Bandar Seri Begawan – Vertical objects became shadow less at around mid-day today, Wednesday, April 1, 2020, in Brunei Darussalam. Cosmic observers tried out simple experiments by just placing sticks or cylindrical objects vertically on the ground under the sun as well as by observing surrounding environment for changes in the shadow.
Brunei Darussalam was located at the Subsolar Point (the sun was at a 90 degree angle from the Earth) at exactly 12:24 pm for areas around BSB & Temburong, 12:25 pm for Tutong and 12:27 pm for Kuala Belait. At that instance known as “Zero Shadow”, the sun was directly overhead or at the Zenith shining its rays to a point exactly perpendicular to the ground. This has caused shadow exactly underneath, making it looks shadow less.
The phenomenon occurs twice every year. If you missed it, the next will be on September 9th, 2020. On Earth, it can only happens in areas between the tropics i.e. 23¹/₂ degrees north or south of the equator.
Some significances of this phenomenon were:
(a) In Falak Syarie, Zuhur prayer starts when the sun begins to decline after reaching its highest point in the sky (Zawal);
(b) On June 19, 240 BC, a Greek, Eratosthenes used the noon time Sun at Alexandria and Syene with simple geometry to determining the size of the Earth;
(c) Sundial, the earliest type of timekeeping device, which indicates the time of day by the position of the shadow of some object exposed to the sun’s rays.
A live online video of the Zero Shadow Day experiment was also broadcasted by PABD as part of Astronomy at Home initiative.