A total solar eclipse will today speed across the southern hemisphere. The shadow of the moon will first darken the south Atlantic about 250 miles east of the Uruguay coast, cross the Atlantic and then vanish into darkness as the night falls over the Indian Ocean. As with the eclipse that swept across Europe and the south coast of Britain two years ago, there is one group of people who will be watching the event extremely closely. A solar eclipse provides scientists with a unique view of the sun's corona. As well as other science news, GeoffWatts talks to some of the scientists hoping to make use of the precious few minutes of visibility the eclipse will give them. Producer Alexandra Feachem