Zero Shadow Day

Bengaluru experienced Zero Shadow Day on 24th April at exactly 12.17 pm. Objects cast a shadow exactly downward, causing objects on the ground to have no visible shadow.

Why It Happens:

• The Earth’s axis is tilted by 23.5°.
• As Earth orbits the sun, the sun’s apparent path (solar arc) shifts north and south during the year.
• On Zero Shadow Day, at local noon, the sun is at the zenith (directly overhead) at that place.
• Only people living between the Tropic of Cancer and Tropic of Capricorn (i.e., in the tropics) experience Zero Shadow Days.
• Each city has different Zero Shadow Days, depending on its latitude.
• This phenomenon occurs twice a year, once around April 24 or 25 and a second time around August 18.

Broader Solar Movements to Know:

• Summer Solstice (~June 21): Sun overhead at the Tropic of Cancer (+23.5° latitude).
• Winter Solstice (~December 22): Sun overhead at the Tropic of Capricorn (–23.5° latitude).
• Equinoxes (~March 21 & September 23): Sun directly overhead at the equator (0° latitude).
• The solar arc takes about six months to move from one tropic to the other.