Dinosaur-killing Chicxulub asteroid formed in Solar System’s outer reaches

The asteroid that wiped out the dinosaurs was formed beyond the orbit of Jupiter. When the object struck what is now Chicxulub, Mexico 66 million years ago, the enormous explosion left a layer of asteroid material all over Earth. Researchers looked at an element preserved in that layer, ruthenium, and found that it matched the make-up of the type of asteroid that formed in the outer Solar System, rather than the type that was produced in the inner region.