Most Probable Topic Series
- Zero Shadow Day (ZSD) is an astronomical phenomenon during which the Sun is exactly overhead, and vertical objects cast no shadow at local noon.
- Occurrence:
- Happens twice a year at places located between the Tropic of Cancer (23.5°N) and the Tropic of Capricorn (23.5°S).
- Exact date varies with latitude.
- Scientific Reason:
- Caused by the Earth’s axial tilt (23.5°) and its revolution around the Sun.
- When the Sun’s declination equals the latitude of a place, ZSD occurs.
- Frequency Related to Solar Movement:
- Dakshinayana: After 21st June (Summer Solstice), Sun moves southward towards the Tropic of Capricorn.
- Uttarayana: After 22nd December (Winter Solstice), Sun moves northward towards the Tropic of Cancer.
- Characteristics:
- At local noon, the Sun is directly overhead.
- Shadows of vertical objects become zero or disappear for a brief duration (~1 to 1.5 minutes).
- Key Point:
- Although the exact Zero Shadow moment is instantaneous, the phenomenon is visible for a short observable period.
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