Earth is humanity’s cradle, but by no means can it completely harbour us from harm. Many risks threaten individual lives, but there are some catastrophic enough to wipe out entire species. Is it possible for the prolific human species to face extinction?The Sun provides all living things with the heat (and, indirectly, food) needed to survive. Yet for all its needed sustenance, there are also times when it turns against life, in particularly spectacular fashion. Every 13 years it throws a tantrum of sorts, with the next one due on late 2012.
