In the coming days, as the Sun
makes its way across the sky, moving towards the north with each passing day,
depending upon where you live, the Sun will pass through the Zenith. This is
Zero Shadow Day. Zenith is the point exactly above your head wherever you
stand. Given the earth is a sphere-globe, this point varies from place to place
with respect to the sky.
At any other point, with the Sun
facing you at an angle, your shadow will be cast on the ground around you. As
the sun reaches higher in the sky, the length of the shadow reduces and on this
day, when the sun is exactly above your head, it casts a shadow exactly below
you. Since you stand on this shadow, you don’t really see your shadow making your
shadow invisible… or Zero shadow.
With the Earth titled at an angle
of 23.5 degrees (as the globes are made), as the earth moves around the Sun,
the sun appears to move from north to south, appearing at zenith on two days of
the year for all people living between the Tropic of Cancer and Tropic of
Capricorn. The two days occur in April-May and August every year, with August
being the monsoon and April, a summer month, the chances of observing Zero
Shadow Days are higher during this time.
This is one of the easiest astronomical phenomena that can be observed without the use of any instrument.
People at
Mangaluru will observe Zero Shadows at 12:28pm on 24th of April and
at Udupi on 25th April at 12:29pm. People in Bengaluru will have
their Zero Shadow moment on the 24th of April at 12:18pm.
The following are the dates of
Zero Shadow day for the rest of Karnataka:
|
22 Apr
: Mysore, Madikeri |
01 May
: Hubli, Hospet, Bellari |
The shadows for the above place
will disappear for a minute between 12:15pm for eastern and 12:35pm for western
parts of the state.
In order to observe Zero Shadow,
an object needs to have a equal or increasing width from top to bottom, like a
Cylinder, Cube or a Cone. Poles, Traffic Cones or an Inverted Glass Tumbler.
Humans have a broader upper body than our lower half and hence would cast a a
very small amount of shadow which will
be minimum on Zero Shadow Day.
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