CONTRAILS - THE white streaks left by aeroplanes crossing the sky - will contribute significantly to global warming within the next 50 years, according to American and German researchers. Though the ice clouds (created when jet engines release water vapour) are short-lived in dry air, they can last for hours in moist air, looking like high-level cirrus clouds. Impact will increase with rises in the volume of air traffic: clouds trap heat in the atmosphere and prevent it escaping to space. By 2050, said Patrick Minnis of Nasa, in areas of Europe with the heaviest air traffic, contrails could cover up to 4.6 per cent of the sky.
THE INTERNATIONAL Space Station had a close encounter with a piece of space junk last week, made worse by the failure of ground controllers to move the station out of the way: the Russian computers on board the uncrewed station refused to fire for as long as the controllers demanded, and shut the station down instead. Though the debris only had a 1 per cent chance of hitting the station, that could have destroyed it. The two missed each other by seven kilometres.
THE US Patent and Trademark Office has ruled that you cannot patent human- animal "chimeras" made from a mixture of the two's cells. The decision followed a test case submitted by Jeremy Rifkin, who was seeking either to provoke a ban or to prevent commercial companies from producing such hybrids by getting the patent himself and restricting its use. The USPTO rejected the claim because it "embraces a human being" - which is not allowed because it could be seen as breaking the law banning slavery. But Rifkin is pursuing the case by appealing, because he thinks that recent applications on cloned cells (including human cell DNA transplanted into denucleated cows' eggs) come under the same definition, and so should also be outlawed.