One of Saturn’s Moons Has All The Essential Elements for Life

Saturn’s moons have been under Cassini’s watch for nearly a decade, but never have we been more interested. As the search for extraterrestrial life goes above and beyond, we look beneath the icy moon’s shell to find signs of life, or simply the elements that suggest the sustenance of a species.

Jun 18, 2023 | Deep Dark Space

An illustration of Enceladus, one of the moons of Saturn.

Image by NASA

Enceladus is just 310 miles across, dwarfing in comparison to Saturn’s largest moon, Titan, boasting a radius of nearly 1,600 miles. While the icy moon reflects almost all the sunlight hitting its surface, the area hidden beneath the ice holds much more than one would expect.

For 13 years, NASA’s $4 billion-plus Cassini spacecraft orbited Saturn – uncovering wonders of the gas giant and its icy moons. Expending all its fuel by 2017, Cassini executed the “Grand Finale,” plunging into the planet’s atmosphere to ensure it would never crash into one of the planet’s moons and contaminate them with earthly germs.

Prior to its dramatic (and intentional) crash, the Cassini spacecraft shared data that changed our perception of Enceladus – one of the ice-covered moons that may contain the essential building blocks of life.

What’s so interesting about a moon?

A measly 310 miles in diameter, Enceladus (pronounced ‘en-SEL-ah-dus’) is not even Saturn’s largest moon. A surface covered by thick ice that reflects almost all the sunlight that reaches it, Enceladus does not make a strong case for itself as a place that we (or anyone else) may inhabit. But things aren’t how they seem on the surface (literally).

  • In 2015, Cassini made the monumental discovery that Enceladus may contain the necessary components of life: water, carbon, nitrogen, oxygen, hydrogen, and energy.
  • By plunging into the plumes erupting from the cracks in its frozen crust, the Cassini spacecraft discovered that the icy moon hides a saltwater ocean beneath its ice shell.
  • Studying the jets of ice and gas ejecting from the moon’s south pole, scientists have discovered phosphorus, one of the key ingredients of life as we know it.

The study published in Nature on Wednesday suggests that Enceladus shows the presence of phosphorus in the form of sodium phosphates, and in concentrations at least 100 times higher than all the Earth’s oceans combined.

Infrared views of Saturn's moon Enceladus.

These images of Enceladus were made from Cassini’s Visible and Infrared Mapping Spectrometer (VIMS), which showed the geologic activity ongoing at the moon’s south pole, with plumes of vapor shooting out from cracks in the icy crust.

Image by NASA

The big deal with phosphorus.

You might easily overlook an element that is one of the major components of animal manure — and you might be largely ignorant of its significance if you paid no attention in your biology class.

Along with carbon, hydrogen, oxygen, nitrogen, and sulfur, phosphorus makes up the sextet that we know as the essential elements for life and is a key element of DNA and other cellular components.

Surprisingly, we’re already approaching what scientists like to call “peak phosphorus.”

  • With over 70 percent of the global phosphorus supply coming from the phosphorite mines in Morocco, scientists have been warning of demand exceeds supply – which may occur around 2030.
  • Despite supporting life on Earth, phosphorus has never been detected in an ocean beyond Earth. However, these findings suggest that phosphorus is not the limiting factor we thought it was.

A previous study suggested that phosphorus is expected to be the limiting factor when it comes to “life as we know it” outside of Earth, which no longer seems to be the case.

Of course, what still evades us is the basic understanding of “life” itself  — with scientists now exploring the idea of extraterrestrial life that may lack DNA or RNA, or “extraterrestrial life as we don’t know it.”

Saturn’s moons aren’t hiding any aliens beneath the ice.

Of course, Cassini’s findings do not mean that Saturn’s moon is inhabited by some life forms. All it means is that the possibility of finding life somewhere in space is much greater than we expected.

“Enceladus discoveries have changed the direction of planetary science,” said Linda Spiker, Cassini project scientist in a statement, adding that these findings “point to the possibility of a habitable ocean world well beyond Earth’s habitable zone. Planetary scientists now have Enceladus to consider as a possible habitat for life.”

The Search for Extraterrestrial Life, or SETI, has seen vast advancements as we get increasingly prepared to look for what might be out there. Be it sending optical telescopes where no man has gone before, or sending mysterious messages across space, we’re more equipped than ever.