What are Titan's seas made of?

Liquid hydrocarbons, mainly methane and ethane with dissolved nitrogen. At about −179°C these substances, which are gases on Earth, are liquid.

Could you breathe on Titan?

No. The air is mostly nitrogen with methane and contains no oxygen to breathe. You would not need a pressure suit, since the pressure is only about 1.5 times Earth's, but you would need an oxygen supply and heavy insulation against the cold.

Is there life on Titan?

None has been found. Titan has rich organic chemistry and probably an ocean of water beneath its crust, so scientists study it to understand the chemistry that might lead to life. Dragonfly is designed to investigate this.

When will Dragonfly reach Titan?

Dragonfly is planned to launch in 2028 and arrive at Titan in 2034, then fly between sites in the equatorial dune regions and near Selk crater.

Dark seas of liquid methane under a thick orange sky, on Saturn's largest moon

Titan's methane shore

3D landscape · Titan, moon of Saturn

Land here and explore →

Titan is the second-largest moon in the Solar System, about 5,150 km across and larger than the planet Mercury. It is wrapped in a thick atmosphere of nitrogen with a little methane, denser than Earth's, and hidden beneath a smog-like orange haze. Beneath that haze lies a landscape that looks surprisingly familiar: rain, rivers, lakes, seas, dunes and shorelines, all shaped at around −179°C. In this app you can land on the shore of a methane sea near Kraken Mare and explore it in interactive 3D, under the orange haze.

On Titan, methane plays the part that water plays on Earth. It forms clouds, falls as rain, carves channels and collects in lakes and seas near the poles. Its rich organic chemistry, and a likely ocean of liquid water deep beneath its icy crust, make Titan one of the most interesting places to study how the chemistry that leads to life might begin.

Key facts

Diameter: ≈ 5,150 kmLarger than Mercury; second only to Jupiter's Ganymede among moons
Surface gravity: ≈ 1.35 m/s² (0.14 g)A little less than on our Moon
Surface temperature: ≈ −179°CVaries only a few degrees across the moon
Surface pressure: ≈ 1.5 barAbout 50% more than at sea level on Earth
Atmosphere: About 95% nitrogen, 5% methaneNear the surface; the air is about four times denser than Earth's
Orbit around Saturn: ≈ 16 daysAbout 1.2 million km from the planet
Largest sea: Kraken MareAround 400,000 km², larger than the Caspian Sea
Huygens landing: 14 January 2005The most distant landing ever made
Dragonfly: Planned launch 2028Due to arrive at Titan in 2034

A thick orange sky

Titan is the only moon in the Solar System with a substantial atmosphere. It is mostly nitrogen, like Earth's, with a few per cent of methane near the surface. The pressure at the ground is about 1.5 bar, and because the air is so cold it is about four times denser than air on Earth. Walking there would feel a little like moving through water, and the low gravity would make each step light.

High in the atmosphere, sunlight and particles from Saturn's surroundings break methane and nitrogen apart. The fragments recombine into larger organic molecules that form a thick orange haze, hiding the surface from ordinary cameras. Only with radar and at certain infrared wavelengths could the Cassini spacecraft see the ground below. At the surface, daylight would be dim and orange, perhaps a thousandth as bright as a sunny day on Earth, and Saturn would usually be hidden by the haze.

Flying with your own wings

With air about four times as dense as Earth's and gravity only about a seventh as strong, a person on Titan could in principle fly by flapping wings strapped to their arms, though they would also need a heated, sealed suit to survive.

Methane rain and rivers

Titan has a cycle of liquid much like Earth's water cycle, but with methane. Methane evaporates from lakes and the ground, forms clouds, and falls as rain. Drops would be larger than raindrops on Earth and fall slowly, drifting down like snowflakes. Over time, rain has carved branching river channels and valleys into the icy crust, which here is as hard as rock.

Rain on Titan seems to be rare in any one place but can be heavy when it comes, perhaps similar to occasional desert storms on Earth. Cassini watched clouds form and saw surfaces darken after rainfall, then brighten again as they dried. Titan's seasons each last around seven Earth years, because Saturn takes about 29 years to orbit the Sun, and the weather shifts with them.

Lakes and seas

Most of Titan's liquid sits near its north pole. The three largest bodies are called seas, or maria: Kraken Mare, the biggest at around 400,000 km²; Ligeia Mare, about the size of Lake Superior and Lake Michigan combined; and Punga Mare. Hundreds of smaller lakes, many with steep sides, are scattered around them. The south pole has fewer lakes, including Ontario Lacus.

The seas are thought to be mixtures of methane, ethane and dissolved nitrogen. Cassini's radar bounced signals off the bottom of Ligeia Mare and measured depths of around 160 metres, showing it to be very clear liquid. Kraken Mare may be deeper still. The surfaces are usually extremely calm, though Cassini detected what may have been small waves, and short-lived bright features nicknamed 'magic islands' that could be bubbles, waves or floating material.

Dunes, crust and a hidden ocean

Around Titan's equator lie huge fields of dunes, long parallel ridges up to about 100 metres high and hundreds of kilometres long. They are made not of sand but of grains of organic material that has drifted down from the haze, piled up by winds. Elsewhere there are mountains, a few impact craters and bright plains.

Titan's crust is made of water ice, frozen so hard it behaves like rock. Measurements of how Titan flexes as it orbits Saturn suggest a global ocean of liquid water, probably salty, lies beneath, perhaps 100 km or more below the surface. Whether that ocean could ever mix with the organic material at the surface is one of the major questions for future missions.

Cassini, Huygens and Dragonfly

The joint NASA, ESA and Italian Space Agency Cassini–Huygens mission reached Saturn in 2004. ESA's Huygens probe separated from Cassini and descended through Titan's atmosphere on 14 January 2005, taking about two and a half hours under parachutes and photographing river channels on the way down. It landed on a damp plain scattered with rounded pebbles of ice and sent data for about 72 minutes from the surface. It remains the most distant landing ever made.

Cassini continued to orbit Saturn until 2017, making well over a hundred close flybys of Titan and mapping its seas with radar. NASA's next mission, Dragonfly, is a car-sized rotorcraft planned to launch in 2028 and arrive in 2034. Taking advantage of the dense air and low gravity, it is planned to fly between sites in Titan's equatorial dunes and near Selk crater, studying the chemistry of the surface and searching for signs of how life's ingredients may form.

Surprising facts about Titan's methane shore

Titan is larger than the planet Mercury, though less than half as massive.
Titan is the only world other than Earth known to have rain, rivers and seas on its surface, but they are made of methane and ethane.
Its surface air pressure is about one and a half times Earth's, even though Titan is a moon.
A person could, in principle, fly on Titan by flapping wings strapped to their arms.
Titan's dunes are made of organic grains that drifted down from the sky, not of sand.
Huygens' 2005 landing on Titan remains the most distant landing ever made by a spacecraft.

Frequently asked questions

What are Titan's seas made of?: Liquid hydrocarbons, mainly methane and ethane with dissolved nitrogen. At about −179°C these substances, which are gases on Earth, are liquid.
Could you breathe on Titan?: No. The air is mostly nitrogen with methane and contains no oxygen to breathe. You would not need a pressure suit, since the pressure is only about 1.5 times Earth's, but you would need an oxygen supply and heavy insulation against the cold.
Is there life on Titan?: None has been found. Titan has rich organic chemistry and probably an ocean of water beneath its crust, so scientists study it to understand the chemistry that might lead to life. Dragonfly is designed to investigate this.
When will Dragonfly reach Titan?: Dragonfly is planned to launch in 2028 and arrive at Titan in 2034, then fly between sites in the equatorial dune regions and near Selk crater.
Can I explore Titan in the app?: Yes. You can land on the shore of a methane sea near Kraken Mare and explore it in interactive 3D, under Titan's orange haze.

Keep exploring

The landscapes in Ember’s Universe are procedural 3D scenes modelled on real places. The landforms, plants and light follow the real thing, but the details are generated, not mapped.

Sources