The University of Massachusetts geoscientist Stephen Haggerty contends that some of the carbon in diamonds comes from outer space.

Haggerty argues against the long-held view that the carbon in diamond comes from the remains of plants and marine organisms as they decayed under the high temperatures and pressures of the Earth’s deep interior. The invited review is titled, "A Diamond Trilogy: Superplumes, Supercontinents, and Supernovae."

Many in the scientific community have long theorized that diamonds are primarily the result of organic materials that were dragged into the Earth’s interior as one continental plate was thrust beneath another in a process called subduction. This theory holds that the organic material, when exposed to the extreme heat and pressure within the Earth for millions of years, produced the carbon in diamonds. But the fossil record, and the dating of diamonds, indicate that this carbon is at least...