September 7, 2013
Hunting Cosmic Rays
In an experiment, the impact of which would not be fully grasped for decades, the Austrian-American physicist Victor Hess launched a particle detector upon a balloon. Sending the experiment into the atmosphere he confirmed that very high energy charged particles — curiously called Cosmic Rays, which aren’t rays at all — are raining down on the Earth from the Universe around us.
Because these energetic particles carry a charge, ascertaining their origins has proven difficult. Magnetic fields that flow throughout our galaxy bend the path of the particles. So as we look up into the sky, they seem to come from all directions. So difficult was the task that it was more than a century after Hess’s historic balloon launch that scientists were able to gather the first conclusive evidence of their beginnings.
As part of my recent podcast series, I spoke with Stanford physicist Stephan Funk about the recent study he completed using the Fermi Gamma-ray Telescope. By looking for a very specific gamma-ray signature in supernovae spectra they were able to demonstrate that these violent explosions drive much of the cosmic ray flux we observe.
In part one of my interview with Dr. Funk he tells us the history and development of our understanding of cosmic rays. Then, we continued our conversation on part two, where he shares about his amazing discovery and the continuing work to understanding one of the great astronomical mysteries of the last century.
And be sure to check back to the podcast page, as in the next couple of days we’ll be releasing the final piece to the puzzle and talking about the Fermi Gamma-ray Telescope, one of NASA’s flagship instruments that is changing our very understanding of the Cosmos.
Image Credit: alevtina / Shutterstock