“From a geologic perspective, events like this have happened many times in the past. Asteroids the size of 1950 DA have probably struck the Earth about 600 times since the age of the dinosaurs,” researcher Steven Ward said.
Although the probability of an impact from 1950 DA is only about 0.3 percent, it is the only asteroid yet detected that scientists cannot entirely dismiss as a threat. A team of scientists led by researchers at NASA’s Jet Propulsion Laboratory reported on the probability of 1950 DA’s crossing paths with the Earth in the April 5, 2002, issue of the journal Science.
A NASA-led campaign to detect large asteroids in near-Earth orbits is about half way toward its goal of detecting 90 percent of those larger than 1 kilometer in diameter (the size of 1950 DA) by 2008. “Until we detect all the big ones and can predict their orbits, we could be struck without warning,” said astronomer Erik Asphaug. “With the ongoing search campaigns, we’ll probably be able to sound the ‘all clear’ by 2030 for 90 percent of the impacts that could trigger a global catastrophe.”