The biggest 4th July explosion ever?

 作者:都薷     |      日期:2019-02-27 06:11:03
NASA has gone a long way to guarantee Americans some cosmic fireworks for this year’s Independence Day: 430 million kilometres to be precise. That’s how far the Deep Impact spacecraft will have travelled since leaving Earth five months ago to rendezvous with Comet Tempel 1 on 4 July. The craft is right on track to fire a 370-kilogram chunk of copper at the comet, and to analyse the ensuing plume of gas and dust from the collision,