Phosphorus, in the form of phosphates, is vital for all life on Earth. It forms the backbone of DNA and is part of cell membranes and bones. The new study, published June 14 in Nature, is the first to report direct evidence of phosphorus on an extraterrestrial ocean world.
The team found that phosphate is present in Enceladus' ocean at levels at least 100 times higher - and perhaps a thousand times higher - than in Earth's oceans.
"By determining such high phosphate concentrations readily available in Enceladus' ocean, we have now satisfied what is generally considered one of the strictest requirements in establishing whether celestial bodies are habitable," said third author Fabian Klenner, a UW postdoctoral researcher in Earth and space sciences. While at Freie Universitat Berlin, Klenner did experiments that revealed the high phosphate concentrations present in Enceladus' ocean.
One of the most profound discoveries in planetary science over the past 25 years is that worlds with oceans beneath a surface layer of ice are common in our solar system. These ice-covered celestial bodies include the icy moons of Jupiter and Saturn - including Ganymede, Titan and Enceladus - as well as even more distant celestial bodies, like Pluto.
NASA's Cassini mission explored Saturn, its rings and its moons from 2004 to 2017. It first discovered that Enceladus' harbors an ice-covered watery ocean, and analyzed material that erupted through cracks in the region of the moon's south pole.
The spacecraft was equipped with the Cosmic Dust Analyzer. which analyzed individual ice grains emitted from Enceladus and sent those measurements back to Earth. To determine the chemical composition of the grains, Klenner used a specialized setup in Berlin that mimicked the data generated by an ice grain hitting the instrument. He tried different chemical compositions and concentrations for his samples to try to match the unknown signatures in the spacecraft's observations.
"I prepared different phosphate solutions, and did the measurements, and we hit the bullseye. This was in perfect match with the data from space," Klenner said. "This is the first finding of phosphorus on an extraterrestrial ocean world."
Planets with surface oceans, like Earth, must reside within a narrow range of distances from their host stars (in what is known as the "habitable zone") to maintain temperatures at which water neither evaporates nor freezes. Worlds with an interior ocean like Enceladus, however, can occur over a much wider range of distances, greatly expanding the number of habitable worlds likely to exist across the galaxy.
In previous studies, the team at the Freie Universitat Berlin determined that Enceladus harbors a "soda ocean," rich in dissolved carbonates, that also contains a vast variety of reactive and sometimes complex carbon-containing compounds. The team also found indications of hydrothermal environments on the seafloor. The new study now shows the unmistakable signatures of dissolved phosphates.
"Previous geochemical models were divided on the question of whether Enceladus' ocean contains significant quantities of phosphates at all," said lead author Frank Postberg at Freie Universitat Berlin. "These measurements leave no doubt that substantial quantities of this essential substance are present in the ocean water."
To investigate how the ocean on Enceladus can maintain such high concentrations of phosphate, geochemical lab experiments and modeling included in the new paper were conducted by a Japan-based team led by second author Yasuhito Sekine at the Tokyo Institute of Technology and a U.S.-based team led by fourth author Christopher Glein at the Southwest Research Institute in San Antonio, Texas. Other authors are from Germany, the U.S., Japan and Finland.
Research Report:Detection of phosphates originating from Enceladus's ocean
|Subscribe Free To Our Daily Newsletters
Virgin Galactic's use of the 'Overview Effect' to promote space tourism is a terrible irony
Diving into practice
Schools, museums, libraries can apply to receive artifacts from NASA
Catastrophic failure assessment of sealed cabin for ultra large manned spacecraft
Falcon 9 deploys 53 Starlink satellites on SpaceX's 40th launch of the year
Astrobotic and Westinghouse team to power outer space
Arianespace and Orbex to explore European Launch Partnership
China launches rocket with record payload
Curiosity captures Morning and Afternoon on Mars
First Mars livestream: the movie
Artificial photosynthesis for real oxygen
How NASA gives a name to every spot it studies on Mars
Tianzhou 5 reconnects with Tiangong space station
China questions whether there is a new moon race afoot
Three Chinese astronauts return safely to Earth
Scientific experimental samples brought back to Earth, delivered to scientists
SpaceDaily.com removes all Network Advertising
Satellite swarms for science 'grow up' at NASA Ames
HawkEye 360's Cluster 7 begins operation in record time
CNES, E-Space complete next-generation low earth orbit constellation study
NASA laser communications terminal delivered for Artemis II lunar mission
Foldable phased-array transmitters for small satellites
Discharge test for launcher antenna
goTenna's mesh network demonstrates Oahu connectivity for U.S. military
Gemini North detects multiple heavier elements in atmosphere of hot Exoplanet
Elusive planets play "hide and seek" with CHEOPS
Planet orbiting 2 stars discovered using new technique
Phosphate, a key building block of life, found on Saturn's moon Enceladus
Colorful Kuiper Belt puzzle solved by UH researchers
Juice deployments complete: final form for Jupiter
First observation of a Polar Cyclone on Uranus
Research 'solves' mystery of Jupiter's stunning colour changes
|Subscribe Free To Our Daily Newsletters