Environment

Alien Clues From Deep-Sea Life

Earth's deep-sea life hints at what alien life might look like.

Enceladus, Saturn’s white moon, emits hydrogen molecules which have been found in the icy water that is expelled from the moon’s crust. The hydrogen molecules are suggestive of hot spots in a hidden ocean. The hot spots are similar to the hot spots of earth’s hydrothermal vents which support the life of several deep-sea animals. Hydrogen is a source of food for microbes, and therefore the presence of hydrogen on Enceladus may suggest the presence of microbes that feed on hydrogen. There is still no proof of the presence of microbes in Enceladus, but the presence of hydrogen makes it more probable. Hunter Waite, a leading investigator, states that if earth’s microbes were taken there, they would most likely survive.

Hydrothermal Vents

It was accepted among the scientific community that almost all life on earth obtained energy from the sun in one way or another. However, this theory was turned on its head with the discovery of tube worms at hydrothermal vents deep underwater. In 1977, an expedition sponsored by the National Oceanic and Atmospheric Administration discovered an unexpected community of giant tube worms among other crustaceans and molluscs living near hydrothermal deep-sea vents along the Galapagos Rift. The vents, known as black smokers, were at a depth of 2,000 m and emitted strongly acidic water with a pH of 2.8 superheated to 400°C.

Deep-sea hydrothermal vents are known as black smokers or white smokers based on the type of mineral they emit. Black smokers are typically found at depths of 2500 to 3000 m although the deepest known sits at a depth of 5,000 m. They are named for the black, smoke-like water that is emitted from the chimney-like structure due to the presence of sulfur-bearing minerals.

Deep-Sea Life

Previous to the 1977 discovery, deep-sea life was thought to obtain their energy from the sun, through marine snow, organic matter that fell from the upper layers. Instead, the discovery exposed the existence of ecosystems reliant on the hydrothermal vents. The area surrounding the hydrothermal vents was found to have a density of 10,000 to 1000,000 times more organisms than the surrounding sea floor. The mineral-rich waters of the hydrothermal vents support large populations of chemoautotrophic bacteria which in turn supports populations of larger organisms.

Alien Clues From Deep-Sea Life

The findings are from NASA’s spacecraft Cassini which, since 2004, has been exploring the Saturn system. The findings bring researchers a step closer to proving that the moon can support life. The discovery of an ocean below the surface of Enceladus increased the profile of the moon as water is crucial to life on earth. Cassini discovered more organic chemicals like methane and several others which support life from the water occasionally spewed out by the planet. Hydrogen, carbon, oxygen, and nitrogen have been found on Enceladus. The hydrogen discovered in Enceladus was high which may also suggest the absence of any microbes or life because if there were any microbes, they would be feeding on the hydrogen and therefore decreasing the levels. Waite states that maybe the number of microbes present is negligible or there may be a missing element needed for life to survive on Enceladus.

The spacecraft Cassini came close to answering a lot of questions about the probability of life on the planet Saturn. On April 22, 2017, the spacecraft was starting its final tour around Saturn before its end. Cassini would take 22 orbits around Saturn and its rings before being destroyed. The destruction would prevent it from floating into Enceladus or Titan, Saturn’s other moon, and polluting them with earth life.

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