Titan is the largest moon of Saturn. It is the second-largest natural satellite in the Solar System, after Jupiter’s moon Ganymede, and is larger than Mercury, the smallest planet in the Solar System. Titan is one of the four Galilean moons of Jupiter—the largest moons orbiting Jupiter. Discovered in 1655 by Christiaan Huygens, Titan is 50% larger than Earth’s Moon and 80% more massive. It consists mostly of ice and rocky material. Much like Venus, its atmosphere is dense and composed mostly of nitrogen.
Titan’s surface features include hydrocarbon lakes thought to be similar to those on primordial Earth that are filled with methane and ethane liquids, as well as dry riverbeds that may have been carved out by liquid methane rains long ago. With a temperature averaging around 94 K (-179 °C; -290 °F), Titan also has some similarities to cold terrestrial planets such as Mars or Pluto. Its hazy yellowish-brown atmosphere—composed mostly of nitrogen with small amounts of methane and other hydrocarbons—is much denser than Earth’s atmosphere (1.5 times as thick) despite being only 1/7th as massive because it lacks a large rocky core like our own planet does. The atmospheric pressure at Titan’s surface is about 60% higher than what we experience on Earth due to this increased density. In addition, there are indications that Titan has a subsurface ocean of water surrounded by an icy mantle similar to Europa or Ganymede (two other large moons in our Solar System).
Despite these conditions which might make it seem inhospitable to life as we know it, studies have found that certain types of bacteria could potentially survive on Titan if they were able to find food sources like hydrogen gas or organic molecules. However, there currently isn’t any direct evidence for life on this distant world—and any potential organisms would likely be very different from anything we’ve ever seen before given the unique environment found there!