why do we have lunar eclipses?
Lunar eclipses occur when the Earth comes between the Sun and the Moon, casting a shadow on the Moon's surface. The moon orbits around the Earth, while the Earth orbits around the Sun. Therefore, at certain points in its orbit, the Moon aligns with the Earth and Sun in such a way that the Earth blocks the Sun's light from reaching the Moon's surface, resulting in a lunar eclipse.
Four factors contribute to the occurrence of lunar eclipses:
1. Alignment: For a lunar eclipse to occur, the Sun, Earth, and Moon must be nearly aligned in a straight line. This alignment allows the Earth to cast its shadow on the Moon.
2. Full Moon: Lunar eclipses exclusively happen during a full moon when the Moon is on the opposite side of the Earth from the Sun. This alignment ensures that the Earth's shadow falls on the Moon.
3. Tilted Orbit: The Moon's orbit around the Earth is slightly tilted relative to the Earth's orbit around the Sun. As a result, lunar eclipses do not happen during every full moon, but only when the alignment occurs near the points in the Moon's orbit where it intersects with the Earth's orbital plane.
4. Earth's Atmosphere: During a lunar eclipse, the Earth's atmosphere scatters and refracts some of the sunlight passing through it. As a consequence, this scattered light is filtered, resulting in the famous reddish color observed during a total lunar eclipse, often referred to as a "blood moon."
In conclusion, lunar eclipses occur when the Earth blocks sunlight from reaching the Moon due to their alignment and the Moon's tilted orbit.