摘要
纵观人类历史,工程科学技术推动了人类经济社会和人类文明的快速发展。21世纪,为了维护安全,提高生活质量,建设更美好的、可持续发展的未来,人类必须应对和解决粮食不足、资源短缺、能源紧张、环境污染、气候异常、人口膨胀、区域贫困、疾病流行和经济危机等一系列重大挑战。2008年,美国国家工程院提出了21世纪人类需要应对的14项重大工程科技挑战。2013年和2015年,美国国家工程院。
On February 11, 2016, the Laser lnterferometer Gravitational- Wave Observatory （HGO） announced that on September 14, 2015 it had observed gravitational waves produced a billion light-years ago when two black holes collapsed into one another. This observation confirmed the prediction of Einstein＇s General Theory of Relativity that ripples in the fabric of space-time would generate gravitational waves. Ripples of a sufficient scale to observe would be caused by stupendously energetic events, such as the collision of neutron stars or the collapsing to^ether of two black holes.
