Many people are accustomed to believe that the Earth is the only planet in the solar system that has colossal water reserves. However, compared to some other places in the solar system, our homeworld is a veritable desert, both in terms of the total volume of water and the amount of liquid on Earth relative to the size of the planet.
Take, for example, Jupiter's icy moon Europa, which is smaller in size than our Moon. More recently, scientists analyzed 20-year-old data from one of the Voyager space probes and found even more evidence that Europe's water reserves are twice that of our home planet. There are serious suspicions that even tiny Pluto has a subsurface ocean comparable in volume to our Earth's.
Steve Vance, a planetary scientist at NASA's Jet Propulsion Laboratory, has been researching worlds that may hide water under their surface for many years. He deduced the average values of the thickness of the ice crusts of the surface of the worlds of the solar system and the depth of their oceans, and also calculated how much water there may be on these objects.
The infographic below reflects the data obtained by Vance, as well as information from other sources, showing the likely volume of liquid water from nine known "water worlds", including our Earth.
The amount of water on the graph is expressed in zettaliters, a unit equal to 1,000,000,000,000,000,000,000 liters, or 1 billion cubic kilometers.
According to the National Oceanic and Atmospheric Administration, Earth has only about 1.3335 zettaliters.
Based on the volume of water that the worlds of the solar system have (from a smaller reserve to a larger one), the list looks like this: Enceladus (satellite of Saturn), Triton (satellite of Neptune), Dione (satellite of Saturn), Pluto (dwarf planet), Earth, Europa (moon of Jupiter), Callisto (moon of Jupiter), Titan (moon of Saturn) and Ganymede (moon of Jupiter).
Promotional video:
Ganymede is the largest satellite of the gas giant Jupiter and the most "watery" world in the solar system for another reason: 69 percent of the total volume of the satellite can be liquid water, which is significantly more than any other cosmic body from the list above.
According to scientists, Mimas, the moon of Saturn, as well as Ceres, the largest asteroid in the solar system, can also have oceans of water. However, researchers aren't sure how big these oceans might be. In order to surely confirm or deny this opinion, it will be necessary to conduct more than one space mission.
NASA is currently planning a Europa Clipper mission to Europe. Within its framework, scientists want to draw up a very accurate map of the ice satellite. Researchers expect the mission to begin sometime between 2022 and 2025.
Scientists believe that the probe will be able to make more accurate calculations of the size of Europa's ocean, as well as "taste and smell" the particles of water geysers escaping from the satellite's surface.
The European Space Agency is planning a similar mission called Jupiter Icy Moons Explorer. Its launch should take place in 2022. The spacecraft will have to reach Jupiter in 2030.
Within the framework of this mission, it is planned to conduct two overflights of Europe. The spacecraft will then orbit around Ganymede for 8 months, collecting scientific data and sending it back to Earth.
Who knows, perhaps one of these probes will find the first irrefutable evidence of the existence of life hundreds of millions of kilometers from Earth.
Nikolay Khizhnyak