The scenario in which an asteroid or a comet hit the Earth and destroys civilization, and much of the life on the planet, has been the stuff of scientific nightmares as well as science fiction drama. Several past asteroid impacts suggest that Earth changing events have already occurred and will likely happen again unless they are stopped. NASA is setting about testing one way to ward off an asteroid impact.
DART to be launched against an asteroid
NASA has decided to move from concept development to the preliminary design phase a mission called the Double Asteroid Redirection Test or Dart.
DART is not yet a budget item on NASA’s manifest, but it would need to be funded and approached for a 2022 launch. At that time, in October 2022, a double body asteroid called Didymos consisting of Didymos A, a rock a half a mile in diameter, and Didymos B, 530 feet in diameter asteroid orbiting its larger companion, will approach the Earth.
The idea is to send DART against Didymos B and strike it dead center. Then scientists will measure how much its orbit has been altered. The mission would test the strategy of kinetic impact for asteroid defense. If an asteroid is detected coming at Earth far away enough, a kinetic impactor could be sent to alter its trajectory just enough to cause it to miss our world entirely.
Didymos, by the way, will also approach the Earth in 2024.
Past asteroid impacts
The classic example of an asteroid impact that changed the history of the Earth is the one that hit the vicinity of the Yucatan 65 million years ago, which caused a heat and shock wave followed by a nuclear winter sufficient enough to kill the dinosaurs.
The Tunguska Event in 1908 resulted from an asteroid that exploded in the air above Siberia with the power of a massive nuclear bomb, flattening 770 square miles of forest. Had the asteroid exploded over a city, say Moscow, it would have destroyed it. In 2013, the Chelyabinsk meteor, a 25-meter rock, burst apart in the skies over the southern region of the Ural Mountains, breaking windows and causing numerous injuries, but fortunately there were no deaths.
Defense against rocks coming from the skies
The study of small bodies and their potential effects on the planet is, perhaps, one of the more unsung but very crucial functions that NASA has undertaken. It is not a case of if but when the Earth will be threatened by a rock coming from the sky. Experiments like DART will be crucial for making sure that humanity does not suffer the fate of the dinosaurs.
