Where did the two tiny moons of Mars, Phobos and Deimos, come from? They were long thought to be captured asteroids, but new evidence from Mars-orbiting spacecraft suggests they result from a cataclysmic impact on the planet itself. The discovery on the surface of Phobos of minerals that formed in the presence of water gives strength to the idea that the moons were born from their host planet. Streaked with impact craters, Phobos certainly has suffered a tumultuous past. We should get first-hand information on it, including samples from its surface, when the Russian probe Phobos-Grunt gets there in the next few years. This talk explored the characteristics of the moons of Mars, and tried to solve the mystery of how they came to be orbiting the red planet.
Dr Emily Baldwin is Astronomy Now's Website Editor and Deputy Editor. She completed a PhD in impact cratering at University College London in 2008. Emily is a keen advocate of promoting the wonders of space to young people and the general public, and fulfills this role as the director for the Society for Popular Astronomy's youth section, the Young Stargazers, as well as giving talks to local astronomy societies.