NASA's best image so far from the Hartley 2 encounter
NASA's best image so far from the Hartley 2 encounter

This morning’s close up view of Comet Hartley 2 by NASA’s Deep Impact/Epoxi spacecraft reveals a complex and highly active object.

The smooth ‘neck’ of the comet nucleus is about 400 metres in diameter and the long axis appears to be around 2200 metres or roughly as calculated earlier.

NASA will release more images in the near future.

The ‘smoothness’ of the narrow section is similar to that seen on the elongated Itokawa asteroid that was visited by Japan’s Hayabusa probe in 2005. That was found to be the result of very fine grains of matter migrating over time to the lowest points of the asteroid when nudged by a combination of weak gravity and the ‘wind’ of solar particles acting over very long periods.