O ne of the main quests of scientists is to find water on another planet. This and other factors would make it possible to support life as we know it elsewhere in our solar system. Scientists assumed because of the harsh and unfavorable conditions on Mercury that water could not exist. With the atmosphere being so thin and the temperatures being so extreme it would seem highly improbable. Recently, in 1991 scientists at Caltech bounced radio waves off the surface of Mercury and discovered a puzzling bright return toward the north pole. This could only be explained by the presence of ice near the surface of the north pole. Is it possible for ice to exist on Mercury? Well, since Mercury's rotation is almost perpendicular to its orbital plain the interior of any craters located in its northern most region would never be exposed to sunlight. This would theoretically cause the craters' internal temperature to be less than -160 degrees Celsius. In these craters ice could be produced and frozen from processes within the planet itself or possibly ice that was located on a comet that collided with Mercury. This ice could be covered up by a thin layer of dust and debris and still give scientists these readings.