Computational creativity and the future of AI

NASA confirms the origin of cosmic rays


February 20, 2013

A multiwavelength composite image of supernova remnant IC 443, known as the Jellyfish Nebu...

A multiwavelength composite image of supernova remnant IC 443, known as the Jellyfish Nebula

Image Gallery (4 images)

The study of data collected by NASA's Fermi Gamma-ray Space Telescope has revealed that cosmic rays, some of the fastest traveling particles in the universe, are produced by supernovae. A separate study by the European Southern Observatory (ESO) has made similar findings, largely corroborating the Fermi results.

Cosmic rays are subatomic particles, made up of around ninety percent protons, that move through space at close to the speed of light. Magnetic fields deflect and distort the path of the particles, making it near impossible to determine their point of origin. However, the presence of cosmic rays can, under certain circumstances, lead to the emission of gamma rays, a form of light that travels to us directly from its source.

NASA's Fermi Large Area Telescope (LAT) has been observing these gamma rays since its launch in 2008, focusing on two supernova remnants known as IC443 and W44. Both of these are expanding into clouds of interstellar dust which emit gamma-rays when hit by high-speed particles from the supernova remnants.

The W44 supernova remnant
The W44 supernova remnant

After analyzing four years' worth of data, the team has managed to identify a feature in the gamma rays of both IC443 and W44, which is claimed to constitute conclusive proof that supernova remnants accelerate cosmic rays. The scientists identified the presence of particles known as neutral pions, which are created in collisions between cosmic rays and normal protons. These neutral pions break down into pairs of gamma rays and exhibit specific and identifiable characteristics.

Stefan Funk of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University said that "the discovery is the smoking gun that these two supernova remnants are producing accelerated protons."

The thousand-year-old SN1006 supernova remnant
The thousand-year-old SN1006 supernova remnant

An ESO study, released simultaneously to the Fermi findings, largely corroborated the discovery. The ESO team used its Very Large Telescope (VLT) to observe a supernova site known as SN 1006, focusing on the “shock front” where high-speed materials ejected by the supernova interact with stationary interstellar matter.

While the team was unable to confirm the existence of cosmic rays, a number of “seed particles” were identified. These particles go on to interact with other materials, eventually reaching the extremely high energy levels associated with cosmic rays.

Sources: NASA, ESO

About the Author
Chris Wood Chris specializes in mobile technology for Gizmag, but also likes to dabble in the latest gaming gadgets. He has a degree in Politics and Ancient History from the University of Exeter, and lives in Gloucestershire, UK. In his spare time you might find him playing music, following a variety of sports or binge watching Game of Thrones.   All articles by Chris Wood
Post a Comment

Login with your gizmag account:

Or Login with Facebook:

Related Articles
Looking for something? Search our 31,282 articles
Recent popular articles in Space
Product Comparisons