NASA Spacecraft Finds Source Of Cosmic Space Radiation

Cosmic rays are most likely to be relatively recent radiations from clusters of stars near us, according to scientists.

Such rays are high-speed atomic nuclei who have a wide range of energy, the most powerful ones racing at a high speed of light.  While the earth's atmosphere protects the earth from these rays, they can be hazardous to astronauts that journey through space. They can also be harmful to scientists venturing into space, such as Mars mission astronauts.

Such rays have been created by many violent events occurring in space. These may be explosive events such as solar flares and coronal mass ejections on the sun, or massive black holes at the centers of other galaxies.

Researchers relied on the effects of NASA's Advanced Composition Explorer (ACE) spacecraft, which enabled researchers to assess the age of the cosmic rays, and also the distance from their source.

"Our detection of radioactive cosmic-ray iron nuclei is a smoking gun indicating that there has likely been more than one supernova in the last few million years in our neighborhood of the galaxy," said  Robert Binns of Washington University and lead author of the study.

Eric Christian of NASA's Goddard Flight Space Center explained that ACE identified almost 300,000 galactic cosmic rays of ordinary iron, but only 15 of radioactive Iron-60. The very existence of Iron-60 indicates that the cosmic rays were made just recently, he said. They were probably created by clusters of massive stars within a few light years in our galaxy.

NASA's ACE program can be viewed more extensively here.