There is more water in our solar system than we think.
The past decade of space exploration and the study of our own solar system has yielded one astonishing fact – our solar system does have lots of water. Scientists are discovering different forms of water on planets, their moons and comets.
Our Earth has water in all three forms – liquid as in the oceans, solid as in the polar ice caps and mountain peaks, glaciers and gaseous as in our atmosphere. Out in our solar system, many types of water are found. The most common is the 'water ice'. The other type is 'dry ice; that is actually frozen carbon dioxide. There is plenty of 'dry ice' on Mars, on its poles.
Among the planets, Mars once may have had oceans. But now, it may have underground water deposits that may be responsible for microbial growth on its surface. It has been speculated that Mars might even have seasonal ice deposits that sometimes melt on the surface.
Hot Venus contains minute quantities of water in its atmosphere too.
Comets contain lots of water in the form of 'dirty ice' that is a mixture of dust and water frozen hard. They also have frozen ammonia and methane.
Scientists are of the opinion that the many moons of Jupiter and Saturn contain water in one form or the other.
The moons of Jupiter that are suspected of having water are Europa, Ganymede and Callisto among the larger moons.
Europa's icy crust may be pointing at an ocean underneath. Scientists speculate that this ocean under the icy crust could be warm and in liquid state due to tidal effects from Jupiter. This makes Europa an attractive candidate for extra-terrestrial life.
Ganymede is even bigger than Mercury and has a 100-mile thick icy crust covering its surface. Auroreal activity on Ganymede has suggested that the ocean beneath this thick crust could be warm and salty.
Callisto, one of the larger and farther moons of Jupiter may contain water in the form of ice only.
Coming to the moons of Saturn, it was just recently discovered that Enceladus has warm and salty water.
Saturn's biggest moon, Titan, has methane in liquid form. Because of Titan's unique temperatures and pressures, methane can exist on Titan in all three forms.
The discovery of so much water in our solar system is exciting because it suggests extra-terrestrial life.