Mysterious 'bathtub rings' around Titan's lakes could be made of 'alien crystals,' study says

Saturn's moon Titan has fascinated scientists as it contains lakes that have similar features to those on Earth and is the only other celestial object in the solar system to have surface liquid. In areas of the moon where the liquid has evaporated, dark smears have been spotted, which researchers believe operate in similar fashion to “bathtub rings” — and they might be made of "alien crystals."