Counting Down The Moons

Obviously, the Earth’s Moon is pretty great, as moons go. For the broad sweep of human history, this beacon of our night sky has inspired lovers and songwriters and literature, encouraged early humans to develop calendars and create the science of astronomy, influenced the tides of our oceans, and provided a bright light to help illuminate the dark night and early morning hours. For a dead, lifeless celestial body that is pockmarked with craters, that’s a pretty impressive list of achievements.

To the folks at Popular Mechanics, though, our Moon isn’t at the top of the lunar heap. When they decided to sit down and rank the more than 150 moons in the solar system — including ones you’ve probably never heard of, like Epithemius and Janus, which share the same orbit around Saturn, Dactyl, a moon that actually orbits an asteroid rather than a planet, and Mimas, which looks uncomfortably like the Death Star from Star Wars — our Moon didn’t fare very well. In fact, the Moon barely cracks the top ten, coming in at number 8. The Popular Mechanics crew concludes that it’s just not as interesting from a scientific standpoint, or as charismatic, as other moons. In fact, you get the sense from the comments reported in the article that the number 8 slot is actually kind of a pity ranking, given just because the Moon is our moon and we give it a capital M. The Old Man in the Moon has got to be disappointed.

The Moon came in behind Iapetus, Ganymede, Europa, Triton, Enceladus, Io, and the top-rated moon, Titan, which also orbits Saturn. These bodies all have features the Moon lacks, like liquid oceans, actual atmospheres made up of exotic combinations of chemicals, volcanic activity, bright colors, or the possibility of alien life.

OK, I get it: but has anyone ever actually written a song about Enceladus, or Titan?

Titanic Indications of Extraterrestrial Life

The Daily Mail has an interesting piece today on tantalizing indications that there might be a form of life on Titan, a moon that orbits Saturn.  Titan is one of the largest moons in the solar system and has a dense atmosphere.

The Daily Mail piece reports on two articles recently published in scientific journals that attempt to find evidence of life by focusing on the presence and absence of certain elements and chemicals.  One article notes that hydrogen that is found in Titan’s atmosphere seems to disappear when it reaches the surface and posits that a potential explanation is that the hydrogen is breathed, or otherwise consumed, by life forms on the surface.  The second article suggests that a similar conclusion could be inferred from the absence of still another chemical on the surface.

It is always risky to make broad extrapolations based on the absence of something, but the scholarly articles and the indicators they highlight are intriguing.  They confirm, once again, that exploring the moons of Saturn and Jupiter could be tremendously rewarding from a scientific standpoint.  If there is life on Titan, however, it would be quite different from life on Earth.  Although there is liquid on Titan, the liquid is methane, and scientists think life would be methane-based.

To Sail On Distant Seas

Artist's depiction of the surface of Titan

Here’s a pretty cool space exploration idea:  land a craft on one of the seas on Titan, Saturn’s largest moon.  Because Titan is so cold, the seas aren’t filled with water, but with liquid hydrocarbons, including methane, ethane, and propane.  (Hank Hill no doubt would support the idea.)  NASA thinks Titan may have more hydrocarbons than Earth has oil and natural gas.

The Titan exploration proposal would be pretty cheap by modern standards, costing only a few hundred million dollars — about the price of a Senator’s vote for the health care bill.  And it has the advantage of being creative and evocative, drawing on the rich history of Earth exploration by sailing ships.