Which World In Our Solar System Has The Most Water?

May 29, 2019

When asked which Solar system world has the most water most people would say the earth has the most water. Although 70% of the earth’s surface is covered by water only 0.12% of Earth’s total volume is liquid water.

Earth - "The Water Planet"
Credit NASA

Steve Vance, a NASA planetary scientist has kept a data base of research on ocean worlds in our solar system. He has ranked the worlds by how much liquid water they have.  Ranking from least to most, the list includes:

Enceladus, Triton, Dione, Pluto, Earth, with Europa, Callisto, Titan and Ganymede have the most liquid water by volume.

Jupiter’s moon Ganymede has 46%, and Europa has 16% liquid water by volume. Two unmanned space missions are planned to investigate the ocean of Europa.  NASA will send the Europa Clipper to Europa while the European Space Agency will send the Jupiter Icy Moons Explorer to Europa and Ganymede.  Both missions are planned to get to Jupiter in the early 2030’s. 

Life as we know it depends of water.  It is possible that these missions might find signs of life.  

Look for the Jupiter and its moons rising in the east after sunset by the end of May.