For a hundred years, scientists looked for the answer to a perplexing question. In 1859 British astronomers observed what we now call a solar flare. The next day there was a disturbance of Earth’s magnetic field called a geomagnetic storm. Scientists were puzzled over what was happening. After a century of study, the answer came down to solar wind and Earth’s magnetic shield.
In 1958, American astrophysicist Eugene Parker described the phenomenon and named it “solar wind.” The solar wind consists of charged particles ejected from the corona (extended outer layer) of the Sun and traveling at high speed into space. This material is plasma, a mixture of negative electrons and positive ions. Since electric charges and magnetic fields interact, the planet’s magnetic field steers the solar wind away from the planet’s surface when it reaches Earth. Because Earth’s magnetic field originates from the North and South poles, we see the interaction in those regions as beautiful auroras, the Northern and Southern lights.
What if Earth did not have a magnetic field? The solar wind would reach Earth’s surface and significantly damage living cells, bringing an end to life. Our neighboring planets Venus, Mars, and Mercury have little or no magnetic field and therefore are bombarded by the solar wind.
Why is our planet different? Why do we have the protection of a magnetic field? The motion of the molten iron in Earth’s core produces the magnetic field. Why does Earth have a molten iron core? Heat generated by the decay of the radioactive elements uranium and thorium keeps the iron core from becoming solid.
The bottom line is this: Hidden inside our planet is a magnetic-field generator powered by unseen radioactivity that gives us an invisible magnetic shield protecting us from invisible destructive particles coming from the Sun. This same process also gives us beautiful auroras we enjoy watching. The solar wind and Earth’s magnetic shield give us one more example of the beautiful design of the planet we call home. Did this all happen by accident? We don’t think so.
— Roland Earnst © 2021