Zero shadow day in Chennai today

This April 2017 file photo shows students from a school in Puducherry preparing for the zero shadow moment.

This April 2017 file photo shows students from a school in Puducherry preparing for the zero shadow moment.   | Photo Credit: S.S. Kumar

Step out at 12.07pm today to find your shadow exactly under you.

What does it mean?

A sub-solar point is when the sun is directly overhead at a particular latitude. When the sun is at the zenith (the highest point in the sky) its rays will be hitting a particular point exactly perpendicular to the surface.

This will make your shadow be exactly under you, making it look like there are no shadows. Take a small jump and you can see your shadow.

How often does it happen?

It occurs twice a year.

To know where exactly it is happening now and when it will happen next you can download the Zero Shadow Day app from the Astronomical Society of India.