During Mercury's Pre-Terraformed history, it was not a physically impressive planet, but despite that, it has stood as one of the most culturally significant worlds throughout the whole of Human history, as it was visible to their naked eye throughout the entire species' existence. Its name derives from the Roman mythological messenger god. And it has certainly lived up to its name, as it served as the metaphoric harbinger to humanities evolution from a type one to a type two species, allowing the complete control of all energy outputted from their parent star of Sol through the use of a Dyson Swarm.
Thanks to this, Mercury was one of the most important and populace worlds of the Sol System during humanity's early interstellar period, with a population of around five billion individuals during this time. In fact, many who live there have petitioned for the terraforming of the world, as well as placing it in orbit around its sister-world of Venus, however due to the importance of collecting the energy gathered by the respective Dyson Swarm in orbit around the sun, and Mercury's perfect position from the aforementioned star, these have been denied.
For many years, humans had pondered the strange layout of their home star system compared to many other star systems in the Milky Way, as it seemed to stand out in the lack of gas giant worlds in close proximity to the parent star of the system. And thanks to this, many had theorized that Mercury was the former core of a once large gas giant that thanks to its close proximity to the star, had the gases that made up its being slowly burned away, also known as a: "Chthonian Planet." Upon analyzing ancient rocks that are on the surface, humans are now fairly certain that this is the case, due to evidence of extreme pressures being placed on the aforementioned rocks that were mostly likely caused by massive amounts of gasses surrounding it at one point.
Mercury was moved out of its original orbit in 4511 CE to aid in the completion of the terraforming of Venus. This caught the attention of a couple massive corporations back on Earth who sent out teams of their own to begin terraforming procedures on Mercury as well. Terraforming began in 4555.
Gases collected from Saturn, Uranus, Neptune, and a few of their moons were imported to help create a new atmosphere. Over the next five hundred years small plants and animals were slowly introduced. By 5123 Mercury had been completely terraformed.
Mercury's geography before human colonization was primarily comprised of hot rocky plains and massive razor sharp dust fields. Across the planet are also countless ancient craters, as the planet lacked an atmosphere throughout its entire history, allowing any and all asteroids to collide with the surface unabated.
Once humans arrived, a large part of the planet would be urbanized, with a select few massive cities built across the planet's respective poles. Along with the urbanization, much of the planet's overall size has actually shrunk, as much of the planet has been used in the creation of the Dyson Swarm
Now, as a moon of Venus, Mercury's geography comprised primarily of lush jungles, temperate deserts, and vast oceans. Its idyllic landscape has made the world a very popular tourist destination from extra-stellar travelers to the Sol System, making the moon almost like a giant hotel world.
Due to the planet's close proximity to Sol, it mostly experiences a very hot climate, with an average global temperature of around one hundred and thirty-six degrees Celsius, making it very inhospitable to Earth life. Along with the temperature itself, it also is inflicted with massive amounts of stellar radiation, contributing to the inhospitable nature.
However thanks to the lack of an atmosphere it does not retain any of the heat generated by its parent star, so during the planetary night, the temperature drops sharply, giving an average temperature of minus two hundred and ninety degrees Celsius.
Mercury's population is extremely large for both the size of the moon, and the original class of world being very foreign to Humans. But thanks to its importance in the Sol System, many have chosen to live there due to the massive amount of job opportunities on the planet.
Almost the entirety of the planet's population is Human thanks to it existing in their native star system. And this aforementioned population almost entirely lives on the four major cities located across the planet's north and south poles, Hermes, Agni, Isimud, and Malakbel. These cities are fairly large, spanning thousands of kilometres in diameter and are all named after various messenger gods in human mythologies.
As with Venus, some of the ancestors of the current inhabitants of Mercury came from the equatorial regions of Earth, but surprisingly most came from Venus. Mercurians, while having darker skin like Venusians, are also taller and weaker due to moon's weaker gravity. Also because of the weaker pull, many inhabitants have opted for genetic engineering and have implanted wings onto their person, allowing them to fly around. This has led to genetic incompatibility with baseline humans and other complications.
As the planet's original overall function is solely based around the collection of the power gathered by the Dyson Swarm in orbit around the sun, the culture of the populace reflected that. Almost all of the planet's job force is based on the management of the swarm, as well as the mining of precious resources on Mercury.
Along with the collection of energy, the former planet use to experience a worldwide aurora during the night, leading it to be a very popular tourist destination of the Sol System as it is the only world in the system that experiences this affect.
Now, the culture of Mercury is almost an exact mirror image of the other worlds of the Sol System, losing most of the former uniqueness it once had. As a result, the moon has a fairly weak cultural identity, almost existing as a province extension to planet Venus.
The planet that we would know as Mercury began to form when the an ancient massive gas giant planet that formed in close proximity to the star Sol began to have the gasses that made up its composition slowly burned away in 4,571,000,000 BCE. This process only lasted around one million standard years, and at its apotheoses, it would leave behind the now barren iron rich core, becoming the planet Mercury. Eventually, the planet, due to it being in close proximity to Sol, became almost tidally locked to its parent star.
After its creation, it would experience countless asteroid impacts throughout billions of standard years, as many asteroids heading for the sun proper would have their trajectory perturbed by Mercury's gravity, ultimately leading them on an collision course to the small planet.
Humans would have a deep fascination with planet Mercury for thousands of standard years, and once they reached the early space age, they were unable to visit the world due to its close proximity to the sun, as well as its inhospitable nature, locking them away from studying the planet. Thanks to advancements in space technology, humans were finally able to reach the planet in 1,973 CE, with the Mariner 10 probe. Afterwards further probes were launched towards the planet, however due to the extreme gravity of the sun, they found it very difficult for several decades.
During humanity's expansion throughout the Sol System, the first Mercurian colony would be established in 2,145 CE. This colony would be known as: "Hermes," in honor of the planet it stood on, and it would have a fairly small population of around three hundred.
Hermes would serve as the only colony on the world for several standard years, until' the construction of the Sol Dyson Swarm began in 2,150 CE. As the planet was stripped mined away, more and more people would make their home on Mercury, constructing the more large cities to accommodate them. And upon the swarm's completion in 2,278 CE, Mercury would have a population of around five billion.
For the next two thousand years, Mercury was not just used as a base to study Sol and the galaxy, but it was also mined due to its natural resources.
Mining operations were heavily scaled back when Terragen began to move Mercury out to be placed into orbit of Venus. Mining resumed when terraforming was complete but the resources mined were used to construct new cities and towns.
Mercury is currently a thriving world with a native Mercurian population of around one trillion individuals.