Scientists scour the clouds for signs of life To search for bacteria and other microbes in clouds, the 200 feet long airship will carry equipment from Nasa that can detect life in it. Researchers at Nasa are working with British scientists in the hope of understanding more about the role such life may play in cloud formation. They believe they may even discover new species of microbes. Similar attempts to chart the microbial life in the oceans resulted in thousands of news species being discovered. Felicity Aston, the lead meteorologist on the expedition and a former researcher at the British Antarctic Survey, said: "One of the holes in our knowledge about clouds is exactly how a cloud droplet grows and what makes it fall out the sky. It is really interesting to look not only at how life is affected by weather but how weather is affected by life - what role do these organisms play in cloud formation. Scientists at Nasa and Georgia Institute of Technology earlier this year published new findings that showed vast populations of microbes are living between four and six miles above our heads. Air samples taken from the upper troposphere by an aircraft revealed 314 different types of bacterial in the air above the Atlantic Ocean and the US. Bacteria accounted for around 20 per cent of the particles collected in the air samples. Jonathan Renouf/BBC It is believed that these bacteria may catalyse ice crystal formation, leading to water to condense around them to produce clouds. Scientists from the University of Oregon, working under Dr Jessica Green, have also been taking samples from the atmosphere to look for signs of life. They have just returned from Mount Bachelor in Oregon where they took air samples the summit of Mount Bachelor at around 9,000 feet. They are also in talks to use the Red Bull Stratos Balloon to take samples from around 18 miles up in the atmosphere. Researchers on Cloud Lab hope to explore further how bacteria are distributed through the atmosphere. Andy Torbert, a former paratrooper, is due to make a high altitude parachute jump to collect samples of the atmosphere from 25,000 feet - more than four miles up. These will allow scientists to see how the microbes higher in the atmosphere vary compared to those closer to the ground. The researchers also hope to explore what other particulates form in the atmosphere while also gathering data on the formation of hurricanes off the coast of Florida. The Skyship 600 airship they will be travelling in will fly across the US, over the Rockie Mountains and end the expedition in Big Sur, California. Jonathan Renouf, BBC executive producer on the project, said: "The bacteria story is one of the most exciting research that is going on in this area. But we will also be looking at weather and air movements. We tend to think of ourselves as living on the surface of the planet, but we also live on the bottom of an ocean of air. That ocean of air can be a very turbulent and violent place, so we will be monitoring the parameters hurricanes from the airship. Perhaps the biggest challenge will be getting over the Rockies as it will be very weather dependent.