Not too long ago, scientists on the hunt for habitable worlds and extraterrestrial life would have said that the best bet is to look for where there is water. However, they now understand that this sole condition really doesn't do much to narrow things down, as the Universe may very well be awash with the stuff.
That's at least according to NASA, who recently released an intriguing overview of all the watery worlds that have so far been discovered in our own solar system alone.
"NASA science activities have provided a wave of amazing findings related to water in recent years that inspire us to continue investigating our origins and the fascinating possibilities for other worlds, and life, in the Universe," Ellen Stofan, chief scientist for the agency, said in a recent statement.
The overview describes how water's elements, hydrogen and oxygen, are "some of the most abundant elements in the Universe," with the signature of water vapor even seen in giant clouds and disks of stardust. It likewise can be found slipping from the surface of comets, where that frozen heavenly body's melting nucleolus lets off a wrapping coma and streaking tail of re-frozen ice particles.
It has even been proposed that it was a comet or massive wet asteroids that delivered water to Earth, but recent findings from the European Space Agency's (ESA) historic Rosetta mission have revealed how water signatures from comet 67P/Churyumov-Gerasimenko are nothing like those found on our own watery world. (Scroll to read on...)
But what about other worlds? NASA highlights how there are nine extraterrestrial bodies within our very own solar system alone that are expected to play host to ice, vapor, ground water, and even vast oceans 10 times deeper than Earth's.
You can check out an incredible info -graphic of all these recent discoveries, as provided by experts at NASA Jet Propulsion Laboratory, here.
"NASA spacecraft have also found signs of water in permanently shadowed craters on Mercury and our Moon, which hold a record of icy impacts across the ages like cryogenic keepsakes," the space agency reported.
And yet, while this seems like there's a lot more water in our solar system alone than once thought, new investigations are revealing more and more compelling evidence that what we see today is but a fraction of what once was. Modern-day Mars, for instance, likely boasts a mere 13 percent of the water it once had - now locked up in vast swaths of ice at its poles. However, prior to losing the great majority of its atmospheric protections for mysterious reasons, the Red Planet may have had a deep body of water 450 feet deep and larger than Earth's vast Arctic Ocean. (Scroll to read on...)
The amount of water (likely as vapor) hiding among the thick clouds of Jupiter may also be a critical piece missing in the puzzle that is water. Experts hope to understand how it spread even in the hottest and driest times of our solar system's formation, and looking to places like Ceres - a young planet which had its formation halted by Jupiter's influence - and the gas giant itself to reveal this secret.
"Jupiter was likely the first planet to form, and it contains most of the material that wasn't incorporated into the Sun. The leading theories about its formation rest on the amount of water the planet soaked up," NASA explained.
The agency's Juno mission will hopefully be able to provide that important information by mid-2016.
And of course our solar system, among countless others, cannot be alone in its water wealth. Experts have found that searching not only for the signature for water, but habitable circumstances where water could support life (i.e. - not too close, nor too far from a host star) is our best bet for finding habitable worlds outside our solar system. As things stand, NASA's Kepler satellite, which is dedicated to the task, has discovered about 1,000 planets in the Milky Way galaxy that could possibly support life, and another 3,000 objects that likewise could be habitable worlds.
With this in mind, Stofan concluded that, "in our lifetime, we may very well finally answer whether we are alone in the solar system and beyond."
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