蜜芽传媒

How do you protect Earth from a killer asteroid? Nasa is about to find out by smashing a spacecraft into one. The thinking is you would only need to change the rock's velocity by a small amount to alter its path so that it misses Earth - provided you do it far enough in advance.

The Double Asteroid Redirection Test (Dart) mission will check out this theory with a near-head-on crash into 160m-wide Dimorphos at over 20,000km/h. This should change its orbit around a much larger asteroid, called Didymos, by just a few minutes every day.

Dr Andy Rivkin is the lead investigator on the Dart Mission. He told Newsday: 鈥淩ight now the tools we have to divert an asteroid鈥�comes down to the sort of thing you might see in a movie where you would take a nuclear package鈥�and detonate it and鈥�use the shock wave to change its orbit so that it doesn鈥檛 intersect the earth鈥檚 orbit. Nuclear devices are not the sort of thing you want to have as your only plan鈥�we鈥檙e all feeling very good about the odds that we鈥檙e going to succeed.鈥�

(Picture: Handout image of Nasa鈥檚 Double Asteroid Redirection Test or Dart. A spacecraft built by Nasa is set to intentionally crash into a small asteroid as part of a planetary protection test mission. Credit: Nasa/PA Wire.)

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