The year 2018 has started off with a celestial bang. Come January 31, and the world will witness a rare Blue Moon total eclipse occurring after a gap of more than 150 years. This means it will essentially be the first sighting of this rare phenomenon for just about every human walking the Earth right now. Oh, what a great time to be alive!
The first eclipse of 2018 slated to occur on January 31 will be a total lunar eclipse of the second full moon, popularly known as the Blue Moon. The Blue Moon in itself is a rare phenomenon that takes place once in every two and a half years, on an average. The phrase ‘once in a Blue Moon’ traces its origin to the rarity of having two full moons in a single month. The blue moon is a rare occurrence because there is roughly a gap of 29.5 days between full moons, which makes it highly unlikely for two full moons to fit into a 30 or 31 day month cycle. This is also the reason why the month of February can never have a blue moon.
Since the blue moon occurs rarely, the odds of it passing through the Earth’s umbra are exceptionally low. The last time this skywatching delight took place was on March 31, 1866. However, in the future, we won’t have to wait another century-and-a-half to witness another Blue Moon total eclipse. As per predictions, the next one will take place on December 31, 2028, and then again on January 31, 2037.
During a partial or total lunar eclipse, the moon is often referred to as the ‘Blood Moon’, owing to the deep shade of orange that it takes on. Explaining the science behind this, NASA says, “The moon’s orbit around our planet is tilted so it usually falls above or below the shadow of the Earth. About twice each year, a full moon lines up perfectly with the Earth and sun such that Earth’s shadow totally blocks the sun’s light, which would normally reflect off the moon. The moon will lose its brightness and take on an eerie, fainter-than-normal glow from the scant sunlight that makes its way through Earth’s atmosphere. Often cast in a reddish hue because of the way the atmosphere bends the light, totally eclipsed Moons are sometimes called ‘blood moons’.”
For the Indian subcontinent as well as Eastern Europe and the Middle East, the eclipse will be visible with the Moon rise. Indonesia, central and eastern Asia, New Zealand and parts of Australia will able to get a fine view of rare phenomenon in the evening sky. In northwestern Canada, Alaska and Hawaii, the eclipse will be visible right from the start to finish. However, moonset will intervene with the viewing experience for North and Central America. The Pacific Ocean will turn toward the Moon as the eclipse gets underway in that region in the middle of the night.
The duration of totality of the eclipse will be 77 minutes, and the moon would track through the southern end of Earth’s shadow during this time. During the phase of total eclipse, the lower end of the moon is expected to take on a bright orange hue where as the upper limb will remain somewhat darker.