Liquid water, possible non-Earth life and manned mission or colonization targets in our solar system

Oceans trapped under ice appear to be pretty common in the solar system and one of them, on a small moon of Saturn’s, appears to be quite hot. Scientists reported evidence for hydrothermal vents on the Saturnian moon Enceladus, with temperatures of its rocky core surpassing 194 degrees Fahrenheit (90 degrees Celsius) in spots. The discovery, if confirmed, would make Enceladus the only place other than Earth where such chemical reactions between rock and heated water are known to be occurring today — and for many scientists, it would make Enceladus a most promising place to look for life.

Any place with liquid water is a candidate for microbial extraterrestrial life. Mars, Titan, Europa, Ceres, Enceladus, and Ganymede have the presence of water ice and speculation that life may exists there. There are now six candidate locations for liquid water in solar system other than Earth.

The Journal of Geophysical Research: Space Physics, another team reported signs of another under-ice ocean, on Ganymede, the largest of Jupiter’s moons. Scientists are already convinced that there is a large ocean, also covered by ice, on another Jovian moon, Europa. NASA’s Galileo spacecraft had also found hints of hidden water on Ganymede and on another of Jupiter’s moons, Callisto.

Journal of Geophysical Review – The search for a subsurface ocean in Ganymede with Hubble Space Telescope observations of its auroral ovals

Europa is estimated to have twice the amount of water as Earth.

Scientists have long suspected that there was an ocean of liquid water on Ganymede — the largest moon in the solar system, at about 3,273 miles (5,268 kilometers) across — has an ocean of liquid water beneath its surface. The Galileo probe measured Ganymede’s magnetic field in 2002, providing some data supporting the theory that the moon has an ocean. It is estimated that Ganymede has more water than Earth.

Liquid water moons of gas giants and in asteroid belts could be common outside our solar system as well. The most common of the thousands of exoplanets that have been identified are gas giants.

Enceladus could have a 10 kilometer thick liquid water Ocean under 30-40 kilometers of ice.

Enceladus

Water appears to make up about 40 percent of Ceres’ volume.

Saturn’s moon Titan

Europa

Water on Mars exists today almost exclusively as ice, with a small amount present in the atmosphere as vapour. The only place where water ice is visible at the surface is at the north polar ice cap.[2] Abundant water ice is also present beneath the permanent carbon dioxide ice cap at the Martian south pole and in the shallow subsurface at more temperate latitudes. More than five million cubic kilometers of ice have been identified at or near the surface of modern Mars, enough to cover the whole planet to a depth of 35 meters. Even more ice is likely to be locked away in the deep subsurface.

Some liquid water may occur transiently on the Martian surface today but only under certain conditions.

Abstract – on Ganymede water

We present a new approach to search for a subsurface ocean within Ganymede through observations and modeling of the dynamics of its auroral ovals. The locations of the auroral ovals oscillate due to Jupiter’s time-varying magnetospheric field seen in the rest frame of Ganymede. If an electrically conductive ocean is present, the external time-varying magnetic field is reduced due to induction within the ocean and the oscillation amplitude of the ovals decreases. Hubble Space Telescope (HST) observations show that the locations of the ovals oscillate on average by 2.0° ±1.3°. Our model calculations predict a significantly stronger oscillation by 5.8° ± 1.3° without ocean compared to 2.2°±1.3° if an ocean is present. Because the ocean and the no-ocean hypotheses cannot be separated by simple visual inspection of individual HST images, we apply a statistical analysis including a Monte Carlo test to also address the uncertainty caused by the patchiness of observed emissions. The observations require a minimum electrical conductivity of 0.09 S/m for an ocean assumed to be located between 150 km and 250 km depth or alternatively a maximum depth of the top of the ocean at 330 km. Our analysis implies that Ganymede’s dynamo possesses an outstandingly low quadrupole-to-dipole moment ratio. The new technique applied here is suited to probe the interior of other planetary bodies by monitoring their auroral response to time-varying magnetic fields.

SOURCES- Wikipedia, Nasa, Journal of Geophysical Review , Nature

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