The Consequences of Earth Losing its Celestial Partner

It's rather difficult to look up at the night sky and not see the Moon. It is by far the most salient object circling our Earth. But, have you ever wondered where it came from? What its purpose is? And what would happen if we were to lose it? Mankind has been wondering about these questions for thousands of years. We have only recently began to understand what our celestial partner means to us.

In order to fully understand the Moon, we would necessarily start by asking – where did it come from? There have been several theories spanning many decades. Earlier versions of lunar formation theory included capture, whereby the Moon would have been a captured planetoid. Another theory was fission, where the earth was spinning so fast that it would have, quite literally, belched it out of itself to cool and form away from us. It is in fact this latter theory that led us to the one we currently espouse to, that is to say, the giant impact theory. According to this, there occurred a collision during the late stages of planetary formation in our solar system. At that point, planets were still very new and busy forming. It was at this time when Earth was just an embryo – a baby planet, when a collision would have occurred with Theia, a Mars-sized planetoid. This collision ripped apart early Earth's crust and that crust then coalesced. It snowballed into a whole separate entity, which we now call the Moon.

Every 27.3 days, the moon makes its way around our planet while also completing one turn on its axis. Known as synchronous rotation, this celestial dance means that the same lunar face always peers down at us. Viewed from Earth, the amount of the moon illuminated by the sun appears to wax and wane, creating the familiar cycle from new moon to crescent to full. This sequence is a combined result of the moon’s changing position relative to both the Earth and sun, requiring 29.5 days to complete one full lunar cycle. Even though the same side of the moon always faces Earth, there’s no true “dark side,” as many mistakenly call our lunar orb’s far side. Even the far side of the moon receives sunlight — we just can’t see it — and the section of the moon illuminated on any given day shifts depending on the moon’s position.