A Narrow Escape

Ninety-three million miles away, the sun shines brilliantly. Every second, hundreds of millions of tons of hydrogen are burned in its thermonuclear furnace, creating the light and heat we need to live. But the sun not only gives us life, it also threatens us with death. Storms that rage in the atmosphere send streams of electrons and protons -- the solar wind -- into space at over a million miles an hour. Occasionally great flares of these particles erupt from the turbulent atmosphere of the sun.

This lethal stream passes sun-scorched Mercury in about a day. About a day later, it passes cloud-covered Venus. Then it heads for a deadly encounter with Earth. If we were exposed to this stream of electrons, we would die instantly, as if struck by a lightening bolt.

But, as everyone who has used a compass knows, the earth is surrounded by a magnetic field. Scant minutes before this deadly stream could touch the earth, just fifty thousand miles over our heads, it is diverted by the magnetic field of the earth. Most of the stream passes us by, but a small part remains behind, resting over the north and south magnetic poles of the earth.

Then, as more and more of these electrons pile up above the poles, more than the magnetic field can support, a flow of electrons comes cascading down to earth. Just as a stream of electricity passing through a fluorescent tube lights it, this stream of electrons passing through our atmosphere cause the atoms there to emit light -- the Northern Lights.

Since all this is happening by the poles, the further north we go, the more likely we are to see these lights. In fact, in Barrow, Alaska, the northernmost town in the United States, they can see these lights almost every night. But wait. There's a price to pay for living so far north. Starting in mid-November, their long night begins, and they don't see the sun again until mid-January. A heavy price, indeed.

But what we all see when we see the Northern Lights is a deadly threat transformed into a thing of beauty. Certainly this is a gift we can all be happy to accept.

(10/4/00)