20 May 2006

little black spots on the sun

On 11 March 2006, Art Bell mentioned the solar cycle forecast on Coast to Coast AM. Our sun was virtually devoid of sunspots in February 2006, so the solar minimum of the solar cycle has arrived.

Here's a NASA article explaining the arrival of the solar minimum:
Solar Minimum Has Arrived

Art talked about the solar maximum of solar cycle 19 around 1957-1958, a time when shortwave propagation was excellent. Intriguingly, there are predictions that the upcoming solar maximum will also have an unusually high count of sunspots. Increased sunspots results in increased ionization of the ionosphere. Perhaps I began this hobby with fortunate timing after all!

Here's a VOA News article about the solar cycle prediction:
Researchers make first sunspot prediction

What is the relation between the solar cycle and the ionosphere? According to Wikipedia, "the activity of the sun is associated with the sunspot cycle, with more radiation occurring with more sunspots." Conversely, "solar flares can prevent the ionosphere from reflecting or refracting radio waves." Combining these two items, "at the peak of the [solar] cycle there are typically more sunspots on the Sun, and hence more solar flares."

In a few years, I will have my first solar maximum as a shortwave listener, and it is shaping up to be a spectacle!

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