The Potential Habitability of Europa's Oceans
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The Enigmatic Ocean of Europa
Recent research indicates that the hidden oceans of Europa might support life. This finding stems from a groundbreaking model created by NASA, which suggests the moon could be more habitable than previously thought. Europa, with a diameter of 3,100 km (1,900 miles), is the fourth-largest moon orbiting Jupiter and, while smaller than Earth's Moon, is larger than Pluto.
The Voyager and Galileo missions have provided invaluable data, unveiling extensive reservoirs of water beneath Europa's icy crust. However, the specific chemical composition of these alien oceans remains largely unknown. Researchers at NASA’s Jet Propulsion Laboratory utilized insights from the Galileo mission to replicate the environmental conditions beneath these extraterrestrial waters.
Europa, one of Jupiter's four largest moons, is emerging as a prime candidate in the search for extraterrestrial life, as indicated by a new study from NASA. Image credit: Europa Galileo NASA/JPL-Caltech/SETI Institute
Orbiting Jupiter at a distance five times greater than that of Earth from the Sun, Europa appears frozen at first glance. Yet beneath its icy exterior lies a vast ocean that dwarfs Earth's. The immense gravitational pull from Jupiter, coupled with radioactive decay, generates heat that melts the ice, creating these expansive underwater realms. This heating process also interacts with mineral deposits, releasing water into the ocean.
"We successfully modeled the physical properties and composition of the core, silicate layer, and ocean," explains Mohit Melwani Daswani, a geochemist and planetary scientist at JPL. "We discovered that different minerals release water and other volatile compounds at varying depths and temperatures."
The analysis revealed a close match between the mass expected to be absent from Europa's crust and the mass of its oceans, suggesting that the moon's water originates from its own mineral deposits.
The study also hints that exoplanets circling other stars might similarly generate water through the interplay of chemical and physical processes occurring within their mineral compositions.
A Vast Ocean Beneath the Ice
Discovered by Galileo Galilei in 1610, Europa is the smallest of Jupiter's four largest moons. Since its discovery over four centuries ago, it has captivated scientists' imaginations.
"Scientists estimate Europa's ice shell to be between 10 to 15 miles (15 to 25 kilometers) thick, floating atop an ocean that stretches 40 to 100 miles (60 to 150 kilometers) deep. Thus, although Europa's diameter is merely a fourth of Earth’s, its ocean may hold twice the volume of all Earth’s oceans combined," NASA explains.
Despite being as old as the solar system itself—approximately 4.5 billion years—the surface of Europa is relatively young, ranging from 20 to 180 million years.
Far from a barren landscape, Europa is adorned with intricate features and stunning details.
The magnetic field surrounding Europa provides compelling evidence for a liquid water ocean situated beneath its icy shell. This moon could represent one of the most promising locations in our Solar System to discover life, and the latest study enhances the viability of such a possibility. While earlier hypotheses suggested that the oceans might be rich in sulfur, this new model proposes that Europa's waters are more akin to Earth's salty seas, enriched with chlorides.
Research indicates that hydrothermal vents, similar to those found on Earth, could exist on Europa's ocean floor, supplying essential chemicals and warmth to its alien waters.
Comets, attracted by Jupiter's immense gravitational force, bombard Europa in large quantities, many of which carry organic materials, potentially delivering the fundamental components of life.
Moreover, chemical reactions on Europa generate ten times more oxygen than hydrogen, a factor that may significantly increase the chances of life evolving on the moon. However, the exact temperatures of these heating sources remain a mystery, warranting further exploration.
The Europa Clipper Mission
Several spacecraft have previously explored this intriguing Jovian satellite. Pioneer 10 was the first to capture images of Europa as it passed Jupiter, albeit from a considerable distance, while Pioneer 11 followed closely behind the next year.
Voyager 1 and 2 flew past the Jupiter system in 1979, with Voyager 2 discovering dark lines on the moon's surface, hinting at cracks indicative of a subsurface ocean. The Galileo mission, which orbited Jupiter from 1995 to 2003, confirmed the presence of these oceans.
The allure of deeper exploration of Europa is undeniable. NASA's Europa Clipper mission is slated for launch between 2023 and 2025, aiming to delve further into this moon's potential for life.
"Europa stands as one of our best prospects for discovering life within our solar system," Deswani notes. "The Europa Clipper mission will launch soon, and we are preparing to investigate the moon's habitability."
Equipped with nine scientific instruments, the Europa Clipper will include cameras, thermal detectors, magnetometers, and radars to penetrate the icy shell. The spacecraft is expected to complete more than 40 orbits around Europa, flying at altitudes ranging from 25 to 2,700 km (16 to 1,700 miles) above the surface, thereby minimizing its exposure to harmful radiation.
Additionally, the JUpiter Icy Moons Explorer (JUICE), anticipated to launch in the coming decade, will search for organic molecules on Europa, particularly those linked to life.
This recent research is currently under discussion at the Goldschmidt Virtual Conference, taking place from June 21–26, 2020.
James Maynard is the founder and publisher of The Cosmic Companion, residing in Tucson, Arizona, with his wife, Nicole, and their cat, Max.
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