Suryakant Jena

On the evening of November 8, as the Earth's shadow envelopes its sole satellite for nearly one-and-half hours, the world will witness a thrilling and chilling spectacle of a 'Blood Moon' lunar eclipse.

Explaining the celestial phenomenon, Prof. Bharat Adur, Director, Akash Ganga Centre for Astronomy in Mumbai says, the lunar eclipse which comes exactly 14 days (two Tuesdays) after the October 25 partial solar eclipse shall be only partially visible in the rest of India in the evening as the sun sets.

Tomorrow, the Earth's looming shadow will cover the Moon and during this period it will appear a dark reddish colour, almost like a large drop of blood balanced in the sky... This phenomenon is called a 'Blood Moon' and it's an exciting spectacle, said Prof. Adur.

Why Blood Moon Happens?

The Earth will come between the Sun and Moon and the blue planet's monstrous shadow -- from a staggering distance of 3.93 lakh kms -- will shroud its small natural satellite, partially or fully, depending on the angle of alignment from where it is viewed.

The Sun is around 109 times bigger than Earth and over 148-million kms away, while the Earth is nearly four times larger than the Moon, with an average distance of 3,85 lakh kms separating them.

"In a total lunar eclipse, the Moon is entirely blanketed by the Earth's darkest shadow, called the 'umbra', and at this time, the Moon appears a dark-reddish colour, or what is called the 'Blood Moon' phenomenon," Prof. Adur said.

In scientific terms, it's called the 'Rayleigh Scattering' as during a lunar eclipse the only sunlight that reaches the Moon passes through the Earth's atmosphere, thus turning the Moon an apparent reddish colour.