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On Wed, 18 Oct 2000, Bonita wrote:
> Dear Sir,
>
> I live in Harrisburg, Pennsylvania and would like to know when the
> Northern Lights appear? Is it every year of occasionally? When are they
> scheduled to appear in my part of the country?
Hello,
The northern lights, or aurorae, are a phenomenon caused by energetic
particles from the sun slamming into Earth's atmosphere. The Earth's
magnetic field funnels these particles to the North and South Magnetic
Poles (the north magnetic pole is located over the Hudson Bay), so the
aurora are most often seen to the north. In fact, in northern Canada,
Alaska and Siberia, aurora are visible virtually every night.
When a magnetic storm from the sun hits the Earth, the aurora can be
visible from further south. At the latitude of Harrisburg (about 40
degrees), the aurora are rarely visible. It takes a strong magnetic storm
that happens only a few times a decade. And these events are fairly
random, so there is no good schedule. On average, though, stronger storms
occur during spring and fall, and more storms are occuring now than normal
(The sun goes through a cycle of activity every 11 years, and we are near
the peak of that activity now.)
Check out the Aurora page at http://www.geo.mtu.edu/weather/aurora/ for
more information on the aurora. They also have links to websites that can
give aurora forecasts.
Thanks for writing!
Sincerely,
Kurtis Williams
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