Water is life. At least as we know it. Every living organism on Earth uses liquid water, and researchers studying the origin of life have found that the complex chemistry of life probably exists in water. A hot pool on the Earth’s surface Near a deep sea vent
That’s why planetary scientists are particularly interested in places outside Earth where liquid water exists.
meanwhile Earth
Let’s take a closer look at some of the most promising water worlds in our solar system and beyond.
Europe
Jupiter’s moon Europa photographed by the JunoCam aboard NASA’s Juno spacecraft as it flew close to Jupiter on September 29, 2022. (Image credits: Image data: NASA/JPL-Caltech/SwRI/MSSS. Image processing: Björn Jónsson (CC BY 3.0))
Scientists have discovered that Jupiter’s moons Europe National Aeronautics and Space Administration (NASA) The Galileo project was launched in 1989. For nearly eight years, Galileo spacecraft Jupiter
of Europa Clipper Determine if it is habitable
Callisto
Callisto photographed by NASA’s Galileo spacecraft. (Image courtesy of NASA/JPL/DLR)
Callisto There is a liquid ocean underground
Ganymede
NASA’s Juno spacecraft captured this image as it passed by Ganymede on June 7, 2021. (Image courtesy: NASA/JPL-Caltech/SwRI/MSSS)
In 2015, scientists Hubble Space Telescope Ganymede Had an ocean of liquid water inside Aurora
Ganymede’s oceans are thought to be 60 miles (100 km) thick, nearly 10 times deeper than Earth’s oceans. Galileo satellites Solar System
Enceladus
Infrared Earth map of Enceladus. (Images courtesy of NASA/JPL-Caltech/University of Arizona/LPG/CNRS/University of Nantes/Institut des Sciences Aéros)
Enceladus Saturn
This water and ice erupts from an inland sea, and in 2005 Cassini spacecraft discovered
Giant
Titan as seen through the eyes of the Cassini spacecraft. (Images courtesy of NASA/JPL-Caltech/University of Nantes/University of Arizona)
Saturn’s largest moon, Giant
Although Titan’s chemical composition is very different from Earth, the large moon has characteristics associated with habitability, including a thick atmosphere and dynamic geological and weathering processes.
TOI-1452b
An artist’s impression of TOI-1452b orbiting one of the red dwarf stars in the binary system. (Image credit: Benoit Gougeon, University of Montreal)
In 2022, NASA Transiting exoplanet exploration satellite Discovery of exoplanet TOI-1452 b Size of the Earth
TOI-1452 b is located about 100 light years away from Earth. James Webb Space Telescope
LHS-1140b
Artist’s impression of super-Earth LHS-1140 b. (Image source: ESO/spaceengine.org)
In July 2024, researchers using JWST will The atmosphere of exoplanet LHS-1140 b Sun Light years
Additionally, JWST data suggests that the planet may be made up of 10 to 20 percent liquid water. LHS-1140 b orbits in such a way that the same side always faces the star. What’s more, current models suggest that the planet may be a giant snowball, meaning there may be a “bull’s-eye” ocean on the side that always faces the star.
Kepler 138 c and d
An artistic impression of the Kepler-138 planetary system. In this illustration, the super-Earth Kepler-138 d is in the foreground, with planet Kepler-138 c on the left and planet Kepler-138 b in silhouette in the background as it transits the central star. (Images by NASA, ESA, and Leah Hustak (STScI))
Two possible water planets, Kepler-138 c and Kepler-138 d, are Red dwarf May have high moisture content
Researchers believe that up to half of the materials that make up these planets should be lighter than rock but heavier than hydrogen or helium — the most common element in the universe that fits this criteria is water.
HAT-P-11b Hat
Artist’s impression of HAT-P-11 b passing in front of its home star. (Image source: NASA, ESA, R. Hurt (JPL-Caltech))
In 2014, astronomers Water vapor discovered on Neptune-sized planet Exoplanets
The researchers found water in HAT-P-11 b’s atmosphere using a method called transmission spectroscopy. When an exoplanet passes by its host star (from our perspective), the star’s light travels through the exoplanet’s atmosphere. Various particles in the atmosphere absorb some of the star’s light at specific wavelengths. By analyzing which wavelengths are absorbed, scientists can determine the chemical composition of the atmosphere.
K2-18b
K2-18 b has been shown to contain water and may have a warm environment capable of supporting life. (Images courtesy of ESA/Hubble, M. Kornmesser)
In 2019, water vapor Found in the atmosphere The discovery of a super-Earth planet called K2-18 b, 110 light years away from our solar system, orbits a red dwarf star, at just the right distance for liquid water to exist on its surface.
But planetary scientists aren’t sure whether the planet is a rocky world or a giant ball of liquid and gas.
Additional Information Based on current exoplanet data, Super-Earths and Sub-Neptunians are thought to be the most common planet classes in the galaxy, and some of these planets are likely water worlds. However, these planets are large, and the interaction of the water in their oceans with the rocky interior will determine how habitable these planets will be. More details on these dynamics are published in this study. Journal Nature
Europa Clipper will provide scientists with unprecedented information about the habitability of small water planets, like those found around Jupiter and Saturn. Why the mission will visit Europa
Water planets are thought to be widespread in the universe, and may be one of the best places to search for extraterrestrial life. For a discussion of how common water planets are, see Journal of Science .
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