spacetoday.net: Dust grains returns by NASA mission have interstellar origins

Posted: Fri, Aug 15, 2014, 8:51 AM ET (1251 GMT)
Stardust spacecraft illustration (NASA/JPL)

Scientists reported this week that several dust grains returned by a NASA mission eight years ago likely originated from outside the solar system. In a paper published in the journal Science, researchers said they identified seven dust grains brought back to Earth by the Stardust mission that appear to have originated from beyond the solar system. That assessment is based on the trajectories of the particles, in line with the flow of the interstellar wind and separate from cometary dust also sampled by the spacecraft. Analysis of those dust grains indicates their composition is more diverse than originally thought. Scientists think the largest particles may have originated in the protoplanetary disks surrounding other stars. Researchers found the interstellar dist grains through the use of a citizen science project where people looked at images of collector plates from the spacecraft to identify tracks created by particles.