Source: The Economist:
WORRYING about the threats posed by space rocks has traditionally been the preserve of the paranoid. No one doubts that asteroids have hit Earth in the past, with nasty consequences, but because the chances of any such event happening in a given year are so low, most people have been content to ignore the risk.
Today, however, a meteor was seen streaking through the sky above Yekaterinberg in Russia. It hit the ground (possibly landing in a lake) near another city, Chelyablinsk. It is thought to be the biggest meteor to hit Earth in more than a century. The shock wave it caused as it passed overhead blew out windows and injured hundreds of people. Also today, a 50 metre-wide asteroid called 2012 DA14 is zipping past Earth inside the orbit of some man-made satellites, marking the closest shave on record for an asteroid of that size.
This pair of unrelated events ought to focus minds, and not just among the small group of astronomers who have been worrying about asteroid strikes for many years. The first line of defence, as always, is knowing your enemy. To that end NASA, America’s space agency, has been watching the sky since 1998, trying to detect any chunks of rock whose orbits bring them close to Earth. These rocks are known as near-Earth objects (NEOs).
Categories: Americas, Science, Science and Technology, Space Exploration, Technology