Solving The Mystery Of The Origin Of Cosmic Rays – With Special Guest Dr. Stefan Funk

August 30, 2013

John P. Millis, PhD for – Your Universe Online

Streaming all across the Universe, very high-energy charged particles move like rivers through our galaxy. Eventually, they can impact our atmosphere, setting in motion a cascade of particles and radiation that burrows through our gaseous canopy down to the surface of our tiny planet.

Attempts to understand the origins of these so-called cosmic rays are woven into the story of astronomy for the last hundred years. But it is not until now that we finally have data that may bring the mystery of cosmic rays to a close.

To tell us about this recent discovery, I was joined once again by Stanford Physicist Stephan Funk, one of the lead scientists on this important discovery. In this installment of redOrbit’s Your Universe Today podcast series, Dr. Funk discusses the latest theories about these cosmic rays, why this work has been so challenging, and finally how we were finally able to definitively resolve the matter of their origin.


After receiving his PhD from the Max Planck-Institut fuer Kernphysik and Heidelberg Universitaet, Germany, in 2005, Dr. Funk continued his work on cosmic rays and high-energy astrophysics at the Max Plank Institute, and then later at the Stanford Linear Accelerator and Collider (SLAC). Currently he serves as a professor of physics at Stanford.

Professor Funk’s research focuses on high-energy astrophysics to investigate how particles are accelerated in violent astrophysical sources such as supernova remnants or pulsar wind nebulae. Charged particles arrive at Earth ubiquitously but uniformly from all directions because they are deflected in interstellar and intergalactic magnetic fields. By using gamma-rays – photons a billion times more energetic than visible light – and electrically neutral (and therefore not deflected by magnetic fields), it is possible to test current understanding of the acceleration of charged particles such as protons or electrons in the most energetic objects in our universe.

Professor Funk’s research utilizes data from satellite missions such as the Fermi-LAT instrument as well as from ground-based Cherenkov telescopes, such as the H.E.S.S. telescope system in southern Africa and the planned CTA array.