Scientists Believe There’s Life on Titan, And It’s Weirder Than You Think

For years, Mars has captivated our imagination as a possible second home. Yet, as we delve deeper into our solar system, new contenders for colonization emerge, some potentially even more suitable. The early stages of life on Earth were vastly different from today. The atmosphere differed, alien species thrived, and the landscapes were unrecognizable compared to now. So, as we search for habitable celestial bodies, it’s worth broadening our criteria to consider conditions conducive to alien life forms. In our solar system, one such candidate stands out: Titan. How does Titan mirror the primordial Earth? What are the enigmatic deserts on Saturn’s largest moon, and what triggers the eruptions in its lakes? Titan [Diameter: 3,200 miles / 5,150 km], the largest of Saturn’s 146 moons, is even bigger than Mercury. But it’s no o rdinary satellite. The gigantic moon is so similar to Earth, it’s almost hard to believe. Not only does Titan have lakes, seas, and rivers, but it also hides a subsurface ocean of water, 50 miles [80 km] below the icy ground. In the moon’s skies, there are clouds, on its surface – organics. It rains on Titan, liquid bodies replenish lakes and seas, and then evaporate, launching an Earth-like hydrological cycle. The atmosphere of nitrogen and methane that envelops the satellite is t hick enough for you to safely stroll around its surface without a pressure suit. But that’s only if Titan wasn’t as cold as -290°F / -179°C and had an oxygen-nitrogen atmosphere like the Earth. And if you had wings attached to your suit, you could even fly as the moon’s gravity is just 14% of the Earth’s. Because of this, you would also witness rain falling in slow-motion, about 6 times slower compared to Earth. Although it would be no ordinary rain. On Titan, it rains liquid me thane, and its droplets are roughly 50% larger than raindrops we see on our planet. Titan is located some 750 million miles [1,200,000,000 km] from Earth, where it revolves around Saturn in about 16 days. Titan is tidally locked to the sixth planet. But even though one of its sides is always facing Saturn, the satellite still has intricate weather patterns. Saturn’s largest moon receives 100 times less solar energy than our planet, and it has a thick atmosphere extending 10 times hig her into space. In these conditions, not much light can get through and reach the surface. For the first half of Titan’s day, which is equivalent to 16 Earth days, its surface is bathed in a faint orange haze. Looking through this haze would be like trying to see beyond thick fire smoke. The skies during this part of the day could be 100-1000 times dimmer than here on our planet in an afternoon. And the other part of the day brings total darkness to the surface. But even if it wa s bright enough, you still wouldn’t see Saturn from the surface of Titan because of the haze. Interestingly, daytime isn’t the brightest part of the moon’s day. According to computer simulations, the brightest it gets on this mysterious world is during twilight – up to a factor of 200 compared to daytime. This is something that happens because of the way light is scattered by the haze particles in the atmosphere. And since Titan is tidally locked, with a permanent daylit side and n ightside, there’s also a permanent twilight zone – a border in between the two sides called terminator. Titan, like Earth, experiences eclipses, which can last up to 6 hours. This is like having a second night in the middle of a day. Of course, you would only notice it if you were on the side of the Titan facing Saturn. Otherwise, a solar eclipse would happen during nighttime. Understanding this is important as it tells scientists how much light Titan’s atmosphere and its surface r eceives from the Sun, which dictates what conditions a potential life on Titan would have to live in. Just recently, the James Webb Space Telescope was able to detect clouds that form in Titan’s lower atmosphere during late summertime when its surface absorbs more heat. And this means that the moon has seasonal weather patterns, just like scientists have predicted it. Titan’s tilt relative to the Sun closely resembles that of Saturn, so both celestial bodies experience seasons of ap proximately equal duration, changing about every 7 Earth years. Although at a slow rate, seasonal shifts bring change in weather on Titan. When the Earth’s axis is tilted neither away nor toward the Sun, something interesting happens. Imagine a line that cuts through the north and south poles, dividing the planet in half. During this time, occurring twice a year, night and day have about the same length all over the world. This phenomenon is called the equinox, and Titan experiences it too, although less frequently – about every 15 years. But when this time of the moon’s year comes, enormous clouds of methane form in its equatorial regions, bringing about severe wind storms. During summer on Titan, the winds blow stronger. During the Cassini mission, scientists saw waves on Titan’s lakes, and they were unlike any waves here on Earth. Titan’s weak gravity allows these waves to be much bigger, about seven times taller than waves in the Earth’s oceans. But they m ove more slowly, up to three times slower. Winds on Titan also fuel powerful dust storms. Something like this happens in arid areas on Earth too, when big dust clouds form right before storms. The only other place in the solar system this phenomenon has been detected is Mars. This is how organics in the form of dust are scattered around on Titan’s surface. And although downpours are a rare phenomenon on Saturn’s largest moon, when they do happen, they leave behind a fascinating foo tprint. Titan’s rains are heavy and have a big impact on the surface. They create something called “alluvial fans.” These features are a bit like piles of dirt and rocks shaped like triangles. They form when water or ice flows and leaves behind the stuff it was carrying. Scientists have also detected dune fields on Titan taking up to 13% of the moon’s surface. Compared to sand dunes found on Earth, they are enormous in size – hundreds of miles long, 1.2 miles [2 km] wide, and 330 fe et [100 m] high. There’s more sand on Titan than anywhere else we know of, although this sand isn’t made of silicates like it is on our planet. Instead, it consists of solid hydrocarbons that fall like rain from the atmosphere. On Earth, we understand how landforms are created through a straightforward process: rocks break down into tiny grains, wind carries these grains to specific areas, they pile up, and eventually, they shape the land. But on Saturn’s largest moon, things are more puzzling. The origin of its landforms has been a mystery because the sand grains on Titan are quite different from those on Earth. They’re weaker and thought to be more temporary. However, despite this, we’ve observed long-lasting sand dunes on Titan. When the wind transports sand grains, they should collide with each other and the surface, which usually makes them smaller over time. So how do these grains manage to stick around long enough to form significant landforms? Afte r studying Titan’s landscape, scientists discovered something fascinating. It turns out that the moon has a special type of sedimentary process known as “sintering”, where neighboring grains smash together and fuse into larger, If sand on Titan can adapt in such a way to form complex landforms, could life have adapted similarly? There are a lot of similarities between our home planet and this alien faraway world. The problem with Titan is, its ingredients seem to be all wrong. What’s water on Earth, is liquid methane and ethane there, including its clouds, rivers, lakes, and seas. But one thing is certain – this celestial body is still active. Even liquids flowing on the surface of Titan involve complex physical processes. Similar to water bodies on our planet, methane lakes on Titan can stratify, that is, create layers depending on density difference. And not only that, but the liquefied met hane and ethane lakes could potentially erupt. This happens due to the combination of methane, ethane, and nitrogen, resulting in bubbles powerful enough to shape river deltas within the moon’s liquid bodies. Understanding how bubbles form in Titan’s lakes helps scientists explore how liquids behave on this intriguing moon. Imagine if a submarine were sent to explore Titan’s lakes one day. If it gives off heat, it could actually cause an explosion of bubbles, just like the ones sc ientists have discovered. So, these findings not only tell us about Titan but also hint at some surprising challenges a future spacecraft might encounter in those alien waters. Whatever life forms could potentially exist there, they would have a completely different biology, and so they would look and act like nothing we’ve ever seen before. According to a team of researchers from Cornell University, it is possible for cell membranes to form in the conditions present on Titan right n ow. On Earth, cell membranes are made up of special molecules called phospholipids. Imagine these molecules as having a head and a tail. The head is a bit like a magnet, with a positive and negative side. The tail is neutral, meaning it has no magnetic quality. Imagine these molecules in water like a sandwich with two slices of bread. The heads of the molecules are like the outer sides of the bread, and they really like the water, so they face outward. But the tails of the molecule s are like the inside of the bread, and they want to stay away from the water, so they hide in the middle. This arrangement makes the membrane flexible – something that is crucial for life. If there’s any form of life on Titan, it would probably need to have a similar membrane. The problem is, methane has an even distribution of electrical charges, so Titan doesn’t have the right conditions to make these Earth-like membranes. Because of this,   life on Titan would have to find a  di fferent way to build its “cell walls.” But scientists have been able to create  inside-out membranes in such non-polar   liquids in a laboratory. And they believe  that Titanian cell membranes would have a   similar structure. Although they would have  to be composed of something else, as liquids   on Saturn’s largest moon probably lack phosphorus  and oxygen, and are too frigid for phospholipids. So what kind of a molecule could this be? Although the Titanian atmosphere is mostly made of  metha ne and nitrogen, it has traces of different   compounds as well. Computer models have shown that  a substance called “acrylonitrile” would be able   to form cell membranes in non-polar liquid methane  on Titan. The Cassini mission has previously   detected small amounts of acrylonitrile in the  moon’s atmosphere, about 10 parts per million. Even though there’s a vast difference in  temperature in which Earth-like membranes   form and Titanian membranes could form, they  both share surprisingly s imilar qualities,   like stability and internal resistance  to external force. So it’s possible for   membranes to form in frigid temperatures  of Titan’s lakes, and survive there. The possibility of methane-based life would change  our entire outlook. Instead of focusing solely on   planets in the “habitable zone” of stars, where  conditions are Earth-like, we’d also explore   worlds farther from their stars where methane  can exist as a liquid. Within our galaxy alone,   the number of potentia l places to find alien life  forms would skyrocket. And if life, on some of   these worlds, has persisted for long enough to  develop into complex organisms, we might find   a living counterpart of an imaginary creature,  like those mentioned in fantasy movies and books. But even if, at this stage of Titan’s history,  life cannot survive on its surface, there’s a   subsurface ocean of liquid water hiding beneath  the moon’s icy coating. Scientists are trying to   find out if organics can penetra te through this  ice shell into the ocean. If this is something   that happens on Titan, then this subsurface water  could be potentially habitable. Although we still   don’t know much, like what the density or  the composition of this global ocean is,   its temperature, and how it interacts with the  icy crust above. Another big question is whether   there’s a source of chemical energy down there  to allow for metabolism. But one bacterium with   a rare metabolism that’s been found on Earth cou ld  potentially live in the Titan’s subsurface ocean. Billions of years ago, the Earth had  a very different atmosphere with high   amounts of nitrogen, CO2, and water  vapor, which descended to the surface,   launching a life cycle. The building blocks of  life on our planet may have once been the same   ingredients we see today on Titan. In a way,  Saturn’s largest satellite is a real-life lab   where astrobiologists can study how these  ingredients might have played a role in   the beginnings tential habitability,   and whether the ingredients for life might  indeed be present in this distant world. If we discover signs of alien life on  Titan, what might these otherworldly   creatures look like