THE deluge of images and data expected from the spacecraft Cassini as it homes in on Saturn has begun. On 11 June, Cassini flew within 2000 kilometres of the moon Phoebe, snapping images (see above) that reveal details only a few tens of metres across.
While most of the moon’s surface is dark, impacts have blasted holes in it to reveal brighter material underneath, probably a mixture of ices. That means Phoebe is similar in make-up to Halley’s comet and probably formed in the chilly outer solar system, perhaps in a reservoir of comets beyond Neptune called the Kuiper belt, to be captured by Saturn later.…
