Today is the day that NASA expects a spacecraft named DART should hit an asteroid millions of miles away, on purpose. A news release from NASA, says DART will hit it at a speed of about 22,500 km/h, which it expects should be enough to nudge the asteroid into a slightly different trajectory.

The reason for this experiment is it could demonstrate that if a killer asteroid were ever to be heading towards Earth, there may be a chance of diverting it. NASA program scientist Tom Statler says, “This is stuff of science-fiction books and really corny episodes of Star Trek from when I was a kid, and now it’s real.” Scientists will be watching the crash, but it will take days or even weeks to find out if it actually changed the orbit.