美国国家航空和宇宙航行局(NASA)航天飞机雷达地形测量任务公布的一幅高清晰度的照片,为确定地球曾经遭受一颗巨大的彗星或小行星的撞击提供了有形的证据。这次撞击在地面形成一个180千米宽、900米深的弹坑,那是地球有史以来最糟糕的一天。这个被称做“希克苏鲁伯”(Chicxulub)的大陨石坑从1980年以来一直吸引着科学家的注意。1990年,根据人造卫星的数据和地面的研究,大部分科学家认定这个陨石坑的形成大约是在6500万年前,并导致恐龙和地球 A high-resolution photograph published by NASA’s space shuttle radar topographic mission provided tangible evidence that the Earth was once hit by a giant comet or asteroid. The impact created a crater of 180 kilometers in width and 900 meters deep on the ground, the worst day ever in Earth’s history. The giant crater, known as Chicxulub, has drawn the attention of scientists since 1980. In 1990, most scientists, based on data from satellites and terrestrial studies, determined that the crater was formed about 65 million years ago and led to dinosaurs and earth