A Salute to Cassini-Huygens and the Team Who Successfully Explored Saturn for More Than a Decade

Amid the stupidity emanating from Washington D.C. these days, depression can be a real impediment to a happy life. Other events unrelated to politics give me some sense of hope about the future of humanity, and one of those things is drawing to a close this week: the Cassini-Huygens mission to Saturn. It is one of humanity's greatest accomplishments, the extended exploration of another planet in our Solar System. I want to offer my congratulations and appreciation to the team that made this mission possible.

Source: https://nasa.tumblr.com/post/165331742919/cassini-spacecraft-top-discoveries

Have a look at this summary of discoveries from NASA; it has some astounding images.

This incredible mission resonates with me in a special way. I was a child of the 1950s, and the world and the Universe were different places in so many ways for a kid who was fascinated by astronomy. In particular, we barely knew more about our own Solar System than we did a hundred years earlier. We had made larger telescopes, but their effectiveness was limited by the disturbances in the upper atmosphere that distorted high magnification images. In those primitive years before the Hubble Space Telescope and the Voyager satellites, the science of astronomy was an exercise in frustration. I would head to the library week after week, checking out every astronomy book in the stacks, hungering to understand our own Solar System. 

Source: Unknown

How little we knew! Venus was shrouded in clouds. Mars had visible features, but they were unidentifiable from earthbound telescopes. Jupiter and Saturn had some visible cloud bands, but their moons were simple points of light. Only Saturn had rings, and maybe three divisions were visible. Neptune and Uranus were small disks, and diminutive Pluto was a dot of light. I wanted to know more!

The advances came so slowly (at least to this young growing child). The first satellite missions to Mars in the 1960s revealed surface features (and a lack of alien civilizations). Pioneer swept past Jupiter, but the camera on board was relatively primitive by modern standards. In the late 1970s, the two Voyagers began the grand tour of the outer gaseous planets. It was an excruciating wait as the small satellites passed first Jupiter, then Saturn, followed by Uranus and Neptune (years passed between each visit). Then, knowing the satellites had arrived, there was the excruciating wait for the pictures to be downloaded and processed. It was worth the wait. The pictures and data were astounding, revealing worlds never imagined by humans. The child in me was absolutely enchanted. But something still seemed to be missing.

The missions were all fly-bys. The trajectory was carefully planned to glean as much information as possible, but the satellites flew past their targets fast, and the numbers of pictures were limited by both time and technology. What was really needed was to insert a satellite in orbit, and that is a daunting challenge. The Cassini-Huygens mission accomplished that task in a spectacular manner. Check out the "ball of yarn" below...satellites can only maneuver to a very limited degree because of fuel requirements, so the crew had to aim the craft with an extreme degree of accuracy.

A computer-generated representation of all Cassini’s Saturn orbits -affectionately called the “ball of yarn” by mission planners. The time frame spans Saturn Orbit Insertion on July 1, 2004 to the end of mission on Sept. 15, 2017. Credit: NASA/JPL-Caltech

The pictures of the clouds and bands of Saturn are spectacular enough, but the real adventure of the Cassini-Huygens mission has been the exploration of the rings and moons of Saturn. Six new moons were discovered and named, bringing the total of known moons to 62, second only to Jupiter's 69. In essence, Saturn is a planetary system with one "planet" that is larger than Mercury.

This picture is not showing Mars, Venus and Earth orbiting Saturn. It's actually a view towards the inner Solar System from behind Saturn (which is hiding the Sun)

 George Lucas could barely come up with stranger moons for his Star Wars movies than the very real moons we have in our Solar System. More than enough of them are somewhat like our own Moon, cratered and "dead" (i.e. geologically inactive). But some are...very different. It turns out that Titan, the largest, has a thick atmosphere complete with rivers and streams, lakes and even a few seas. It rains and snows. That might seem a bit odd, since the surface temperature is hundreds of degrees below zero, but the liquid isn't water. It is made of hydrocarbons that on Earth would exist as gases like methane.

Saturn's moon Titan, complete with atmosphere, and shallow seas reflecting the sun.

Another major moon of Saturn, Enceladus, is even stranger, if that is possible. It's the brightest object in the Solar System aside from the Sun itself. The reason is ice. The entire crust of the "planet" is made of water ice, and it covers a "molten" layer below of salty water that may be four or five times deeper than Earth's oceans (Enceladus is much smaller than Earth, only about 310 miles in diameter).

Enceladus, the ice moon of Saturn. An incredibly deep ocean lies hidden beneath the icy crust.

The fractures and cracks in the surface, along with a relative lack of craters suggests the surface of Enceladus is tectonically active. It is simply one of the most fascinating "worlds" in our Solar System. And when I was growing up, all it was to us on Earth was a barely visible dot of light in our most powerful telescopes.

Enceladus and Saturn. Enceladus is the brightest object in the Solar System besides the Sun itself.

 Saturn is full of wonders and mysteries that are now becoming apparent to human beings for the first time in all our existence as a species. What a privilege to be living in a time when things like this can happen! And what a privilege and honor it must be to be part of the team that made the entire mission possible. And what competence! The Cassini-Huygens satellite left Earth nearly twenty years ago, and the moment it left, no repairs would ever be possible. When I consider how often my laptops and smartphones have to be replaced or repaired, just think what it means to be the inventor and maker of a complex piece of technology that has operated for twenty years with barely a glitch in performance.

Mima and Saturn

So what now? It's going to take years to interpret and present the scientific discoveries concerning Saturn, and the data will inform the objectives of future missions to the planet. But what to do in the meantime? Well, there's another really big planet out there, and a new satellite just arrived and started its explorations. It's called Juno, and the planet it is exploring is Jupiter. Jupiter has now had a number of fly-bys (Pioneer 10 and 11, and Voyager 1 and 2), and it also had an orbiter mission (Galileo). Galileo provided a treasure trove of information, and the Juno will be able to build on that (it also has a more polar orbit, providing views that the other missions could not). In other words, this very wonderful human adventure continues.

Titan and Dione with Saturn as a backdrop.

So thank you, and congratulations to the team that gifted us with the Cassini-Huygens mission to Saturn. Tomorrow, the Cassini satellite will plunge into atmosphere of Saturn at a ludicrous speed (echoes of "Spaceballs") of about 75,000 miles per hour and go out in a literal blaze of glory after 13 years of collecting data. It will be transmitting information right up to the final seconds of its existence. It was a job well done.

Star Trek at Fifty Years, and the First Week of a New Semester

Source: Copyright Paramount Pictures https://en.wikipedia.org/wiki/File:STIn_Beauty.jpg

I spent part of my evening watching some Smithsonian Channel shows regarding the 50th anniversary of the initial voyage of the Starship Enterprise on Star Trek (TOS; that's "The Original Series" for those of you who aren't Trekkies). The show was a part of my youth; I am one of those lucky people who saw at least some of the episodes during their original airings on network television. It was in black and white (in my home, anyway), but I found it fascinating. This minor television hit from the 1960s had such an optimistic view of the future of humankind, as well as being filled with really neat devices and technology.

I talk about Star Trek during the first week of every class I teach. I ask my students about their attitude towards "science", and two words invariable come up: boring and hard. As we continue a discussion about how science works we talk about how science is a body of knowledge, a codified organization of facts and principles that we agree are "real" despite the cultural background of anyone studying science. In other words, we can believe whatever we wish. We can even decide, for instance, to deny the existence of gravity. But no matter how hard one believes that gravity isn't real, one will still drop like a rock if one steps off a cliff. So we start to collectively begin to understand how science works. But still, there are challenges in learning and mastering science. It can indeed be hard (and maybe boring, but I can't imagine how...). On the other hand, what a privilege to be living in the times that we do, with the knowledge that we have access to!

This was the Solar System of my youth

That's where Star Trek comes in. Episode after episode imagined "strange new worlds", and most of them included bizarre planets far removed from our own. To me, back in those primitive years before the Hubble Space Telescope and the Voyager satellites, the science of astronomy was an exercise in frustration. I would head to the library week after week, checking out every astronomy book in the stacks, hungering to understand our own Solar System. And we knew so little! Venus was shrouded in clouds. Mars had visible features, but they were unidentifiable from earthbound telescopes. Jupiter and Saturn had spectacular clouds, but their moons were simple points of light. Nothing could be discerned on their surfaces. Neptune and Uranus were small disks, and diminutive Pluto was a dot of light. I wanted to know more!

Mars, up close. The various orbiters we've sent have mapped the surface of Mars with more detail than much of the Earth, since oceans obscure much of our own planet.

The advances came so slowly (at least to this young growing child). The first satellite missions to Mars in the 1960s revealed surface features (and a lack of alien civilizations). And in the late 1970s, the two Voyager spacecraft began the grand tour of the outer gaseous planets. It was an excruciating wait as the small satellites passed first Jupiter, then Saturn, followed by Uranus and Neptune (years passed between each visit). Then, knowing the satellites had arrived, there was the excruciating wait for the pictures to be downloaded and processed. It was worth the wait. The pictures and data were astounding, revealing worlds never imagined by humans, even on Star Trek! Volcanic moons, ice moons, cratered moons, moons with atmospheres, rivers, lakes and seas. It was a menagerie of strange new worlds, and they were in our own back yard.

Jupiter from the Galileo mission

The Voyager missions were one of humankind's greatest adventures, and they continue as the satellites actually leave the Solar System and enter interstellar space. They continue to send data, even after 39 years. And other incredible missions followed, the Galileo to Jupiter, Cassini to Saturn, the New Horizons to Pluto. And most recently, the arrival of Juno at Jupiter. We are only now seeing the first pictures.The quality of the photographs and scientific data are astounding.

From the Juno mission THIS WEEK! Our first ever view of the north pole of Jupiter.

And what about all that cool Star Trek technology? Who could have believed that some of the craziest bits of technology from the original show would be commonplace less than fifty years later. Communicators and tricorders became the flip-phones and smart phones and tablets of today. Essentially the entire library of human knowledge can be carried in anyone's pocket (and what do we do with it? Send each other pictures of kitties...priorities!).

Saturn

And this is what keeps me going every day as I approach my thirty-fifth year in the front of a classroom. The adventure in space continues, as it does in all areas of science, including my own in geology. Just in the last year we saw Pluto up close for the first time, as well as the largest of the asteroids, Ceres. More planets and planetoids remain to be discovered. The launch of the Webb Space Telescope in a few years promises to extend our vision to the edge of the known Universe. It is an incredible time to be alive! I feel privileged to have seen a vision of adventure in outer space through the many permutations of Star Trek, as well as seeing a vision of humankind at its potential best. But I'm glad I'm still around to see the real human adventure of science exploration continuing.. And that's what I hope my students will come to understand as well.

From Paramount Pictures

Thanks Gene Roddenberry, and all the cast members, living and gone, who've been part of the Star Trek universe. Happy 50th anniversary!