Free Astronomy Magazine September-October 2014

7 Aug 2014; distance: 104 km. It is in this spectacu- lar shot that can be best un- derstood the possible dy- namics that originated the unusual nucleus. Sand and rocks have crashed toward the probable collision point between the two main blocks. [ESA/Rosetta/MPS for OSI- RIS Team MPS/UPD/LAM/IAA/ SSO/INTA/UPM/DASP/IDA] emitted by its own engines. Apart from pollutants, the cometary activity between April and June appeared quite variable, with a rapid increase of the coma, then re- turned to its original level in the following weeks, when the focus shifted to its nucleus, that in the images taken on 28 June by OSI- RIS from a distance of 86,000 km began to reveal an asymmetrical form, later confirmed by a series of images shot on 4 July from 37,000 km away, in which the nucleus cov- ered an area of 30×30 pixels, sufficient to determine that its actual rotation period is 12.4 hours. The real form of 67P/Churyu- mov-Gerasimenko though began to emerge on 14 July, when OSIRIS captured a new se- ries of images in which the comet appeared with a rather irregular surface but, in par- ticular, with an entirely unexpected overall structure, consisting of two clearly distin- guishable parts. It is no news that the small bodies in the solar system can take forms