Cosmic accelerators discovered in our galaxy by UCLA physicists, Japanese colleague

Physicists from UCLA and Japan have discovered evidence of "natural nuclear accelerators" at work in our Milky Way galaxy, based on an analysis of data from the world's largest cosmic ray detector.

Cosmic rays of the highest energies were believed by physicists to come from remote galaxies containing enormous black holes capable of consuming stars and accelerating protons at energies comparable to that of a bullet shot from a rifle. These protons — referred to individually as "cosmic rays" — travel through space and eventually enter our galaxy.

But earlier this year, physicists using the Pierre Auger Observatory in Argentina, the world's largest cosmic ray observatory, published a surprising discovery: Many of the energetic cosmic rays found in the Milky Way are not actually protons but nuclei — and the higher the energy, the greater the nuclei-to-proton ratio.

"This finding was totally unexpected because the nuclei, more fragile than protons, tend to disintegrate into protons on their long journey through space," said Alexander Kusenko, UCLA professor of physics and astronomy and co-author of the Physical Review Letters research. "Moreover, it is very unlikely that a cosmic accelerator of any kind would accelerate nuclei better than protons at these high energies."

The resolution to the paradox of the nuclei's origin comes from an analysis by Kusenko; Antoine Calvez, a UCLA graduate student of physics who is part of Kusenko's research group; and Shigehiro Nagataki, an associate professor of physics at Japan's Kyoto University. They found that stellar explosions in our own galaxy can accelerate both protons and nuclei. But while the protons promptly leave the galaxy, the heavier and less mobile nuclei become trapped in the turbulent magnetic field and linger longer.

"Cosmic rays are high energy charged particles, originating in outer space, that travel at nearly the speed of light and strike the Earth from all directions. Most cosmic rays are the nuclei of atoms, ranging from the lightest to the heaviest elements in the periodic table. Cosmic rays also include high energy electrons, positrons, and other subatomic particles. The term "cosmic rays" usually refers to galactic cosmic rays, which originate in sources outside the solar system, distributed throughout our Milky Way galaxy. However, this term has also come to include other classes of energetic particles in space, including nuclei and electrons accelerated in association with energetic events on the Sun (called solar energetic particles), and particles accelerated in interplanetary space." http://www.srl.caltech.edu/personnel/dick/cos_encyc.html Cosmic rays may broadly be divided into two categories, primary and secondary. The cosmic rays that arise in extrasolar astrophysical sources are primary cosmic rays; these primary cosmic rays can interact with interstellar matter to create secondary cosmic rays. The sun also emits low energy cosmic rays associated with solar flares. The exact composition of primary cosmic rays, outside the Earth's atmosphere, is dependent on which part of the energy spectrum is observed. However, in general, almost 90% of all the incoming cosmic rays are protons, about 9% are helium nuclei (alpha particles) and nearly 1% are electrons. The ratio of hydrogen to helium nuclei (28% helium by mass) is about the same as the primordial elemental abundance ratio of these elements (24% by mass He) in the universe. The remaining fraction is made up of the other heavier nuclei which are abundant end products of stars' nuclear synthesis. Secondary cosmic rays consist of the other nuclei which are not abundant nuclear synthesis end products, or products of the Big Bang, primarily lithium, beryllium, and boron. These light nuclei appear in cosmic rays in much greater abundance (about 1:100 particles) than in solar atmospheres, where their abundance is about 10−7 that of helium. http://en.wikipedia.org/wiki/Cosmic_ray __________________________________________________________________________________________________________________________________________________ Man! After all these years I still can't get a straight answer!

Weight of a Proton: 1.6726 X 10-27 kg

Weight of a Remington .223 caliber bullet 0.00356394 kg

Given the difference in weights I find the statement in the article to unimaginable.

Given the difference in weights I find the statement in the article to unimaginable.

I hear you. A single proton can have the kinetic energy of the asteroid that wiped out the dinosaurs. And much more than that if you push it close enough to the speed of light.

Relativistic kinetic energy is given by:

In fact, as you can see, E_k approaches infinity as v --> c, which is one of the reasons c is the absolute speed limit for objects with mass moving through space.

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