Titan

Titan, with Surface Details Revealed

Titan, also known as Saturn I, is the largest natural satellite of the outer planet, Saturn, and the second largest moon in the Solar System, just behind Ganymede, one of the Galilean moons belonging to the outer planet, Jupiter. This however is the only moon known in the Solar System to have a dense atmosphere and is even believed to have surface water, the only other body to have received this classification after our own Earth. Titan was discovered on March 25, 1655 by the Dutch astronomer Christiaan Huygens.

## Surface

The surface of Titan can only be seen through high-tech radar telescopes, for it is completely covered by a dense, orange atmosphere. The surface of Titan is in many ways similar to Earth's, and in some places even Earth's moon. There have been reported sand dunes on Titan's surface, which are very similar to the likes of those seen on Earth - the lining of sand is, in comparison, similar to those of the Namib Desert. The Shangri-la of Titan, a long and extremely dark surface feature (referred to as a *dark albedo feature*), can be compared to the mares of Earth's moon. There are many faculae on the surface of Titan including the Shikoku Facula and the Sotra Facula.

## Atmosphere

The atmosphere of Titan is the only fully developed atmosphere of any moon in the Solar System, and is also the densest of any moon. The atmosphere's presence was first discovered by Spanish astronomer Josep Comas Solà in 1903. The atmosphere is composed of 98.4% nitrogen, which makes it ~1.2 times more massive than Earth's atmosphere. The rest of the atmosphere is composed of trace gases including ethane, propane, carbon dioxide, and argon.

## Composition

The composition of Titan makes it more massive than any other moon belonging to Saturn (aka the *Saturnian moons*). The uppermost layer is the crust which is mostly covered in water-ice. There's an ocean located just beneath the ice. Oceans and lakes are found on the crust. Titan is so cold that the gas changes state and becomes a liquid. Under the crust is the upper mantal. It's unknown what is under the upper mantal. At the south pole of Titan is a permanent hurricane that continues to expand today. It pushes matter into the atmosphere, making itself denser as it expands. Since clouds typically cover about 0.9% of Titan's surface, this hurricane is unique, for it covers quite a distance. Titan might have life, or it might not - but it does have rivers and rocks.

## Structure

Titan’s internal structure isn’t entirely known, but one model based on data from the Cassini-Huygens mission suggests Titan has five primary layers. The innermost layer is a core of rock (specifically, water-bearing silicate rock) about 2,500 miles (4,000 kilometers) in diameter. Surrounding the core is a shell of water ice—a special type called ice-VI that is only found at extremely high-pressures. The high-pressure ice is surrounded by a layer of salty liquid water, on top of which sits an outer crust of water ice. This surface is coated with organic molecules that have rained or otherwise settled out of the atmosphere in the form of sands and liquids. The surface is hugged by a dense atmosphere.