By the time I finished high school, I knew I wanted to become an astronomer. By the time I finished college, I knew I wanted to be part of the American space program. And that's exactly what I did.
Titan is the one place in our solar system whose geographical and atmospheric diversity and complexity are rivaled only by the Earth's. It's very Earth-like, but it's also very different, which means we have a lot to learn as well as a prayer of understanding what we find.
When the Voyager 2 spacecraft sped through the Saturnian system more than a quarter of a century ago, it came within 90,000 kilometers of the moon Enceladus. Over the course of a few hours, its cameras returned a handful of images that confounded planetary scientists for years.
Voyager found Saturn to be a planet with a complex interior, atmosphere, and magnetosphere. In its rings - a vast, gleaming disk of icy rubble - the mission recorded signs of the same physical mechanisms that were key in configuring the early solar system and similar disks of material around other stars.
Every type of ring behavior we have seen around Jupiter, Uranus, or Neptune can be found in orbit around Saturn. And Saturn's ring system offers the greatest promise of understanding processes in operation within all disk systems, not just those found around planets.
The Huygens images were everything our images from orbit were not. Instead of hazy, sinuous features that we could only guess were streams and drainage channels, here was incontrovertible evidence that at some point in Titan's history - and perhaps even now - there were flowing liquid hydrocarbons on the surface.
The book that blew the doors off the house, grabbing me with its breathtakingly deep and irresistible view of the universe and our relation to it, was 'Intelligent Life in the Universe' by I. S. Shklovskii and Carl Sagan. I recall an enchanting all-nighter completing a college homework assignment to read the first chapter.
To my mind, most people go through life recoiling from its best parts. They miss the enrichment that just a basic knowledge of the physical world can bring to the most ordinary experiences.
Titan is Saturn's largest moon, and, until Cassini had arrived, there was the largest single expanse of unexplored terrain that we had remaining in our solar system.
The reasons why images are so primal and people immediately relate to it is that we are exquisitely engineered to interpret information that is arrayed in two dimensions. That's our eyesight. That's how our eye-brain system works. So it immediately feels to us when we look at an image like we have extended our senses.
As far as I'm concerned, Enceladus has become the go-to place in our solar system for issues bearing on extraterrestrial life. It's a great place to examine extraterrestrial organic chemistry that is water-based and, therefore, like biotic chemistry on Earth.
The most exciting thing that we have found with Cassini is the geological activity, the geysering activity at the south pole of Enceladus.
Between my participation in Voyager and my role in Cassini, when comes the time, I will die a happy and gratified woman.
Voyager's passage through Saturn's inner system exposed diverse moons with dynamic forces at work. Titan, Saturn's largest moon, whose surface remained invisible through its thick, ubiquitous haze, nonetheless teased observers with hints of a possible ocean of liquid hydrocarbons.
Even by the diverse standards of Saturn's satellites, Enceladus was an outlier. Its icy surface was as white and bright as fresh snow, and whereas the other airless moons were heavily pocked with craters, Enceladus was mantled in places with extensive plains of smooth, uncratered terrain, a clear sign of past internally driven geologic activity.
Titan has no liquid water on its surface, and any liquid water beneath its surface is inaccessible to us, as far as we know. It has hydrocarbon lakes, but we don't know of any organisms that could live in those, not at the temperatures that we find on Titan. Any reference to possible life in lakes on the surface of Titan is pure speculation.
The first real Cassini image that brought tears to my eyes was an image of Jupiter. I didn't expect it to look so detailed.
Saturn is such an alluring photographic target.
It's like there's a pulsating, hidden world, governed by ancient laws and principles, underlying everything around us - from the movements of electrical charges to the motions of the planets - and most people are completely unaware of it. To me, that's a shame.
The Saturn system is a rich planetary system. It offers mystery, scientific insight, and obviously splendour beyond compare, and the investigation of this system has enormous cosmic reach... just studying the rings alone, we stand to learn a lot about the discs of stars and gas that we call the spiral galaxies.
