Some 66 million years ago, an errant asteroid wiped out three-quarters of all plant and animal species on Earth, most notably taking down the dinosaurs. That has long been the scientific consensus. However, three years ago, Harvard astronomers offered an alternative hypothesis: The culprit may have been a fragment of a comet thrown off-course by Jupiter’s gravity and ripped apart by the Sun.

Now an international team of scientists have reaffirmed the original hypothesis, according to a new paper published in the journal Science. They analyzed ruthenium isotopes from the Chicxulub impact crater and concluded the impact was due to a carbonaceous-type asteroid, likely hailing from beyond Jupiter.