Researchers have discovered that Saturn's icy moon Enceladus features hot springs, hinting that its subsurface ocean has a temperature near boiling point. This represents the first evidence that active hydrothermal vents exist beyond the Earth's oceans, suggesting that conditions similar to those that started life on Earth could be found on the moon.

Enceladus is the sixth-largest of the moons on Saturn. At just around 314 miles in diameter, it is small enough to fit within the borders of Arizona. Because it's small, the moon wasn't discovered until 1789. In 2005, however, it drew attention as NASA's Cassini spacecraft showed water geysers erupting from the moon. This is what suggested that Enceladus could have liquid water underneath its frozen crust, making it a potential host for life in the solar system.

Now that further research has been done on the geysers, it has been determined that they are powered by hydrothermal activity similar to hydrothermal vents on Earth's ocean floor. In a study published in the journal Nature, researchers detailed their analysis of dust particles observed by Cassini 10 years ago. The particles are only nanometers in size and contain rich amounts of silica, not the usual ice particles around Saturn. Silica is very common on Earth, however, occurring nearly as frequently as quartz.

About 4 to 16 nanometers in size, the particles were not only shown to have come from Enceladus but that they also require specific conditions to be produced. These conditions include: water temperature of at least 194 degrees Fahrenheit, pH levels higher than 8.5, minimum depths of 24.8 miles and salinity levels no more than 4 percent. Seawater on Earth has a salinity level of between 3.2 and 3.7 percent.

According to Gabriel Tobie, a University of Nantes planetary scientist who wrote a commentary about the study in Nature, alkaline hydrothermal vents were likely to have been the birthplace of the first living organisms on Earth.

Hsiang-Wen Sean Hsu, a University of Colorado, Boulder planetary scientist and one of the authors for the study, explained that hydrothermal systems could be the birthplace of life because they fulfill three criteria needed: liquid water, nutrients and energy. He added that there was no guarantee that Enceladus would be stable enough to allow life to form but there is a chance if active hydrothermal systems are in place.

Ralf Srama, Georg Moragas-Klostermeyer, Sin-iti Sirono, Shogo Tachibana, Tatsu Kuwatani, Yuka Masaki, Katsuhiko Suzuki, Nicolas Altobelli, Antal Juhasz, Mihaly Horanyi, Sascha Kempf, Takazo Shibuya, Yasuhito Sekine and Frank Postberg also contributed to the study.

Photo: Kevin Gill | Flickr

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