Extraterrestrial liquid water extrasolar planetary systems appear to have very different compositions to the Solar System, though there is probably sample bias arising from the detection methods. Liquid water has a distinct absorption spectroscopy signature compared to other states of water due to the state of its hydrogen bonds. Despite the confirmation of extraterrestrial water vapor and ice, however, the spectral signature of liquid water is yet to be confirmed outside of Earth. The signatures of surface water on terrestrial planets may be undetectable through thick atmospheres across the vast distances of space using current technology. Seasonal flows on warm Martian slopes, though
Fictional planets of the Solar System Fictional planets of the Solar System The fictional portrayal of our Solar System has often included planets, moons, and other celestial objects which do not actually exist in reality. Some of these objects were, at one time, seriously considered as hypothetical planets which were either thought to have been observed, or were hypothesized in order to explain certain celestial phenomena. Often such objects continued to be used in literature long after the hypotheses upon which they were based had been abandoned. Other non-existent Solar System objects used in fiction have been proposed or hypothesized by persons with no scientific standing,