The angle at which sunlight hits the Earth at different latitudes is primarily influenced by the tilt of the Earth's axis and its orbit around the Sun. Here are the key factors that contribute to this phenomenon:
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Axial Tilt: The Earth is tilted on its axis at an angle of approximately 23.5 degrees relative to its orbital plane. This tilt means that during different times of the year, different latitudes receive varying amounts of sunlight. For example, during the summer solstice in the Northern Hemisphere, the North Pole is tilted towards the Sun, resulting in more direct sunlight and longer daylight hours. Conversely, during the winter solstice, the North Pole is tilted away from the Sun, leading to lower angles of sunlight and shorter days.
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Latitude: As latitude increases (moving away from the equator toward the poles), the angle at which sunlight strikes the surface becomes more oblique. This oblique angle spreads the light over a larger area and reduces the intensity of the sunlight, which is why polar regions tend to be colder than equatorial regions.
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Earth's Orbit: The Earth's elliptical orbit around the Sun also plays a minor role in how solar energy is distributed across latitudes. However, the axial tilt has a much more significant impact on seasonal variations.
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Time of Year: The Earth's tilt causes variations in the sun's path across the sky throughout the year, affecting the angle of sunlight at different times. For instance, around the equinoxes, the Sun is directly overhead at the equator, while at the solstices, it reaches its highest point in the sky at different latitudes (23.5° north or south) depending on the time of year.
These factors combined result in the sunlight hitting different latitudes at different angles, leading to variations in climate, vegetation, and ecosystems across the globe.
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