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EARTH CHANGING SCIENCE
This week Science in Action reports from the 176th annual meeting of the American Association for the Advancement of Science. It was held in San Diego, California, and the theme was "Bridging Science and Society". Two sessions at the AAAS brought together climate scientists, geologists, and social policy scholars, to discuss geoengineering and how to use it to combat global warming - proposals include altering the atmosphere to make it reflect away more of the heat of the sun, or seeding clouds above the oceans. But it is a controversial subject. Professor Martin Bunzl, the Director of the Rutgers Initiative on Climate Change, Social Policy and Politics and first Professor Ken Caldeira at the Carnegie Institution at Stanford University have very different views. Jon Stewart caught up with them at the meeting.

CHEETAH CHAT
San Diego Zoo is known for its conservation work, with projects running in 35 different countries. Jon Stewart visited the Zoo's Wild Park to try and find out what some of the animals have to say. Scientists at the Zoo's Institute for Conservation Research have been recording cheetahs and elephants talking to each other and have found they have a quite a complex way of communicating. Matt Anderson the Acting Director of behavioural biology at the Institute showed Jon exactly what they have been doing.

HALF A CENTURY OF THE LASER
The AAAS Science Conference also celebrated the 50th anniversary of the invention of the laser. Today, lasers are a part of almost every aspect of our lives, from tiny ones in CD and DVD players, to huge ones that are being used to create a mini star here on Earth – with the promise of delivering clean energy. Jon Stewart speaks to Thomas Baer, the Executive Director of the Stanford University Photonics Research Centre, who talks about the history of the laser and how it's now being used in modern medicine and Edward Moses, the Director of the National Ignition Facility, which houses the world's largest and most energetic laser, explains how soon they may be able to create a miniature star in the laboratory.