How Does the Sunspot Cycle Affect Earth?
ES2605  The Solar Wind

We now know that hot gases in the sun's outer atmosphere boil out into space, generating a "solar wind" that sweeps past Earth and the other planets. The solar wind streams out from the sun in all directions at speeds of around 400 km/s (about 900,000 miles per hour). Periods of intense solar activity occasionally result in "solar storms" when the particles reach Earth. Fortunately, we are shielded from most of the solar particles by an invisible "force field"—Earth's magnetic field.

The solar wind and Earth's magnetic field

3. Earth is 150 million kilometers from the sun, and the solar "wind" travels at about 400 km/sec. How long does it take particles from a solar storm to reach Earth? (Hint: Time = Distance / Speed. To convert from seconds to hours, divide the time in seconds by 3600.)

4. What do you think would happen if Earth's magnetic field became weaker or disappeared entirely?

5. In the illustration, where do you see weaknesses in Earth's magnetic shield—places where the magnetic field may allow solar wind particles near the surface?

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