获取独家产品信息，尽享促销优惠！立即订阅，不容错过
* 限···时··优惠
NASA X-ray spacecraft discovers supernova wreckage at the heart of the Milky Way
NASA's Chandra X-ray spacecraft has detected the supernova wreckage of a dead star that erupted 1,700 years ago and ejected debris at 2 million miles per hour.
