By Narottam Sahoo, Gujarat Science City

Ahmedabad: This Friday will have another Good Friday as the Friday night will bring the longest total lunar eclipse of 21^st century. In addition, the Red planet Mars will also to be closer to the red moon, casting a unique celestial phenomenon to observe and remember.

 

On July 27, the Sun, Earth and Moon are aligned, placing the moon opposite the sun in our sky, producing an eclipse as Earth’s shadow falls on the moon’s face. On the same night, the sun, Earth and Mars are also aligned, bringing Mars also opposite the sun in our sky, just like the full moon.

 

The full moon on the night of July 27-28, 2018, presents the longest total lunar eclipse of the 21st century. The total phase of the eclipse – called the totality will continue for 1 hour 42 minutes and 57 seconds. That’s in contrast to the shortest total lunar eclipse of this century, which occurred on April 4, 2015 and lasted 4 minutes and 48 seconds. And it’s in contrast to 2018’s other total lunar eclipse – on January 31, 2018, whose totality lasted 1 hour and 16 minutes.

 

A partial eclipse precedes and follows the total phase of the eclipse, each time lasting 1 hour and 6 minutes. So, from start to finish – on July 27-28, 2018 – the moon spends nearly 4 hours (3 hours and 55 minutes) crossing within Earth’s dark umbral shadow.

 

Adding to the excitement on eclipse night … this eclipse will happen on the same night that Earth is passing between the sun and Mars, placing Mars at opposition in our sky. In one of the sky’s wonderful coincidences, the Mars opposition happens on July 27, too. It’s not just any Mars opposition, but the best Mars opposition since 2003. Mars is very bright and red throughout July and August, 2018. But the Friday eclipse night will be a very special night.

 

During the long total phase of the July 27, 2018 lunar eclipse – the totality – the moon will turn red from sunlight filtering through Earth’s atmosphere onto the moon’s surface. And Mars will be near the moon, exceptionally bright – brighter than since 2003 – and red in colour also.

 

Eclipse timing and visibility:

 

This lunar eclipse is primarily visible from the world’s Eastern Hemisphere (Europe, Africa, Asia, Australia and New Zealand).

 

The first part or phase of lunar eclipse will see the moon fall under the earth’s shadow. This phase is known as the penumbral eclipse (initial stage). The event is said to begin from 11:44 pm on July 27. The first phase of the lunar eclipse is expected to set in from 11:54 pm. The total lunar eclipse is estimated to set in from 1:00 am on July 28.

 

For the second phase, as the moon continues on its orbit, there will be another partial lunar eclipse, which will be visible from around 2:43 am. The moon will be in perfect alignment with the sun and the earth.

 

 

Sl. No.	Eclipse phases	Time in Ahmedabad
1	Penumbral Eclipse begins	27 Jul, 22:44:47
2	Partial Eclipse begins	27 Jul, 23:54:27
3	Full Eclipse begins	28 Jul, 01:00:15
4	Maximum Eclipse	28 Jul, 01:51:44
5	Full Eclipse ends	28 Jul, 02:43:11
6	Partial Eclipse ends	28 Jul, 03:49:00
7	Penumbral Eclipse ends	28 Jul, 04:58:38

 

 

The eclipse will be visible all across the globe, except North America. It can be best viewed from Australia, New Zealand, Africa and Asia.

 

Long lasting total lunar eclipse

 

For an especially long-lasting total lunar eclipse of 1 hour and 43 minutes to occur, the moon has to pass through the central part of the Earth’s shadow. The previous total lunar eclipse on January 31, 2018, didn’t last as long (1 hour and 16 minutes) because the moon passed to the south of the shadow’s center; and the next total lunar eclipse on January 21, 2019, won’t be as long either (1 hour and 2 minutes) because it’ll pass to the north of the shadow’s center.

 

In 2018, the July full moon and July lunar apogee – the moon’s most distant point from Earth in its monthly orbit – both fall on the same date: July 27, 2018. Therefore, the July 2018 full moon showcases the most distant and smallest full moon of the year.

 

Sometimes called an apogean full moon (or micro-moon or mini-moon), this smaller and slower-moving full moon takes more time to cross the Earth’s shadow than does a full moon that’s closer to Earth and moving faster in orbit. That’s why a full moon at or near lunar apogee adds to the duration of a total lunar eclipse.

 

The longest possible total lunar eclipse is 1 hour and 47 minutes. In fact, the longest total eclipse of the 20th century (1901 to 2000) occurred on July 16, 2000, with a duration of 1 hour and 46.4 minutes. That’s because, at greatest eclipse, the center of the lunar disk aligned almost perfectly with the center of the Earth’s shadow.

 

Red Moon and Red Planet

The moon turns deep red or reddish brown during eclipses, instead of going completely dark. That’s because some of the sunlight going through Earth’s atmosphere is bent around the edge of our planet and falls onto the moon’s surface. Earth’s air also scatters more shorter – wavelength light (in colours such as green or blue); what’s left is the longer-wavelength, redder end of the spectrum.

Special outreach activities on Moon Festival in Science City, Community Science Center 

In order to educate, engage and experience the unique celestial phenomenon among children and community members at large, a special outreach programme, Moon Festival has been organised in Science Day from 20th July 2018 to 27th July 2018. The programme has been organised to mark the 50th anniversary of Man landing on the Moon on 20th July and the longest lunar eclipse in the century on  27th July.

Everyday, there is a live scientific interaction with eminent space scientists along with screening of IMAX 3D film on Walking on the Moon and guided tour to Hall of Science and Hall of Space have been organised.

For thousands of years, eclipses of earth’s lone natural satellite have garnered awe and fear. Now that science has explained the celestial mechanics at play, we can all simply enjoy the cosmic ballet.

 

For everybody the eclipse is a unique opportunity to admire and celebrate the beauty and inspiration of the celestial experience.

 

The experience of such a moment triggers questions on the cosmos, our Earth in space, and our human condition – a shared unforgettable experience that crosses boundaries of language, race, religion and culture.