[Lee Stewart]

While NASA is in fact working on ways to destroy or deflect an incoming asteroid, it's possible that blowing one up would just shatter it into pieces that could still damage Earth. Even worse, a recent study shows the asteroid's own gravity could help it re-form. But if scientists don't get enough warning, a “robust disruption and dispersal of the fragments may be the only viable option to prevent the impact,” says Megan Bruck Syal, a planetary defense researcher at the Lawrence Livermore National Laboratory.