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Global Warming and Astronomy: Part Two |
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Written by Jim Stepp
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First,
I would like to say that I believe global warming is occurring. The evidence is overwhelming that the Earth
has warmed over the past 200 years.
Growing seasons have increased by as much as two to three weeks in many
areas, and that could only happen when the temperature rises.
The question is has man caused the warming or is it
100% natural? I was taught a long time
ago never to trust absolutes. So, I have
difficulty believing that man is the only cause of global warming and with the
current evidence of increased carbon levels in the atmosphere I have trouble
believing that this warming cycle is totally natural.
With this in mind I want to give you some information
about non-Earth based factors that could be contributing to global warming.
The sun is the source of essentially all heat in the climate
system. As the Sun ages it gets brighter
and its energy output increases slightly.
Thus, as time goes on the Sun will cause the Earth to warm. This is a very long process, and most likely
has only a small effect on the Earth.
More immediate is the Sun's 11-year sunspot
cycle. When the Sun is active and has
many sunspots, the Earth is warmer than when there are few sunspots. Studies have shown that the period of time
known as the Little Ice Age occurred when sunspots were missing from the Sun
for an extended period of time.
Currently we are moving towards a sunspot maximum in 2010. Astronomers believe this sunspot maximum may
be one of the most intense in the nearly 400 years we have records of solar
activity.
Another
astronomical event that affects climate is the orbital variations in the Earth's
orbit. The Earth's orbit is not
circular; it is an ellipse or oval. The
Earth's distance from the Sun changes as its orbit changes, thus the energy we
get from the Sun changes. This is called
the Milankovitch cycle.
A third factor comes from the Earth's axis tilt. Currently the Earth is tilted 23.5
degrees. This tilt changes over
time. A zero degree tilt would create a
situation where the days were always the same length and seasons as we know it
would end. There would always be 12
hours of daylight and 12 hours of night.
A larger tilt in the axis would bring about larger shifts in day light
and night and thus would cause summers and winters to be much more severe.
The length of this article limits the number of
factors I can give to you, but if you are interested in finding out more about
space related factors for global weather, try looking at these two sites: http://www.sciencedaily.com/releases/2002/06/020607073439.htm
or http://aa.usno.navy.mil/faq/docs/seasons_orbit.html.
02/01 Sunrise
6:56 a.m., Sunset 4:35 p.m.
02/01 07:13 a.m. Venus 0.6 degrees north of Jupiter
02/01 03:00 p.m. Mercury 3.2 degrees north of Neptune
02/03 12:00 a.m. Jupiter 4.1 degrees north of Moon
02/04 06:00 a.m. Venus 4.3 degrees north of Moon
02/04 12:58 p.m. halfway point between the start of
winter and the start of spring
02/06 01:18 p.m. Mercury 3.6 degrees north of Sun -
Mercury becomes a morning object.
02/06 06:00 p.m. Mercury 5.1 degrees north of Moon
02/06 10:00 p.m. Sun 1.0 degrees north of Moon
02/06 10:44 p.m. New Moon
02/07 Chinese New Year
02/07 05:00 a.m. Neptune
0.4 degrees north of Moon
02/08 Sunrise
6:47 a.m., Sunset 4:46 p.m.
02/08 Jules Verne's 180th Birthday (1828)
02/08
11:36 a.m. Mercury Closest Approach (distance to earth: 0.649 AU)
02/09 04:00 a.m. Uranus 2.6 degrees south of Moon
02/10 11:00 p.m. Neptune
0.3 degrees south of Sun
02/13 07:56 p.m. Moon at perigee - closest to the
Earth (230,115 miles or 370,255 km)
02/13 10:33 p.m. First Quarter Moon
02/15 Sunrise
06:37 a.m., Sunset 04:57 p.m.
02/16
Planet Head Day (Look for further information in the UTimes
02/16
3:00 a.m.Mars 1.0 degrees north of Moon
02/20
8:42 p.m. Partial lunar eclipse begins
02/20
10:00 p.m. Totality lunar eclipse begins
02/20
10:26 p.m. Greatest lunar eclipse
02/20
10:30 p.m. Full Moon
02/20
10:51 p.m.Total lunar eclipse ends
02/21
12:09 a.m. Partial lunar eclipse ends
02/21
4:12 a.m. Moon Close to Saturn, Separation=3.39°, PA=34.2°
02/22
Sunrise 06:25
a.m., Sunset 05:07 p.m.
02/24
2:00 a.m. Saturn Closest Approach (distance to earth: 8.291 AU)
02/24
5:00 a.m. Saturn Opposition (distance to earth: 8.291 AU)
02/27
3:47 a.m. Mercury 1.1° Venus
02/27
8:26 p.m. Moon at Apogee (distance to earth center: 404403.4 km)
02/28
2:18 a.m. Mercury Half phase
02/28
9:18 p.m. Last Quarter
02/22
Sunrise 06:12
a.m., Sunset 05:17 p.m.
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