Could Well Be!

The more we explore the outer solar system with probes like the Cassini spacecraft, the cooler things we discover. This week planetary scientists working with data from that spacecraft announced that there’s a good chance Saturn’s moon Titan has a layer of liquid water hidden beneath that desolate icy surface.

The discovery came from the study of tides on Titan.  This moon is squeezed and stretched as it orbits Saturn, and that is bound to cause some heating in the core.  It’s also a shape-changing process.

The scientists figured out that Titan is not a big rocky ball that would show a slight bulge on its surface as Saturn’s strong gravitational pull tugged on it.  The way they did this is quite ingenious.  They looked at Titan during its 16-day orbit of Saturn.  As it whirls around the huge planet, Titan’s shape changes and scientists could chart those changes.  Titan is not a perfectly round sphere. Instead, it’s slightly elongated like a football. As it orbits Saturn, its  long axis grows when it’s closer to Saturn. Eight days later, when Titan is farther from Saturn, it’s much less elongated and more nearly round. Cassini measured the gravitational effect of that squeeze and pull.  These measurements and the assessment of Saturn’s gravitational pull on Titan provide the best data yet of  Titan’s internal structure and what they show is that for the shape to change as much as it does, Titan likely has a an ocean layer.  It’s not necessarily a huge or deep one, but the fact that it’s there at all is one more step in learning more about Titan’s structure.

Now, I read a few stories here and there about how this supposed ocean is darn near proof that life could exist on Titan.

Not so fast.  The presence of a subsurface layer of liquid water at Titan is not necessarily an indicator for life. There are still a lot of studies to be done before scientists understand what Titan looks like in its interior, and whether or not the conditions are right for life to exist in that ocean, or perhaps at a rock-water interface deep inside.

The implications of an ocean in Titan is an exciting finding, no matter what else is discovered there. This mysterious, cloudy world is slowly yielding up its secrets, and in the process, is opening our minds about what other surprises we’re going to find in, on, or near the worlds of the outer solar system.