the volcano on la palma in the canary islands has erupted again this evening, just as it was thought that the worst was over, a significant amount of lava has again started moving down the volcano, destroying everything in its path. hundreds of homes have already been destroyed and thousands of people have been moved out since the first eruption over a week ago. for nearly half a century, satellites have been orbiting earth and providing a unique record of the evolving state of the planet. the latest satellite, called landsat 9, was launched this evening. nasa claims this newest addition to the longest continuous record of the earth s surface will enable scientists to separate the human and natural causes of environmental change, as our science editor david shukman explains. and lift off! a murky, rainy day in california, but that was not going to stop this vital launch from going ahead. rising into orbit, it is the latest in a long line of satellites,