Smaller asteroid may have killed dinosaurs

HONOLULU, April 11 (UPI) -- A scientist in Hawaii says the asteroid implicated in the extinction of dinosaurs was much smaller than previously suggested.

Francois Paquay of the University of Hawaii Manoa has developed a new tool using variations of osmium isotope composition in the marine sediment record to estimate the size of asteroid impacts, the university said Thursday in a release.

The findings are published in the journal Science.

Paquay said sediment shows the asteroid that created Chicxulub crater off the coast of Mexico was about 2.5 miles wide -- less than half the size that researchers had previously suggested, the Los Angeles Times reported.

The researchers estimate the size of the asteroid that created the 63-mile-wide Popigai crater in Siberia at about 1.7 miles across. Previous estimates had put that asteroid at about 2.5 miles across.