We know that water is an essential element for life as we know it on our planet. Therefore, to infer the possible existence of life on another planet or satellite in the solar system or elsewhere in the universe, we must look at the presence of water on other planets and satellites, at least to see if life as we know it here on Earth is possible.
In this article, we'll tell you everything you need to know about water on other planets and satellites and whether it could support life.
Search for water on other planets and satellites
Mercury's proximity to the sun prevents its surface from containing liquid water. Liquid water may very well have existed on the surface of Venus in the past. This is even more likely, although liquid water once existed on Mars . However, this possibility is now ruled out.
On Mars, there is evidence of water, but it is not liquid. By contrast, water on Mars exists in the form of crushed ice. It also happens on Earth, for example in the cold regions of the Arctic, a condition known as permafrost. The thin atmosphere of Mars contains trace amounts of water vapor.
But as we said, there is no conclusive evidence of liquid water on the surface of Mars. The other planets in the solar system (Jupiter, Saturn, Uranus, Neptune) are all gas giants, but some moons may contain liquid water. To learn more about the relationship between volcanoes and life in space, we recommend the following article on underwater volcanoes . You can also read about Venus's atmosphere and its impact on the search for water.
underground oceans
What Jupiter's moons Ganymede and Europa, and Saturn's moons Titan and Enceladus have in common is that they appear to have a global ocean of liquid water beneath their icy crusts. These stars in our solar system lie outside the so-called habitable zone. This zone is defined as the region around a star where the star's radiation would allow liquid water to exist on the surface of a rocky planet (or moon). But, as we've said, the liquid oceans of these rocky moons are not on their surfaces, but rather beneath layers of ice tens of kilometers thick.
The gravitational pull of the giant planets (Jupiter and Saturn) around which these moons orbit creates tidal forces. These forces are responsible for the heating necessary to keep water in these subsurface oceans liquid. Furthermore, in some cases, this energy creates internal friction which, along with the moon's own rotation on its axis, generates some volcanic activity underground. In 2005, NASA's Cassini spacecraft discovered spectacular geysers of water vapor in the southern hemisphere of Saturn's moon Enceladus. It is a small moon, only 500 kilometers in diameter. To delve deeper into the potential for life on other moons, we recommend reading about moons suitable for life . It is also interesting to investigate water on the Moon and its relationship to life.
liquid brine on mars
The conclusion of this important discovery is that in a region called Plamun Australe, located within the ice cap of the Martian south pole, under a kilometer and a half of solid water, the contours painted by radar closely resemble those of great lakes. of water and liquids found in Greenland.
In other words, there could be a large saltwater lake at least 20 kilometers long. Temperatures in the region reach -120 degrees Celsius, but below the surface, the water is liquid. This is possible because the salinity increases the pressure exerted by the ice (raising the temperature from -30 to -70 degrees Celsius), preventing the ice from freezing.
The discovery has reignited the debate about the possibility of life in this or other undiscovered Martian lakes. The Mars Express probe's radar has only detected less than 10% of Mars' south pole. There is still much to learn about the Red Planet. If you are interested in Mars and its characteristics, you can learn more in the article about interesting facts about Mars . You could also explore the topic of water on Mars in more detail.
Evidence of water on other planets and satellites
These are some of the planets and satellites where there is evidence of the existence of water:
- Europe: One of Jupiter's moons, Europa, is an intriguing candidate for harboring liquid water beneath its surface. Its ice cap is thought to conceal a subsurface global ocean, heated by tidal forces generated by the intense gravity of Jupiter and other Galilean moons.
- Enceladus and Titan: These are moons of Saturn. Enceladus has been shown to eject jets of water and steam from its surface, suggesting a subsurface ocean and geothermal activity processes. Titan has seas and lakes of liquid hydrocarbons on its surface, although liquid water is also thought to lie beneath its icy crust.
- Ceres: This is the largest body in the asteroid belt between Mars and Jupiter. Observations from the Dawn spacecraft have suggested the presence of water ice on its surface, possibly mixed with minerals and salt.
- Exoplanets: Exoplanets (planets outside our solar system) have been discovered in the "habitable zone" of their stars, where temperatures would allow liquid water to exist on the surface. Examples include the TRAPPIST-1 and Proxima Centauri b systems. However, the direct detection of water in the atmosphere of exoplanets is an ongoing technical challenge.
Water on Pluto?
Mercury is too close to the sun to have any form of water, and although we believe Venus may have had oceans hundreds of millions of years ago, water has only been detected in its atmosphere and in very small quantities. However, near the end of the solar system we find Pluto.
The dwarf planet Pluto is believed to harbor subsurface water, a theory supported by data sent back by the New Horizons probe, which conducted the most intensive study of Pluto since its flyby in 2015. The idea is that, in its early history, when temperatures reached the surface, liquid water may have existed on the planet's surface. Its formation is still relatively recent . As time passes and temperatures cool, Earth may freeze, although liquid water could still exist underground.
I hope that with this information you can learn more about the existence of water on other planets and satellites.