Data from NASA's Cassini mission revealed that water found on Saturn's moon Enceladus contains nitrogen and oxygen compounds - the building blocks for DNA - are present in plumes of liquid water that shoot into space from the salty ocean below Enceladus's surface.
NASA scientists' suspect that such compounds could undergo chemical reactions near deep-sea hydrothermal vents on Enceladus, which could lead to life.
On Enceladus, jets of ocean water often shoot out into space through small cracks in the moon's surface. The scientists behind the new study analyzed data on the chemical composition of those plumes, and found several new organic compounds, including some that contained nitrogen and some containing oxygen.
Scientists have believed that the ocean below Enceladus's surface could harbor the ingredients for life. Researchers had previously found other organic molecules coming from the icy moon before, but this is the first time anyone has detected them dissolved in the water plumes that jet to the surface. This suggests that the compounds could undergo deep-sea chemical reactions that produce amino acids, which are complex molecules that serve as the building blocks of proteins. Without proteins, life as we know it on Earth couldn't exist.
These findings were published Wednesday in the journal Monthly Notices of the Royal Astronomical Society.
"This work shows that Enceladus' ocean has reactive building blocks in abundance, and it's another green light in the investigation of the habitability of Enceladus," Frank Postberg, a co-author of the study, said in a press release.
"Here we are finding smaller and soluble organic building blocks — potential precursors for amino acids and other ingredients required for life on Earth," Jon Hillier, another co-author of the study, said in the release.
This process allows life to develop without the assistance of sunlight, which is necessary because Enceladus's ice surface is essentially a reflective surface and sends what little sunlight the moon receives back into space. Any life there would have to develop in the dark.
"If the conditions are right, these molecules coming from the deep ocean of Enceladus could be on the same reaction pathway as we see here on Earth," Nozair Khawaja, who led the research team behind the latest discovery, said in a release. "We don't yet know if amino acids are needed for life beyond Earth, but finding the molecules that form amino acids is an important piece of the puzzle."
The data scientists used came from NASA's Cassini space probe. The probe launched in 1997 and spent 13 years exploring Saturn and its moons. In September 2017, the mission ended when scientists intentionally sent the spacecraft plummeting into Saturn. They did this to avoid contaminating Enceladus or Titan, another nearby moon that could also harbor life, with Earthly microbes.