Is the Earth being bombarded by strangelets? Some physicists believe that the Earth is being bombarded by "strangelets", which are "tiny cosmic missiles weighing tons and travelling at 900,000 mph. They are only the size of a pollen grain but so dense they can rip through the planet and exit on the other side in seconds." Two explosions in 1993 are felt to be caused by these strangelet impacts. (Via Slashdot.)