The National Aeronautics and Space Administration (NASA) recently released new evidence that backs up supporting scientific theories that several of the moons in Earth's solar system could potentially be habitable. The new evidence was gathered using resources that NASA has available like the Hubble Space Telescope and the Cassini Space Probe. However, the main moons being focused on in the search for life are Jupiter's moon Europa and Saturn's moon Enceladus.

Jupiter's Europa

Europa is one of the Galilean moons discovered by Galileo Galilei (1564-1642) in 1610.

It is the fourth largest moon orbiting Jupiter and the sixth largest moon in the solar system. Europa's surface is covered in an icy crust that hides a massive salt water ocean that is believed to hold twice as much water as Earth's oceans.

The Hubble Space Telescope provided the new evidence that helps to back theories that life could be on Europa. Hubble spotted a massive water plume erupting from the warmest part of Europa's surface. This is the second time that a water plume has been spotted from the same location on the moon. This is causing researchers to speculate that this plume could be a constant feature, much like geysers that are found on Earth.

Saturn's Enceladus

Enceladus was discovered by William Herschel (1783-1822) in 1789.

It is the sixth largest moon orbiting Saturn and the eighteenth largest moon in the solar system. The surface of Enceladus is also covered in frozen water, as well as other icy elements, but under this is an ocean that is strikingly warmer.

The Cassini spacecraft, which has studied Saturn and its moons since 2004, used a mass spectrometer and other on-board sensors to study Enceladus to find NASA's new evidence.

These devices picked up an abundance of hydrogen molecules in the plumes of water that rise out of the cracks on the planet's frozen surface. In the past Cassini was used to help determine that Enceladus had a global ocean.

The researchers at NASA believe that the hydrogen is coming from a hydrothermal reaction happening between the ocean and the rocky core of the moon.

This prospect is exciting because it would likely mean that methane, an essential chemical for life, is forming in the ocean also. It is also possible that life could live around these potential methane vents in Enceladus' oceans, like the life found around these vents deep on the ocean floor of Earth.