Enceladus likes Saturn, so he put a ring on it.
I’m sure you need a minute to recover from the side-splitting laughter induced by that six year-old pop culture reference. Take your time. Good? Okay, let’s proceed. It’s been a big year for water. We’ve been melting a lot of the frozen kind here on Earth, and finding the liquid kind off-planet. NASA’s latest discovery takes us out even further out in the solar system; all the way to Enceladus.
The Cassini spacecraft has been orbiting Saturn, its moons, and its rings for the past ten years. After capturing some incredible images of geysers spouting water from Enceladus’ south pole, the probe orbited the moon. The Cassini probe, launched in 1997, has some impressive technology. It can determine the distribution of mass of the moons it orbits by measuring the varying gravitational strengths of the areas it flies over. Scientists can learn all about the the internal structure of the moons, just by seeing how the probe reacts.
It took only three orbits of an altitude of less than 62 miles (100 km) to determine that the south pole of Enceladus had more gravitational pull than its surface revealed. Scientists determined that the most likely cause was a massive subsurface ocean. A body of water about the size of Lake Superior is likely trapped 18 to 24 miles deep, between the moon’s icy crust and the rocky core. Lake Superior doesn’t seem like a massive ocean, until you realize that Enceladus’ diameter is just over 300 miles, and Lake Superior is 350 miles across.
The gravity of Saturn causes Enceladus to bend and distort as it orbits. This friction heats up the tiny moon’s core, resulting in the subsurface ocean. The geysers and the “tiger stripe” fractures they spurt from are also caused by the incredible forces of the massive gas giant. It’s unclear at the moment whether the moon would be able to harbor life. We’ll learn more as Cassini continues to orbit the Saturnian system.