The moon is leaving us

© NASA / Getty / The Atlantic

The moon is moving away from us.

Each year our moon moves distinctly, inexorably farther from Earth, just a tiny bit, about an inch and a half, an almost imperceptible change. There is no way to stop this slow ebb, no way to go back. The forces of gravity are invisible and unwavering, and no matter what we do or how we feel about them, they will continue to push the moon. For millions of years, we will continue to separate.

Given this rather melodramatic description, you might be wondering: Ain’t you better to think than the moon? Well no, not really, because I am a space reporter and it is my job to contemplate the celestial bodies and to write about them. And also because a representation of this phenomenon was played out recently in China during the festivities of the Mid-Autumn Festival, which marks the full moon closest to the autumn equinox. A giant balloon designed to look like the moon, craters and all, freed itself and rolled down the street. Unscripted video footage of the moment shows two people chasing the massive moon as it moves away. Bye!

The moon was closer. When it first formed about 4.5 billion years ago, molded from rocky debris that floated around the Earth, the moon was spinning 10 times closer to the planet than it did. does it today. The debris, scientists believe, came from a collision between Earth and a mysterious object the size of Mars. Fresh out of the cosmic oven, the moon was hot and molten, glowing in the night sky. Back then, say scientists, the moon was moving about eight inches a year away.

[Read: Everyone can chill out about the moon]

Our planet and its moon were always going to separate like this. The gravity of moons, no matter how small in comparison, can still pull at their planets, causing larger worlds to bulge slightly. On a planet covered with oceans like ours, the effect manifests itself in changing tides. The moon is pulling at our oceans, but these oceans are retreating, causing the moon to accelerate in its orbit. And “if you accelerate in orbit around the Earth, you escape the Earth more successfully, so you orbit at a farther distance,” explained James O’Donoghue, a planetologist at JAXA, the space agency. Japanese. Scientists call this phenomenon “lunar retreat” – a delightful term, as I would rather imagine the moon having fun on a relaxing jaunt, bending its rocky body into various yoga poses, rather than slowly fantasizing about Earth.

Scientists measured this recoil by projecting lasers at mirrors that Apollo astronauts left on the moon, using this data, along with other sources, to estimate past motions. The rate of lunar retreat has changed over the years; the peaks coincided with important events, such as a meteor bombardment on the moon and fluctuating ice ages on Earth. The constant recession has influenced the Earth beyond the ebb and flow of its tides. The forces that push the moon away from us also slow down the planet’s rotation, thus lengthening the length of our days. In the beginning, when the moon was approaching us and the Earth was spinning faster, a day lasted only four hours. At the current rate of lunar retreat, it would take a century to add about two more milliseconds to the length of the day.

The moon should continue to drift this way for the very scientific measurement of forever. And, despite the premise of an upcoming action movie called Falling moon, it’s not going to hit us either. Someday, in about 600 million years, the moon will orbit far enough that humanity will lose one of its oldest cosmic sites: total solar eclipses. The moon will not be able to block sunlight and cast its own shadow on Earth. But the Moon will remain tied to the Earth, watching a very different version, much hotter of the planet, as the oceans begin to evaporate. Of course, a few billion years later this, the sun will completely derail the moon, and so will the earth, when it runs out of fuel, expand and engulf the inner solar system in a spectacular act of stellar death.

[Read: The mystery of moon water ]

This weekend I looked through a telescope for the first time, into a much quieter solar system. (I know, right? I’m a space reporter!) A neighbor had one set up on the roof of my building, and I tried to be careful as he explained the different objectives and their amplifying capacity, but I was too excited, just thinking, Let me see, let me see. I had seen the moon as a two-dimensional luminous globe in the sky, with dark specks that play tricks on our brains, making us see familiar patterns where there are none. People have interpreted these glyphs in several ways: a human face, the silhouette of a rabbit. What did the moon see in us? “The moon has been observing Earth closely for longer than anyone,” Japanese writer Haruki Murakami wrote in her novel. 1Q84. “He must have been a witness to all the phenomena happening – and all the deeds done – on this earth. The moon is still watching. What should he think now, after such a horrible year and a half?

My neighbor rotated his telescope in the cloudless sky. There was Jupiter and its sinuous, faint but unmistakable stripes, and three tiny dots of light just to the side – its largest moons. There was Saturn, a perfect ball, its rings sticking out either side. And then there was the moon: covered in craters, craters and shadows, so richly textured that the skin of my fingers tingled at the sight, as if I was rolling the moon in my hand like a marble, feeling its edges. jagged. I decided not to spoil the moment for everyone on the roof that night by telling them that the moon was slowly but surely moving away from us. The experience of distance – of our families, of a time of relative normality – had already tormented many of us enough. Better to focus on the small image in the lens, seeing the moon correctly for the first time. Maybe it was wishing Earth a very long goodbye, but it was nice to say hello to her.