In 1997, the Cassini space probe was launched from Earth with the task of studying the elaborate ring system that surrounds Saturn. Cassini has also been looking at the planet’s moons of which 53 have been found and named.
Facts about Enceladus
Enceladus is a small moon, about 505 kilometres in diameter inside Saturn’s E ring – that’s the outermost of the eight rings that surround the planet.
The BBC’s Science and Nature website describes Enceladus as “The shiniest place in the solar system,” because it is covered with snowy water ice that “reflects virtually 100 percent of the light that falls upon it.”
Other information about Enceladus:
- The surface temperature is -201°C;
- The moon is slightly egg shaped;
- It cannot be seen with the naked eye from Earth; and,
- It was discovered until 1789 by Friedrich Wilhelm Herschel.
Cassini Probe Beams back Data
In 1981, the Voyager I spacecraft did a fly past of Enceladus and revealed that plumes of vapour were coming off the moon’s South Pole. Astronomers did not know at the time what this exhaust was made of. Now they do; it’s water.
The Cassini probe answered the question. A video at NASA’s Jet Propulsion Laboratory points out that in 2005 Cassini revealed “a hot spot at Enceladus’s South Pole…What should have been a geologically dead world appears to be active. This mysterious hot zone is the source of Enceladus’s most striking feature; towering plumes of ice particles and water vapour erupt like geysers…and extend hundreds of miles into space.”
These jets of ice particles come out of surface cracks that have been called “tiger stripes” because they resemble the marking on the big cats.
Does Enceladus Have an Underground Sea?
Writing in Time Magazine (June 26, 2009), Jeffrey Kluger says the ice particles the Cassini probe collected have taken years to analyze, but it has been worth the wait.
“Not only is the ice made of ordinary water, but it’s salt water... ‘Our measurements imply that besides table salt, the grains also contain carbonates like soda,’ says Frank Postberg, a Cassini scientist working at the Max Planck Institute in Heidelberg, Germany.”
The results of the analysis have been published in Nature (June 25, 2009), suggesting “the possibility of a subsurface ocean…It was not clear, however, whether the liquid is still present today or whether it has frozen.
Possibility of Life on Enceladus
BBC News (June 24, 2009) reported confirmation of liquid water would be “a stunning result. It means the Saturnian satellite may be one of the most promising places in the solar system to search for signs of extraterrestrial life.”
Science reporter Jonathon Amos quotes John Spencer, a Cassini scientist from the Southwest Research Institute, Boulder, Colorado as saying: “We need three ingredients for life, as far as we know – liquid water, energy, and the basic chemical building blocks – and we seem to have all three at Enceladus, including some fairly complex organic molecules.”
Spencer is quick to point out that doesn’t mean there is life on Enceladus, just that the conditions for it to be present seem to be there.
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