The killer-asteroid movies are almost forgotten, but the threat is real and unquantified. Will it fall to hobbyists to save the world?
Its name is 1950DA, it's the size of a small mountain, and it's headed for Earth. According to one grim scenario, 1950DA will hit its target-most likely water, since there is more water than land on our planet-and plunge to the seabed in a fraction of a second. When the asteroid meets the ocean floor, it will explode, excavating a crater 11 miles wide.
A column of water and debris will shoot a few miles into the sky-to the height of a low-flying jetliner. Then skyscraper-high walls of water will head for shore, eventually breaking in the shallows