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Solar Wind
Fri Oct 08, 2004
Listen in RealAudio 
Hi, I'm Bryan Yeaton, and this is The Weather Notebook. Wind is the movement of air
parallel to the surface of the planet. As we observe it on Earth it is strictly an
atmospheric event. But today on the show, we explore another kind of wind, one of an
extraterrestrial nature: something called the "solar wind."
The solar wind is entirely different in origin from, say, a summer breeze or even a
hurricane. Instead, the solar wind is a stream of electrons, neutrons and protons:
charged particles that rush outward from the sun in all directions at speeds of up to a
million miles per hour. The temperature of the particles in this blowing stream starts
out at about 2 million degrees Celsius, and cools to perhaps only 200,000 degrees by
the time these ions reach the outer influences of Earth's magnetic field. But the solar
wind is not what delivers heat to our planet — that comes from solar radiation that
penetrates the earth's atmosphere.
The solar wind, instead, slams into the Earth's magnetic field several hundred miles
above the daytime side of the planet, where it is deflected to the north and south. In a
sense, the Earth's magnetic field captures the solar wind, distributing the charged
particles toward the poles where they can excite the air molecules they encounter,
causing them to glow in a ghostly dance of light known as the aurora borealis and
aurora australis. Or the northern and southern lights.
Solar wind doesn’t really have much effect on earthly weather although it can do a
number on your cell phone, pager, or the reception of your favorite radio station.
Major funding for The Weather Notebook comes from Subaru of America. Our show is
a program of the Mount Washington Observatory, home of the World’s Worst Weather
(actually, some of us kinda like it). Find us online at www.mountwashington.org.
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