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More Cosmic Rays

November 29, 2016

The Sun’s interactions with Earth are part sword, part shield. Outbursts from the Sun pelt our planet with radiation and charged particles. That can knock out satellites, damage power grids, and cause other problems.

On the other hand, the Sun shields Earth from cosmic rays — charged particles from exploding stars and other sources. These particles hit molecules in the upper atmosphere, creating showers of other particles that then hit the surface.

These particles may help trigger lightning, and may even play a role in cloud formation. Over the course of a year, they also contribute a bit more than one-tenth of the radiation dosage that most people receive from the natural environment. The levels are higher for airline pilots, who may receive half of their radiation from cosmic rays.

The level of cosmic rays varies, thanks largely to the Sun. Our star generates a strong magnetic field, which deflects many of the particles that make up cosmic rays. So without the Sun’s magnetic field, we’d all get zapped by more of them.

The Sun’s field is especially strong when the Sun belches out more of its own particles toward Earth. During those active periods, the number of incoming cosmic rays drops dramatically.

A few studies have even shown that the number of deaths caused by heart attacks goes down when solar activity goes up — suggesting that we need the solar shield to protect us from cosmic rays.

We’ll have more about cosmic rays tomorrow.

Script by Damond Benningfield

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