The dark side of the moon refers to the part of the moon that does not face the Earth. It was unknown until humans were able to send spacecraft around the Moon, so we could finally view this area. A new study suggests that our moon once had a smaller companion, but it was destroyed in a collision that left one side of the lunar orb lumpy. A primordial collision between two natural satellites of Earth could explain the stark differences between the moon’s two sides. Our moon is asymmetrical, exhibiting a mysterious dichotomy between the visible side and its remote far side and now scientists think that Earth once had two moons, which merged in a slow-motion collision that took several hours to complete. They feel the contrast between the two different sides can be explained by a collision with a sister moon about one-thirtieth the Moon’s mass, or around 1,000 kilometers in diameter.
On Oct. 7, 1959, the Soviet Luna 3 spacecraft looped behind the moon, snapping off a series of grainy but distinct photos and then radioing them home. Because the moon’s rotation is perfectly synchronized with its revolution, one hemisphere always points toward Earth while the other always points away, unseen. One theory speculated that the Moon has two different looking sides, because Earth’s gravity raised powerful tides on the moon billions of years ago, while it was young and molten. The bulges then froze in place, giving rise to the thicker crust and distinctive geology of the far side. This made things more complicated and thus it did not pass Occam’s razor or the law of simplicity, so it lead Erik Ian Asphaug the American- Norwegian planetary science professor to develop a low velocity impact theory and his Big Splat model.
In 1975, two groundbreaking papers discussed the Giant Impact theory, of how our moon was created. In this model, Earth was born moonless. Then shortly after its formation it collided violently with a Mars-size body, commonly referred to as Theia (the mother of the moon goddess Selene in Greek mythology). The resulting inferno vaporized Theia along with a substantial part of Earth’s outer layers. Some of the material was blasted to kingdom come, but much of it settled into a disk around the bruised Earth. Within a very short period of time, perhaps as little as a decade, the disk had condensed to form the moon. Research costs money and going back to the moon won’t break the bank, and Congress allocated over $20.7 billion to NASA in the 2018 omnibus spending bill, which was about $1.1 billion more than the agency got in the previous year’s omnibus bill. They have to keep their priorities straight which can be difficult and not become a spendthrift agency, or go to the other extreme and become a tightwad.
Establishing a permanent presence on and around the moon is the immediate aim, because it will allow NASA and its partners to push out even farther into the solar system, to Mars and beyond. I don’t see us holding a Frisbee throwing contest there, or setting up a hamburger franchise any time soon, but who knows how far man will reach. I am certain that one day a memorial will be established on the Moon to commemorate all of the astronauts and cosmonauts who have died in the space race.
Written for Sheryl’s Daily Word Prompt – Difficult, for the Daily Spur prompt – Dark, for FOWC with Fandango – Spendthrift, for Ragtag Community – View, for Paula’s Three Things Challenge – Memorial Hamburger Frisbee and for Word of the Day Challenge Prompt – Contest.