ESA (European Space Agency) made the Huygens probe, named after the Dutch astronomer, mathematician, and physicist Christiaan Huygens who discovered Titan. On December 25 2004, the Huygens probe left the orbiter. A couple weeks later, the probe parachuted onto Saturn's largest moon Titan. Astronomers have wondered what the surface of Titan was like, since it was hidden under thick clouds. It is the only moon in our solar system with a thick atmosphere. The probe descended and sent pictures and other data back for scientists to study. After 90 minutes on the moon, the spacecraft stopped working, as expected. It is the farthest place we have ever landed a spacecraft. The pictures sent while parachuting showed rivers, probably of liquid methane. The surface is much too cold for water.