67P reveals recipe for a comet
Take two smaller comets and add a cosmic smashup

TWO FOR ONE The two lobes of comet 67P, seen in this August 2014 image from the Rosetta spacecraft, probably came from two different comets, a new study suggests.
MPS for OSIRIS Team/Rosetta/ESA, MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA