Rosetta Photographs Its Own Shadow On Comet 67P/C-G

mpicpp notes an image release from the European Space Agency showing the shadow of its Rosetta probe on the comet it's currently orbiting. The probe snapped the picture from a very low flyby — only six kilometers off the surface. The image has a resolution of 11cm/pixel. The shadow is fuzzy and somewhat larger than Rosetta itself, measuring approximately 20 x 50 metres. If the Sun were a point source, the shadow would be sharp and almost exactly the same size as Rosetta (approximately 2 x 32 m). However, even at 347 million km from 67P/C-G on 14 February, the Sun appeared as a disc about 0.2 degrees across (about 2.3 times smaller than on Earth), resulting in a fuzzy “penumbra” around the spacecraft’s shadow on the surface. In this scenario and with Rosetta 6 km above the surface, the penumbra effect adds roughly 20 metres to the spacecraft’s dimensions, and which is cast onto the tilted surface of the comet.

Comments

There is science here

[hamjudo]

This is more than just a selfie, the shadow cast by a known object adds depth, scale, and many other scientifically interesting details about the comet, and about the space craft itself.

And for those who like science fiction... If any aliens are riding the Rosetta probe, they will have to duck while the picture is being taken.