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Solsystem
Hvorfor bliver det forår, efterår, sommer og vinter.. I ved.. og hvorfor nogle dage er lige lange.. dag og nat.. hvis I forstår...
Svar #2
12. februar 2006 af fixer (Slettet)
Svar #3
12. februar 2006 af Lemin (Slettet)
hvor kan jeg finde en side om det ?? Hvad skal jeg bruge som søgeord ?
Svar #4
12. februar 2006 af Lemin (Slettet)
Svar #6
12. februar 2006 af fixer (Slettet)
http://www-spof.gsfc.nasa.gov/stargaze/Sseason.htm
Svar #7
12. februar 2006 af Lemin (Slettet)
Svar #12
13. februar 2006 af Lemin (Slettet)
The boundary AB between sunlight and shadow--between day and night--is always perpendicular to the Earth-Sun line, as it was in the example shown at the beginning.
But because of the tilted axis, as each point on Earth is carried on its daily trip around the rotating Earth, the part of the trip spent in daylight (unshaded part of the drawing) and in the shadow (shaded) are usually not equal. North of the equator, day is longer than night, and when we get close enough to the north pole, there is no night at all. The Sun is then always above the horizon and it just makes a 360-degree circuit around it. That part of Earth enjoys summer.
A mirror-image situation exists south of the equator. Nights are longer than days, and the further one gets from the equator, the larger is the imbalance--until one gets so close to the pole that the sun never rises. That is the famous polar night, with 24 hours of darkness each day. In that half of the Earth, it is winter time.
Half a year later, the Earth is on the other side of the Sun, that is, the Sun's position in the above drawing should be on the right, and the shaded part of the Earth should now be on the left (light and dark portions in the drawing switch places). The Earth's axis however has not moved, it is still pointed to the same patch of sky, near the star Polaris. Now the south pole is bathed in constant sunshine and the north one is dark. Summer and winter have switched hemispheres.
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