Episode 09: Life on Mars?

A few weeks ago NASA gathered journalists from across the globe for an announcement about something they'd found on Mars. Naturally, the collective imagination went *nuts*, because surely, SURELY this was going to be The Big Announcement: finally, the discovery of Life Elsewhere In The Universe! Turns out, nope ... but NASA did have some very cool things to talk about. Curiosity, the Mars Rover that just keeps on keeping on, has found seasonal changes in methane levels, which *could* be produced by biological mechanisms. It also found a bunch of interesting organic molecules in the martian soil. Neither of these discoveries say that life ever existed on Mars, but they're both tantalising whispers urging us to keep looking, keep looking ...