Europeâ€™s Rosetta comet probe has revealed that its target, Comet 67P/Churyumov-Gerasimenko, has a Siamese twin, a thrilling discovery for scientists preparing for Rosettaâ€™s August rendezvous and a huge challenge for engineers figuring out how to land a small probe onto the comet in November.
Technically, the comet is whatâ€™s called a â€œcontact binary,â€ comprised of two differently sized nuclei joined together.
Franceâ€™s Centre National dâ€™Etudes Spatiales (CNES) released the images â€” prematurely, apparently â€” because they have since been removed from its website.Â But not before sharp-eyed Planetary Society blogger Emily Lakdawalla nabbed them, along with a press release estimating the cometâ€™s twin nucleus measures about 2 miles by 2.5 miles.
Philippe Lamy, with the Laboratoire dâ€™Astronomie Spatiale in France, apparently calculated that the comet bodies would have had to come into contact with each other at a relatively slow speed of 6.7 mph to meld together the way it has.
Like any parent confronting the prospect of twins, the surprising discovery presents complications.
Rosetta includes a small lander named Philae that is designed to harpoon itself to the cometâ€™s body several months after the mother ship reaches orbit in August. The cometâ€™s odd shape, however, could make finding a suitable landing spot more difficult.