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Titan (moon)

Titan is Saturn’s largest moon and the second-largest moon in the Solar System.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

Titan is Saturn’s largest moon and the second-largest moon in the Solar System. It is notable for having a dense atmosphere, clouds, and stable liquids on its surface, including methane and ethane in lakes, seas, and rivers.

Discovery and naming

Titan was discovered in 1655 by Christiaan Huygens. It was the first planetary satellite discovered after the Galilean moons of Jupiter.

Physical characteristics

Titan is the second-largest moon in the Solar System and is larger than Mercury in diameter. It is an icy world with very low surface temperatures, which allow methane and ethane to exist as liquids.

Atmosphere and weather

Titan has a thick nitrogen-rich atmosphere with methane and haze. It is the only moon known to have clouds and a substantial atmosphere, and it has weather processes involving rain, rivers, lakes, and seas.

Exploration and scientific interest

Titan is of major interest because of its Earth-like surface processes and its potential for prebiotic chemistry. NASA’s Cassini mission revealed much of what is known today, and the Dragonfly mission is planned to explore the moon further.

Key facts

  • Titan is Saturn’s largest moon and the second-largest moon in the Solar System.
  • It is the only moon known to have a substantial, dense atmosphere.
  • Titan is the only place besides Earth known to have stable liquids on its surface.
  • Its surface liquids are mainly methane and ethane, forming lakes, seas, rivers, and rain.
  • Scientists think Titan may have a subsurface ocean beneath its icy crust.
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Canadian context

Titan is a major target in planetary science followed by Canadian researchers and institutions through international missions such as Cassini-Huygens, with Canadian readers often encountering Titan in astronomy education and space-science coverage.

Frequently asked questions

What is Titan?
Titan is Saturn’s largest moon and the second-largest moon in the Solar System.
Who discovered Titan?
Titan was discovered by Christiaan Huygens in 1655.
Does Titan have an atmosphere?
Yes. Titan is the only moon known to have a substantial, dense atmosphere.
Does Titan have liquid on its surface?
Yes. It is the only place besides Earth known to have stable liquids on its surface.
What are Titan’s lakes and rivers made of?
They are mainly made of liquid methane and ethane.
Why is Titan scientifically important?
Its atmosphere, surface liquids, and complex organic chemistry make it one of the most interesting places to study habitability and prebiotic chemistry.

References

  1. NASA Science — https://science.nasa.gov/saturn/moons/titan/facts/
    Supports: Titan is Saturn’s largest moon, the only moon with a substantial atmosphere, and the only place besides Earth known to have liquids on its surface.
  2. European Space Agency — https://www.esa.int/Science_Exploration/Space_Science/Cassini-Huygens/Facts_about_Titan
    Supports: Titan is Saturn’s largest moon, the second largest in the Solar System, discovered by Christiaan Huygens in 1655.
  3. Encyclopaedia Britannica — https://www.britannica.com/place/Titan-astronomy
    Supports: Titan’s discovery, dense atmosphere, and status as the only body other than Earth known to currently have liquid on its surface.
  4. NASA Science — https://science.nasa.gov/mission/cassini/science/titan/
    Supports: Titan has lakes and seas of liquid methane and ethane, hydrocarbon dunes, and evidence for a large internal ocean.