Look up tonight! The biggest full moon of the year is about to appear in the night sky, let's feel the cosmic romance together

We have just said goodbye to the "most anticipated comet of the year", and tonight we will usher in the "largest full moon of the year", and cosmic-level romance is coming.

According to Xinhua News Agency, the moon will reach a full moon at 19:26 on October 17. This full moon is closest to the moon's perigee, so the full moon above our heads tonight is not only a "super moon" but also the largest full moon of the year.

The largest full moon of the year, photographed at the ruins of the Temple of Poseidon in Sounion, Greece on May 26, 2021. Source: Xinhua News Agency

When will the largest full moon of the year appear? How can we appreciate it? Xu Yuhua, a popular science lecturer of the Zhejiang Astronomical Society, accepted an interview with a reporter from Chao News and "revealed" the "fat moon" in the night sky tonight.

"Look up at the bright moon"

The largest full moon of the year will appear in the night sky tonight

The largest full moon of the year will climb into the night sky tonight. Why is it so special? It all starts with the moon's orbit.

The orbit of the moon around the earth is not a perfect circle, but an ellipse. Therefore, when the moon is full, the distance between the moon and the earth is not the same. They are always "far away and near". Xu Yuhua told reporters that the full moon closest to the earth in a year is the largest full moon of the year. The largest here actually refers to the largest apparent diameter, that is, the largest moon people see. According to astronomical observations, the same full moon has a 14% larger apparent diameter and a 30% larger apparent area at perigee than at apogee.

The largest and smallest full moons of 2019 (collage) Source: Xinhua News Agency

The moon waxes and wanes. Xu Yuhua said that the cycle from one full moon to the next is called the "synodic month" in astronomy, which occurs about every 29.5 days. In this process, people will slowly appreciate the different phases of the moon, such as the crescent moon, the waxing moon, the waxing gibbous moon, the full moon, the waning gibbous moon, etc., as the moon moves.

A full moon is a lunar phase that occurs when the moon is fully illuminated by the sun and the moon and sun are on opposite sides of the earth. Tonight is the largest full moon of the year.

"The moon hangs brightly in the autumn sky"

The moon may be a "ruby disk" tonight

The moon looks big and bright because it is near the perigee. Xu Yuhua told reporters, "According to the principle of near big and far small, when the full moon occurs, the closer the moon is to the earth, the bigger the full moon people see, and it also appears brighter than usual."

"When I was young, I didn't know the moon, I called it a white jade plate." Everyone should be familiar with Li Bai's classic description of the moon. The white and round moon hanging in the sky looks like a "white jade plate." But Xu Yuhua told everyone that the largest full moon of the year seen tonight may be reddish in color.

A series of images of the "super moon" taken in Beijing on March 21, 2019. Source: Xinhua News Agency

There was a rumor among the people that "if the moon changes color, there will be disasters", and that "full moon" and "blood moon" are "ominous signs". Xu Yuhua refuted this rumor, saying that there is no basis for such a statement, and that the waxing and waning of the moon and the change of its color are all normal astronomical phenomena.

"The waxing and waning of the moon is just a normal phenomenon caused by the elliptical orbit of the moon around the earth and the changes in the synodic month, and has nothing to do with disasters." He also explained, "The reddish color of the moon is not because the moon itself has turned red, but because of atmospheric scattering. The longer wavelength red can more easily penetrate the atmosphere, making the low-lying moon look redder."

"We are all here together"

How to enjoy the biggest full moon of the year?

"Let's watch the moon rise together..." The song is melodious and the full moon is heart-warming. How can ordinary people appreciate this year's largest full moon? In fact, as long as night falls quietly and you look up, you will have a visual feast. "Appreciating the year's largest full moon is the same as ordinary moon appreciation. It is visible to the naked eye. The full moon rises at sunset and sets at sunrise. It can be seen all night long." Xu Yuhua said.

The moon is bright over the sea, and people all over the world can see it. The ancients were right. No matter where we are, we are looking at the same moon. Xu Yuhua said: "If the weather is fine, people all over the country can see the biggest full moon of the year."

The "supermoon" is waiting for everyone to enjoy, but if you accidentally miss this "white and fat" moon tonight, don't worry, you will have another chance next month. Xu Yuhua said that although tonight is the largest full moon of the year, the "supermoon" is not a rare astronomical phenomenon, and it basically occurs every year. "This year alone, there have been four 'supermoons', on August 20, September 18, October 17 and November 16, so next month you will have another chance to enjoy the big and round moon."

The "supermoon" photographed under the Leifeng Pagoda in West Lake, Hangzhou on September 18, 2024. Source: Liu Fang, Chao News