You'll get used to the Russian name of this comet as it approaches Mars in October. According to the European Space Agency (ESA) the comet is losing the equivalent of two tumblers of water per second – which is a lot of water vapour (go to www.esa.int/Our_Activities/Space_Science/Rosetta)
You can read the same story at http://phys.org/print323351635.html … where an ESA spokesman says, 'it does indicate the Sun starts to have a visible impact on comets even at a great distance …' and a NASA spokesman adds, 'we always knew we would see water vapour outassing from the comet but we were surprised at how early we detected it'.
The Rosetta spacecraft will come within 100km of the comet on August 6th and will accompany it as a consort for another 12 months. In NOvember it will despatch a 220 pound lander, the Philae, which will hook itself to the comet's surface and carry out a number of experiments. This is an exceptional project and a wonderful encounter – and no doubt the set up involved a lot of computer simulation. It just goes to show this part of modern science is a real benefit – and in this instance, a huge positive.