The team running the NASA Curiosity probe has made an amazing announcement this week, with the confirmation that the little rover has discovered organic compounds on the planet Mars. (Scientists thought they had found similar compounds two years ago, but at the time there was uncertainty whether the tests were correct)

And while this is still a long way from claiming there is life on Mars, it is worth noting that these compounds on Earth were required to form primordial life. Most likely they were delivered to the red planet on the surface of comets that impacted the planet early in its history.

So it doesn't prove life on Mars, but it proves it is possible. We will all have to wait to see what they find next...