What if the vacuum of our solar system,and the inferred of the Sun has
split the bond over time of the water molecule? That means in this
spacetime comets that were dirty "snow" balls,and now are rather dry.
Close up pictures of Temple 1 showed to us gives reality to this idea.
All things evolve in time,and that is especially true with water
immersed in a vacuum,and no protection from the Sun's rays. Our
Moon,and Mars can be easily added to this thinking. Bert