Because they’ve smashed into every planet in the solar system, including Earth, and one good hit could mean game over for life here. Asteroids travel at tens of thousands of miles an hour – speeds that transfer into destructive energy when they collide with a planet, moon, or each other. An asteroid 450 feet (137 m) across could destroy an entire city. More than a thousand people were injured in 2013 when an asteroid just 62 feet (19 m) wide exploded high in the atmosphere above Chelyabinsk, Russia. An asteroid impact 65 million years ago may have wiped out the dinosaurs.
Picture Credit : Google