Our cosmic ray connection – Part 2
It’s not just through mutations though, that cosmic rays influence life on Earth. Some studies link periodic Ice Ages to variations in the flux of galactic particles, hitting the atmosphere.
Also, Jasper Kirkby, a scientist at CERN (Europe’s high-energy research centre), argues that cosmic rays may contribute to cloud formation and, consequently, could be a factor in climate change.
Not incidentally, cosmic rays have endowed science, with an invaluable research tool. When primary particles strike molecules of atmospheric nitrogen, they create neutrons that cause carbon-14 to form.
Plants incorporate this radioactive carbon isotope into their system. The vegetation is, in turn, ingested as animal nutrient.
Carbon-14 decays at a constant rate, which enables scientists to date organic material, as far back as 50,000 years.
If you fly a lot, or live in the mountains, cosmic ray exposure is greater. This raises the cancer risk, slightly—but not enough to worry about.
Even so, NASA’s “Ask Us” blog advises pregnant passengers, to “fly low-latitude routes…That way, they are much-better protected by the Earth’s magnetic field”.
Lithium, third on the periodic table of chemical elements, plays an important role, both in our bodies and in industry.
It affects mental processes, plus the immune system, sodium transport and serotonin transmission. Lithium is also a critical component of cellular phones and rechargeable torchlight batteries.
Astronomers believe we can attribute the availability of terrestrial lithium, partly to cosmic ray collisions, at the edge of the Galaxy.
According to NASA, primary particles have a habit of bumping into things, no matter where they are– creating new elements, in the process.
In addition to most hydrogen and helium in the universe, it notes, some heavier elements were synthesized as well, after the formative Big Bang explosion, 13.8 billion years ago.
But this cannot account for the calculated abundance of lithium, beryllium and boron. “As it turns out,” says NASA’s posting, “some of the heavy elements… are produced from cosmic ray interactions”.
Presently, the consensus is that shock waves from the explosion of big stars (“supernovae” explosions) accelerate atoms to relativistic velocities (approaching the speed of light).
These zooming atomic pellets then collide with hydrogen and other atoms. The cosmic shrapnel thus produced, becomes new elements.
NASA cites the carbon nucleus as a case in point: “Eventually, it collides with a hydrogen atom in open space… [This] fragments the carbon nucleus…, [creating] two new particles–helium and lithium”.
Current theory ascribe cosmic ray origins to three main sources. Solar energetic particles (SEPs) stream from the Sun during flare eruptions. But these, NASA says, have relatively low energies.
The main source, it seems, is supernovae explosions, within our star system, the Milky Way. Seeking to confirm this, a researcher at Stanford University (U.S.A.), studied certain peculiar gamma ray flashes.
Speaking to BBC’s Jonathan Amos, Stefan Funk said these types of gamma rays are sparked from collisions between cosmic rays and slower-moving protons, in the gas and dust around a supernova.
Whereas cosmic rays can mess around in galactic magnetic fields for a million years, and arrive from any direction, Gamma ray photons come straight to us—pinpointing the galactic particle accelerator.
Astronomers at Germany’s prestigious Karlsruhe Institute of Technology announced, in 2013, that they had identified a third source, beyond our galaxy.
The lightest and most energetic particles, they found, are either accelerated inside another galaxy, or somewhere in intergalactic space.
A few of these particles doubtless penetrate our atmosphere, as muons do: Carrying information and physical influence that connect us to the remotest reaches of the universe.