Why does the Moon turn red during a lunar eclipse? Explained
New Delhi, Nov 18: The Partial Lunar Eclipse (Chandra Grahan) will occur on Friday. It is the longest lunar eclipse in 580 years and will be visible from parts of India as it lasts for about three and a half hours.
Chandra Grahan Start Time and Duration
The Chandra Grahan will start at 12.48 pm and ends at 4.17 pm, Director of Research and Academic at MP Birla Planetarium Debiprosad Duari told PTI. Precisely, the eclipse will be for 3 hours 28 minutes and 24 seconds. The maximum partial eclipse will be visible at 2.34 pm as 97 per cent of the moon will be covered by the Earth's shadow.
The rare phenomenon will be visible from a few areas in Arunachal Pradesh and Assam, Director of Research and Academic at MP Birla Planetarium Debiprosad Duari told PTI. "A few areas in Arunachal Pradesh and Assam will experience the last fleeting moments of the partial eclipse just after the moonrise, very close to the eastern horizon," he explained.
The last time a partial lunar eclipse of such length occurred was on February 18, 1440, and the next time a similar phenomenon can be witnessed will be on February 8, 2669, he said.
The penumbral eclipse, which occurs when the sun, earth, and the moon are imperfectly aligned, will begin at 11.32 am and end at 5.33 pm, Duari added. People from Uttar Pradesh, Bihar, Jharkhand, West Bengal, and Odisha can watch the penumbral eclipse.
Why Moon Turns Red During Eclipse?
One question that comes to people's mind is why does the Moon turn during a lunar eclipse.
The face of the moon turns a shade of red during a lunar eclipse when some light hits the lunar surface passing through the Earth's atmosphere, giving a rosy glow to the Moon.
It is for the same reason why the sky looks blue during the day and the Moon turns red during the sunsets. "Sunlight bends and scatters as it passes through Earth's atmosphere. In air, colors at the blue and violet end of the rainbow scatter more widely than colors like red and orange. Widely scattered blue light tints the sky when the Sun is overhead on clear days. Redder light travels a straighter path through the air; we only see it scattered throughout the sky around sunrise and sunset, when sunlight has traveled through a thick slice of Earth's atmosphere before reaching our eyes," as per NASA.
Some of this heavily filtered morning and evening light hits the lunar surface during the lunar eclipse.
"The eclipsed Moon is dimly illuminated by red-orange light leftover from all of the sunsets and sunrises occurring around the world at that time. The more dust or clouds in Earth's atmosphere during the eclipse, the redder the Moon will appear," the NASA added.