A Japanese spacecraft will fire a bullet into an asteroid on Thursday. Here's why.
A Japanese spacecraft is set to touch down on a distant asteroid Thursday, before shooting a bullet into the space rock to capture a bit of debris that eventually will be returned to Earth. Launched in 2014 by the Japan Aerospace Exploration Agency (JAXA), the Hayabusa 2 probe reached asteroid Ryugu in June 2018, after a voyage of 2 billion miles. In the months since then, the refrigerator-sized craft dropped a pair of small rovers on the space rock and has been inching ever closer to its surface. If all goes according to plan...