How the Earth and Moon Fell in Love

This is a love story that began one day, about 4.5 billion years ago, when a smaller rock ran head first into a bigger rock.

Smaller rock, distracted by recent text message, poses danger to other rocks in space.

NPS / Kat Gardiner

Ka-Boom!

NPS / Kat Gardiner

The smaller rock, eventually called the Moon, was horribly embarrassed.

“I’m so sorry!” the smaller rock exclaimed. “I was rushing on my way to the next solar system for an appointment and now I’ve completely come apart. And it must be a Monday because I spilled my carbon dust with extra foam all over myself, too.”

NPS / Kat Gardiner

Pssst...Here's Some Science Background

The prevailing scientific theory is that the Moon formed when a Mars-sized asteroid slammed into Earth, exploding bits of our planet and this asteroid into the cosmos. Many theories have come before and perhaps we will see new theories develop in the future. This is the beauty of the scientific method!

The Earth, who had been struck by the smaller rock, was a little dazed – and not just from the collision. There was something interesting about this smaller rock.

Many of the best romances began with a little embarrassment.

NPS / Kat Gardiner

“Why don’t you stay awhile and catch your breath?” suggested the Earth. The smaller rock needed to catch more than just its breath - parts of it were now floating off into space.

With all its belongings scattered into space and their surface transformed into a magma ocean – whether from the collision or complete mortification, or perhaps both - it was hard for the smaller rock to gather the momentum to get up and go. Plus, there was something magnetic about this bigger rock. The smaller rock almost didn’t feel it was possible to leave.

“OK,” the smaller rock said. “I guess I could stay awhile. What’s your name?”

Awhile turned into 4 billion years. During this time, the smaller rock gathered what was left of itself and transformed into the Moon, and the Moon and the Earth fell in love.

NPS / Kat Gardiner

The Moon started to orbit around the Earth, but at first the Earth rotated too quickly! Back in those days, the Earth completed one rotation in just 6 hours. Winds blew fast and furious, and just like the movie franchise to come, it seemed like they would never stop.

“Earth,” cried the Moon, “Can you slow down? It’s hard to get to know you when you turn away from me so quickly.”

NPS / Kat Gardiner

Over many millions of years, the Earth learned to slow down. But there was another problem. Prior to the arrival of the Moon, the Earth had been a fairly unlivable place, mainly because of the Earth's wobble. Life could not form on Earth with its unpredictable behavior – only the hardiest of bacteria could survive with weather like winter one day and summer the next. The Earth was very ashamed of this – it was the only planet in the solar system that could provide the right conditions for life to flourish, yet it couldn’t quite get the whole thing off the ground. The Earth needed help.

“Moon," said the Earth. “We have spent many wonderful moments together and I feel ready to take our relationship to the next level. You have a good influence on me – especially your gravitational force. You’ve helped me to slow down, and I really appreciate the time we have together as the Universe expands. I would like to settle down and create a home, and believe I can make that happen with your help. Can you help me to stop wobbling, so that I am a hospitable place for life?”

The Moon agreed.

They read about yoga and practiced good posture but mostly it was the Moon’s gravitation force that did the trick.

NPS / Kat Gardiner

NPS / Kat Gardiner

Over time, the Earth’s wobble became more controlled and predictable, and that is why today, at Acadia National Park, we have such incredible animals as loons, beavers, and sea stars roaming the Earth’s surface. Because of the Moon, the Earth was no longer alone.

A Little Reminder about Evolution

All those animals didn’t arrive at once! Life on the planet developed slowly from microscopic to multicellular creatures

NPS / Kat Gardiner

The Moon now orbits around the Earth in what leading experts call “synchronous rotation.” In other words, the Moon rotates around its axis once in the same time it takes to revolve around the Earth once. This span of time is about 27 days. The Moon says this was done on purpose, in order to always face the Earth. It would be hard to have a conversation with your back turned towards someone, after all.

The Long-Term Prognosis of the Earth and Moon Romance

However, the Moon and the Earth are not completely synchronized. The Earth still rotates slightly faster than the Moon. This manifests as the Earth tugging the Moon along, like when someone is holding your hand and running faster than you. The force of this tug sends the Moon further out on its orbit, so every year the Moon separates away from the Earth by a few centimeters. Maybe the Moon will finally make that appointment in the other solar system one day after all.