The European Space Agency’s Mars Express orbiter, shown in this artist’s conception, has been circling Mars since 2003. (Spacecraft image credit: ESA / ATG Medialab; Mars: ESA / DLR / FU Berlin, CC BY-SA 3.0 IGO)
It may sound like an April Fool’s joke about flatulent aliens, but this is serious: The science team behind the European Space Agency’s Mars Express orbiter thinks they know where a smelly outburst of Martian methane came from.
Any joke would fall flat, because the proposed explanation is purely geological rather than, um, biological.
The source of Martian methane has been a mystery for 15 years, thanks in part to earlier findings from Mars Express.
Back in 2004, readings from the orbiter’s instruments as well as ground-based observations picked up signs of the gas in Mars’ atmosphere. The findings raised eyebrows, because methane molecules wouldn’t persist for a long time in the air before breaking down.
That suggested there had to be some sort of source expelling the gas. And on Earth, some of the best-known sources are the digestive tracts of animals as well as methane-generating bacteria.
Identifying the source has been on the agenda for Mars missions launched since then, including ESA’s ...