.
Perhaps the next mission will probe a little deeper and new evidence will emerge from its liquid depths—all you’d need is an icebreaker.
Grapchic by Paloma Callo
