But hundreds of millions are still vulnerable. if the virus spreads rapidly in any country, it can mutate further. that puts the whole world at threat. yogita limaye, bbc news, india. now, you might have thought that the hottest place in the solar system is the sun. well, not any more, it's actually on an industrial estate in the south of england. or at least it is every time a nuclearfusion reactor there is fired up. fusion reactions power the sun and scientists have been trying for decades to recreate them here on earth to try to generate low carbon electricity. our climate editor justin row...