Mission scientist reacts to historic first images from the surface of a comet

For some comets, breaking up is not that hard to do. A new study indicates that the bodies of some periodic comets — objects that orbit the Sun in less than 200 years — may regularly split in two, then reunite down the road. This may be a repeating process fundamental to comet evolution.

Somewhat appropriately spooky for Halloween in recent radar images, 600 metre-wide near-Earth object 2015 TB₁₄₅ dashes by our planet today. Now believed to be a dead comet that has shed its volatiles after numerous passes around the Sun, the object makes its closest approach to Earth at 5pm GMT. UK observers with clear skies may see it with modest telescopes in the early evening.

Scientists from Rosetta’s OSIRIS team have discovered an extraordinary formation in the Aker region on the larger lobe of comet 67P/Churyumov-Gerasimenko. The largest of a group of three boulders with a diameter of approximately 30 metres appears to perch on the rim of a small depression. There seems to be only a very small contact area with the nucleus.