A Jarful of Titan Could Teach Us A Lot About Life There, and Here On Earth

Titan is a distant, exotic, and dangerous world. It’s frigid temperatures and hydrocarbon chemistry is like nothing else in the Solar System. Now that NASA is heading there, some researchers are getting a jump on the mission by recreating Titan’s chemistry in jars.

In June NASA announced their Dragonfly mission to Titan. Dragonfly is a quad-copter (or octocopter, depending on how you look at it) that will be launched in 2026 and will arrive at Saturn’s largest moon in 2034. Dragonfly’s overall objective is to search for the building blocks of life. Titan is seen as an analog to the very early Earth, largely because it has a thick atmosphere and liquids flowing on the surface. Titan may also have a subsurface ocean. Scientists think that studying the chemistry there may shed light on the appearance of life on Earth.

To see what they could learn about any possible life on Saturn’s frigid moon, researchers at the Southern Methodist University wanted to recreate the chemical, atmospheric, and surface properties of Titan to see if they could lead to life. The project will be led by SMU assistant professor of chemistry Tom Runcevski. It’s funded by the Welch Foundation, a private organization that funds basic chemical research.

In this illustration, the Dragonfly helicopter drone is descending to the surface of Titan. Image: NASA
In this illustration, the Dragonfly helicopter drone is descending to the surface of Titan. Image: NASA

The study consists of multiple cylinders the size of a needle top. In them, they’ll take what we learned from the Huygens lander to recreate conditions on Titan. The idea is to see what kinds of structures form in the jars.

“Titan is a hostile place, with lakes and seas of liquid methane, and rains and storms of methane. The storms carry organic molecules produced in the atmosphere to the surface, and at the surface conditions, only methane, ethane and propane are liquids. All other organic molecules are in their solid form – or, as we would call them on Earth, minerals,” Runcevski explained.

“We are interested in the chemical composition and crystal structure of these organic minerals, because it is believed that minerals played a key role in the origins of life on Earth,” he said. “Hence, our research may help assess these possibilities for strange “methanogenic” Titanean life.”

The first-ever images of the surface of a new moon or planet are always exciting. The Huygens probe was launched from Cassini to the surface of Titan, but was not able investigate the lakes and seas on the surface. Image Credit: ESA/NASA/JPL/University of Arizona
The first-ever images of the surface of Titan, taken by the Huygens probe. Image Credit: ESA/NASA/JPL/University of Arizona

According to Runcevski, it all starts with water.

“We can recreate this world step by step in a cylinder made of glass,” he said. “First, we will introduce water, which freezes into ice. Second, we will top that layer of ice with ethane that liquidizes as a ‘lake.’ Then we will fill the remaining cylinder with nitrogen.”

That forms the basis of the experiment, but after that is where it might get interesting.

They plan to introduce different molecules into the jars to mimic the hydrocarbon rainfall on Titan. Then they will raise the temperature to the point that the lakes dry and the jar resembles Titan’s surface, then introduce the hydrocarbon rainfall and the different molecules that come with it. Then they can examine the jars to see what types of structures formed. By varying the conditions slightly they can perform multiple experiments.

Titan is weird because its surface is made of organic structures. There’s nowhere on Earth that these types of experiments can be performed outside of a laboratory. The scientists are hoping that whatever they learn can help Dragonfly prepare for its epic journey to the frigid moon.

The view of Titan from the descending Huygens spacecraft on January 14, 2005. Credit: ESA/NASA/JPL/University of Arizona.

There’s been a lot of speculation about potential life on Titan. Even though it’s frigid, at about 94 K (-179.2 °C; -290.5 °F), it’s still an intriguing place from an astrobiological perspective. That’s largely because of the liquids that flow on its surface.

As far as we know from our place here on Earth, life needs water to exist. That’s because the smallest unit of life, the cell, needs water to perform its functions. But we don’t know if it’s possible for another type of life to exist, one that uses methane or ethane as its liquid, rather than water. Some scientists find the idea worth investigating; some poo-poo the whole idea.

But the middle position taken by many scientists says that whether or not a type of hydrocarbon life exists or not, Titan is a great place to study the early Earth.

A team of scientists at Cornell University created a hypothetical cell membrane that could exist on Titan. Image Credit: Credit:?James?Stevenson

That’s largely why the Dragonfly mission was born.

Nobody is convinced that we’ll find life on Titan’s surface, or in its subsurface ocean, or in the jarfuls of Titan-like conditions being created in labs. But we may find important clues that help us understand how we came to be. We may also learn something about all of the exoplanets we’ll be studying in greater detail in the coming years, and whether or not they may harbor life.