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| Brief
Explanation of the Moon Phases |
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The phases of the moon
are caused by the relative positions of the earth, sun,
and moon. The moon goes around the earth, on average,
in 27 days 7 hours 43 minutes.
The sun always illuminates
the half of the moon facing the sun (except during lunar
eclipses, when the moon passes thru the earth's shadow).
When the sun and moon are on opposite sides of the earth,
the moon appears "full" to us, a bright, round
disk. When the moon is between the earth and the sun,
it appears dark, a "new" moon. In between,
the moon's illuminated surface appears to grow (wax)
to full, then decreases (wanes) to the next new moon.
The
edge of the shadow (the terminator) is always curved,
being an oblique view of a circle, giving the moon its
familiar crescent shape. Because the "horns"
of the moon at the ends of the crescent are always facing
away from the setting or rising sun, they always point
upward in the sky. It is fun to watch for paintings
and pictures which show an "impossible moon"
with the horns pointed downwards. |
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Geomagnetic
Field |
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| Solar
X-rays: |
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| Geomagnetic |
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The X-ray Solar status monitor downloads
data periodically from the NOAA Space Environment Center
FTP server. The previous 24 hours of 5 minute Long-wavelength
X-ray data from each satellite (GOES 8 and GOES 10)
is analyzed, and an appropriate level of activity for
the past 24 hours is assigned as follows:
Normal: Solar X-ray flux is quiet (< 1.00e-6 W/m^2)
Active: Solar X-ray flux is active (>= 1.00e-6 W/m^2)
M Class Flare: An M Class flare has occurred (X-ray
flux >= 1.00e-5 W/m^2)
X Class Flare: An X Class flare has occurred (X-ray
flux >= 1.00e-4 W/m^2)
Mega Flare: An unprecedented X-ray event has occurred
(X-ray flux >= 1.00e-3 W/m^2)
The designation "Mega Flare" was chosen by
Kevin Loch when the status monitor was created on March
4, 1999.
There is no "official" designation for flares
in this range.
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