At a Glance

NASA has announced the discovery of water under the icy surface of two moons.Both moons have underwater vents, which suggests a heat source capable of sustaining life.Life has not been discovered on either moon; additional missions will be needed to find living organisms.

Plumes spewing from Saturn moon Enceladus and Jupiter moon Europa are proof of vast oceans of liquid water underneath their icy surfaces, NASA announced at a Thursday news conference.

Hydrogen, a key building block for organisms, was detected in the plumes on Enceladus, though the presence of life has not been confirmed. The plumes are 98 percent water, the agency also said, which suggests the moon has a very large ocean.

"Enceladus has almost all the ingredients you'd need to support life as we know it on Earth," said Linda Spilker,Cassini Project Scientist at the Jet Propulsion Laboratory.

This diagram shows the believed composition of Saturn's moon Enceladus, with water under its icy surface.

(Screenshot via NASA)

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The discovery of water on Enceladus was made by the Cassini spacecraft, which has studied Saturn and its moons for the past 13 years. Its mission will end Sept. 15 when it is crashed into the surface of Saturn.

NASA also announced the discovery of a massive ocean – one that likely contains twice as much water as all of Earth's oceans combined – under the icy surface of Europa, one of thedozens of moons that orbit Jupiter. Scientists believe the entire moon is covered by this ocean, which was discovered thanks to an erupting water plume that was spotted by the Hubble Space Telescope.

Both discoveries are proof ofheat sources below the surface that, combined with the presence of hydrogen and several other elements, could be enough to sustain life in the absence of sunlight, similar to deep underwater vents on Earth.

"With this research, we're taking a big step forward toward the answer to the question: Isthere life out there?" said Thomas Zurbuchen, Head of NASA Science Mission Directorate.

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An astronaut captured this photograph of Utah’s Green River doubling back on itself—a feature known as Bowknot Bend—from the International Space Station on January 22, 2014. (NASA)