A researcher at the University of Nebraska-Lincoln has helped solve a longstanding mystery about the source of cosmic rays. The powerful particles were discovered about a century ago but it’s always been a puzzle where they originate.
UNL physicist Greg Snow first explains what they are: “Okay, so cosmic rays are high-energy particles that are flying around in outer space and they come from a number of different places.” Scientists know some of the particles come from our sun or exploding stars. But Snow and an international team of more than 350 scientists have been looking for the source of cosmic rays that carry the greatest amount of energy.
He says they’re all around us. “In fact, as you and I are sitting here talking, we have cosmic ray particles from outer space going through us all the time,” Snow says. “In five minutes, you’ll have a few thousand of these particles going through your body and you don’t know it.”
The group in Lincoln used particle detectors and computers to map where the highest-energy cosmic rays were originating. They pointed to galaxies with giant, turbulent black holes in the center.
Snow says the discovery gives us a better understanding of the science of cosmic rays – some of which helped make our world what it is: “There was a song by the singer Moby called ‘We are Made of Stars’ or something like that and that’s actually true,” Snow says. “All of the heavy elements that exist on Earth – like iron, aluminum, etcetera – all of those atoms are remnants of exploding stars that have exploded either in our galaxy or other galaxies.”
So we wouldn’t exist, Snow says, without ancient cosmic rays that helped bring about some of the Earth’s elements. The findings by Snow’s research team were published in the journal Science.