This artist's impression shows NASA's Cassini spacecraft exploring the magnetic environment of Saturn. Saturn's magnetosphere is depicted in grey, while the complex bow shock region — the shock wave in the solar wind that surrounds the magnetosphere — is shown in blue. The image is not to scale.  CREDIT: ESA Enlarge

NASA's Cassini spacecraft has spotted solar particles moving at incredible speeds near Saturn, giving scientists a rare up-close look at phenomena that occur during dramatic star explosions.

The particles flowed from the sun during a strong blast of solar wind, then plowed into Saturn's magnetic field shortly thereafter. This encounter, which Cassini observed in February 2007, created a shockwave that accelerated the particles to super-high energies, scientists said.

Similar shockwaves commonly form in the aftermath of massive star explosions called supernovas, ramping up nearby particles to nearly the speed of light. Researchers think supernova shockwaves are the primary source of cosmic rays, high-energy particles that pervade our Milky Way galaxy and slam into Earth's atmosphere continuously.

It can be tough to study distant supernovas and their shockwaves, so Cassini's observations provide a welcome proxy, scientists said.

"Cassini has essentially given us the capability of studying the nature of a supernova shock in situ in our own solar system, bridging the gap to distant high-energy astrophysical phenomena that are usually only studied remotely," Adam Masters, of the Institute of Space and Astronautical Science, Sagamihara, Japan, said in a statement.

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