Carbon Planet - Characteristics

Characteristics

Carbon planets are predicted to be of similar diameter to silicate and water planets of the same mass, potentially making them difficult to distinguish. The equivalences of geologic features on Earth may also be present, but with different compositions. For instance, the rivers might consist of oils. If the temperature is low enough (below 350 K), then gases may be able to photochemically synthesize into long-chain hydrocarbons, which could rain down onto the surface.

NASA cancelled a mission, called TPF, which was to be an observatory much bigger than Hubble that would have been able to detect such planets. The spectra of carbon planets would lack water, but show the presence of carbonaceous substances, such as carbon monoxide.