Comet found to contain particles from inner solar system

Donald Brownlee / Nasa A 3-D picture shows Comet Wild 2 jutting out toward the observer. Looking at the image through red-blue glasses produces the 3-D effect.

Comet observations upend scientists’ beliefs

Dust samples show a mix of materials from distant reaches of solar system

By Alicia Chang

Updated: 11:10 a.m. PT Dec 14, 2006

Detailed observations from the first comet samples returned to Earth are debunking some of science’s long-held beliefs on how the icy, celestial bodies form.

Scientists expected the minute grains retrieved from a comet Wild 2 to be made up mostly of interstellar dust — tiny particles that flow through the solar system thought to be from ancient stars that exploded and died.

Instead, they found an unusual mix of primordial material as if the solar system had turned itself inside out. Hot particles from the inner solar system migrated out to the cold, outer fringes beyond Pluto where they intermingled and congealed to form a comet.

Science

Shown is a collection of comet dust trails retrieved from a capsule that returned to Earth last January. Scientists found an unusual mix of primordial material as if the solar system had turned itself inside out.

Many of the grains contained high-temperature minerals that likely formed in the hottest part of the solar nebula. At least one grain was made of a rare mineral seen in some meteorites, which are among the oldest samples in the solar system.