Supermoon : All about the phenomenon

A supermoon happens when the full moon coincides with the moon's closest approach to Earth in its orbit. Supermoons make the moon appear a little brighter and closer than normal, although the difference is hard to spot with the naked eye. The first supermoon of 2019 was the Super Blood Wolf Moon on Jan. 20-21, and two more supermoons will follow on Feb. 19 and March 21.

The moon's orbit around the Earth is not a perfect circle. It has an average distance of 238,000 miles (382,900 km) from Earth, but its apogee and perigee — the closest and farthest approaches from Earth — change every lunar month.

A supermoon needs two key ingredients to occur. The moon needs to be at its closest approach, or perigee, to the Earth in its 27-day orbit. The moon also needs to be at the full phase, which happens every 29.5 days when the sun fully illuminates the moon. Supermoons only happen a few times a year (at most) because the moon's orbit changes orientation while the Earth orbits the sun — that's why you don't see a supermoon every month.

The moon appears as much as 30 percent brighter and 14 percent larger than usual, but it's very hard to spot the difference with the naked eye.

The supermoon may look especially large to you, however, if it's very close to the horizon. But that has nothing to do with astronomy and everything to do with how the human brain works. This effect is called the "moon illusion" and may arise from at least a couple of different things. Scientists suggest that perhaps the brain is comparing the moon to nearby buildings or objects, or perhaps our brain is just wired to process things on the horizon as bigger than things in the sky.

Learn what makes a big full moon a true 'supermoon' in this SPACE.com infographic.

(Image: © Karl Tate/SPACE.com)

Here are some clicks of the Supermoon as taken on 19th February, 2019. The pictures are from rooftop of IIST Hostel, taken with a Samsung Galaxy A6.