Studying the known universe is always interesting, mainly because you never know what you’re going to find. And just when you think you’ve got something figured out – like a moon in orbit around one of the Solar Systems more distant planet’s – you learn that it can still find ways to surprise you. And interestingly enough, a few surprises have occurred back to back in recent weeks which are making scientists rethink their assumptions about these moons.
The first came from Io, Jupiter’s innermost moon and the most volcanically active body in the Solar System. All told, the surface has over 400 volcanic regions, roughly 100 mountains – some of which are taller than Mount Everest – and extensive lava flows and floodplains of liquid rock that pass between them. All of this has lead to the formation of Io’s atmosphere, which is basically a thin layer of toxic fumes.
Given its distance from Earth, it has been difficult to get a good reading on what the atmosphere is made up of. However, scientists believe that it is primarily composed of sulfur dioxide (SO2), with smaller concentrations of sulfur monoxide (SO), sodium chloride (NaCl), and atomic sulfur and oxygen. Various models predict other molecules as well, but which have not been observed yet.
However, recently a team of astronomers from institutions across the US, France, and Sweden, set out to better constrain Io’s atmosphere. Back in September they detected the second-most abundant isotope of sulfur (34-S) and tentatively detected potassium chloride (KCl). Expected, but undetected, were molecules like potassium chloride (KCl), silicone monoxide (SiO), disulfur monoxide (S2O), and other isotopes of sulfur.
But more impressive was the team’s tentative of potassium chloride (KCl), which is believed to be part of the plasma torus that Io projects around Jupiter. For some time now, astronomers and scientists have been postulating that Io’s volcanic eruptions produce this ring of plasma, which includes molecular potassium. By detecting this, the international team effectively found the “missing link” between Io and this feature of Saturn.
Another find was the team’s detection of the sulfur 34-S, an isotope which had previously never been observed. Sulfur 32-S had been detected before, but the ratio between the 34-S and 32-S was twice that of what scientists believed was possible in the Solar System. A fraction this high has only been reported once before in a distant quasar – which was in fact an early galaxy consisting of an intensely luminous core powered by a huge black hole.
These observations were made using the Atacama Pathfinder Experiment (APEX) antenna – a radio telescope located in northern Chile. This dish is a prototype antenna for the Atacama Large Millimeter Array (ALMA). And while Io is certainly an extreme example, it will likely help terrestrial scientists characterize volcanism in general – providing a better understanding of it here on Earth as well as outside the Solar System.
The second big discovery was announced just yesterday, and comes from NASA’s Cassini space probe. In its latest find investigating Saturn’s largest moon, Cassini made the first off-world detection of the molecule known as propelyne. This simple organic compound is a byproduct of oil refining and fossil fuel extraction, and is one of the most important starting molecules in the production of plastics.
The molecules were detected while Cassini used its infrared spectrometer to stare into the hydrocarbon haze that is Titan’s atmosphere. The discovery wasn’t too surprising, as Titan is full of many different types of hydrocarbons including methane and propane. But spotting propylene has thus far eluded scientists. What’s more, this is the first time that the molecule has been spotted anywhere outside of Earth.
These finding highlight the alien chemistry of Saturn’s giant moon. Titan has moisture and an atmosphere, much like our own, except that its rains are made of hydrocarbons and its seas composed of ethane. Scientists have long wanted to explore this world with a boat-like rover, but given the current budget environment, that’s a distant prospect. Still, sales of propylene on Earth are estimated at $90 billion annually.
While no one is going to be mounting a collection mission to Titan anytime soon, it does offer some possibilities for future missions. These include colonization, where atmospheric propylene could be used to compose settlements made of plastic. And when it comes to terraforming, knowing the exact chemical makeup of the atmosphere will go a long way towards finding a way to make it breathable and warm.
And in the meantime, be sure to enjoy this video about Cassini’s latest discovery. With the government shutdown in effect, NASA’s resources remain offline. So we should consider ourselves lucky that the news broke before today and hope like hell they get things up and running again soon!
Sources: universetoday.com, wired.com