Space
Scientists Crack Mystery Surrounding the Origin of Cosmic Rays
Staff Reporter
First Posted: Feb 16, 2013 01:52 AM EST
Scientists at Fermi Lab in Chicago have cracked a long cosmological mystery: where do cosmic rays come from?
There is now conclusive proof that this question has been answered once and for all. Many cosmic rays raining down on Earth come from distant exploded stars. Thanks to our atmosphere and Earth’s magnetic field we’re protected from the deadly intensity of these cosmic rays, which are mostly ultra-fast proton particles and would threaten life on Earth if not deflected.
Nasa's Fermi telescope was used to analyze the very distinctive light that is produced when these protons crash into other particles in space.
This allowed scientists to trace their source directly to ancient supernovas.
The study was led by Stefan Funk from Stanford University and the SLAC National Accelerator Laboratory.
His team has published its work in this week’s Science magazine. Dr Funk himself has also presented it here in Boston at the annual meeting of the American Association for the Advancement of Science.
Scientists have long suspected that many of the cosmic rays detected at Earth were accelerated in the colossal blasts that mark the demise of big stars, but the evidence has always carried some ambiguity.
Part of the reason is the protons’ positive charge. This means they get deflected by any magnetic field they encounter as they travel through space, making it impossible with complete confidence to track them back to the place they set off.
"When they arrive at Earth, they arrive as we say isotropically - that is, with the same flux from all directions," Dr Funk told the BBC.
"So if we had cosmic ray eyes and were to look at the sky, it would be extremely boring because it would just be a plane that appears the same in every direction."
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First Posted: Feb 16, 2013 01:52 AM EST
Scientists at Fermi Lab in Chicago have cracked a long cosmological mystery: where do cosmic rays come from?
There is now conclusive proof that this question has been answered once and for all. Many cosmic rays raining down on Earth come from distant exploded stars. Thanks to our atmosphere and Earth’s magnetic field we’re protected from the deadly intensity of these cosmic rays, which are mostly ultra-fast proton particles and would threaten life on Earth if not deflected.
Nasa's Fermi telescope was used to analyze the very distinctive light that is produced when these protons crash into other particles in space.
This allowed scientists to trace their source directly to ancient supernovas.
The study was led by Stefan Funk from Stanford University and the SLAC National Accelerator Laboratory.
His team has published its work in this week’s Science magazine. Dr Funk himself has also presented it here in Boston at the annual meeting of the American Association for the Advancement of Science.
Scientists have long suspected that many of the cosmic rays detected at Earth were accelerated in the colossal blasts that mark the demise of big stars, but the evidence has always carried some ambiguity.
Part of the reason is the protons’ positive charge. This means they get deflected by any magnetic field they encounter as they travel through space, making it impossible with complete confidence to track them back to the place they set off.
"When they arrive at Earth, they arrive as we say isotropically - that is, with the same flux from all directions," Dr Funk told the BBC.
"So if we had cosmic ray eyes and were to look at the sky, it would be extremely boring because it would just be a plane that appears the same in every direction."
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone