We don’t generally think of Saturn’s moon Titan as an Earth-like world. It has no breathable atmosphere, and with a surface temperature of about 90 Kelvin life as we know it is out of the question. But there are many parallels between Titan and Earth, and so we can see the moon as a kind of colder, smaller cousin to our own planet.
Both Earth and Titan have thick nitrogen atmospheres. Earth’s also has about 20% oxygen, but the atmospheric dynamics are similar. On Titan, methane plays a similar role to water on Earth. Titan has clouds, rain and large lakes or seas. It has seasons following the changing tilt of its orbital plane relative to the Sun. As a result, the terrain of Titan is interestingly similar to Earths, with rivers, flood plains, and mountains. It even has ice volcanoes, and so is geologically active.
Because of its lower temperature, and the way methane obscures visible light, we have to look in the infrared to see much of these details. A recent image by the Cassini mission does just that. Shown above, the false-color image gives infrared wavelengths more Earth-like hues. The result is Titan as an Earth-like world. It’s a great example of how sometimes a world so different from our own can also be hauntingly similar.