Satellite Imagination: The Dutch Connection

With my daughter’s telescope, I can barely pick out Titan. It moves a lot more slowly in its orbit than Jupiter’s moons. We certainly can’t detect that pretty orange atmosphere. It’s just a point of light. In the image to the left, just a small smudge.

If I use my imagination, we’re chumming with Christiaan Huygens, discoverer of Titan (1655), about two generations after Galileo, and a few hundred miles north in the Netherlands.

Peering through the scope, Brittany notices that band of ice girdling the planet. “Those are the rings, right Dad?”

Huygens figured those out, too. Galileo thought of them as ears. My daughter laughs at that. “What else can we see, Dad?” she asks. And it’s off for another adventure.

Titan was left unnamed for the first two centuries of its Earthling acquaintance. Luna Saturni was enough for the Dutch astronomer. When other moons were discovered, Titan was given a roman numeral, first II and then IV. For the early 1800’s, it was known as Saturn VI. The numbering convention was I for the innermost moon, and everything else lining up in order. Not very imaginative. And a pain when astronomers kept discovering moons closer in and re-numbering the whole lot.

John Herschel, son of Uranus discoverer William Herschel, began to suggest names for the moons of the outer planets in the mid 19th century. Being the brightest and presumably the largest of Saturn’s moons, it got the name “Titan” not only for its size, but for the association of the Titans with the god Saturn.

After another century, another Dutch-born astronomer, Gerard Kuiper (left), probed Titan with spectroscopic instruments and determined the moon had an atmosphere containing methane.

Until the Voyager probes arrived in 1980 and 1981, Titan was thought to be the largest moon in the solar system. As it happens, the highest level of haze in the atmosphere rises a bit more than a hundred miles above the surface. For both mass and size, Ganymede is slightly larger than its colder, orange rival.

Titan would be a wondrous adventure for any human beings fortunate enough to get there. The Huygens probe, (a replica of which is on the right) built by the European Space Agency, was a master stroke in the exploration of space.

Piggybacking on the NASA Cassini probe, Huygens completed an amazing mission parachuting through an atmosphere and beaming back amazing images of another world.

Scientists are already applying their imaginations for a follow-up mission to Titan. Tibor Balint illustrates one intriguing idea, a hot air balloon:

The idea is to float a probe a few miles above the surface, safely above any low mountains or hills. With a heat source, no need to worry about a limited supply of ballast; just turn the burner on or off depending on something automatic like radar or air pressure. A radioactive source would last for months, maybe years. Because of the great distance to Titan, the probe would need to be almost 100% automated. If Earthling observers saw a mountain coming up, it would take over an hour to send a radio message like “Look out!” By then, our intrepid balloon would be toast, though at a frigid 290F below zero.

Here’s a Cassini image to wrap up this edition of satellite imagination. What a beautiful color for a moon. What wonders must exist under those clouds.