" We are born from the universe and to the universe we will return " said an unknown philosopher from unknown times.
The Human Empire was the manifestation of the hopes and dreams of the human species as they looked into the bright night sky and wondered of the beyond. Novelists wrote stories and thinkers thought theories on the origin of everything and what was to be found on the other side of the un-crossable river. And as they grew and had children and their children had children of their own they tried to build boats to cross the river.
" One small step for man, one giant leap for humankind " said a nondescript traveler from humanity's infancy. They loaded their ambitions into steel structures and sent them beyond the exosphere.
They reached the ivory world of mythology, the Moon and inhabited the satellite, transforming the barren rock into a green and blue pearl reminiscent of their homeworld next door. They set their eyes on the celestial bodies seen by their ancestors and soon set their legs too.
Yet, as soon as they landed on these worlds faraway, the issues of the Human Empire and the causes of its eventual downfall would become clear. Scientists from the times of ignorance had long since pointed to the sheer insignificance of light speed in the scale of the observable universe and communications between the settlements of the Empire took hours, and when it had truly reached its peak, days and years.
When humans had conquered their home star and set their sights for their beyond, they were met with yet another challenge. The energy required to send matter to the new horizons was astronomical. Humanity went on and with the promise of infinite resources at bay hacking into the greed of the human psyche, the space industry boomed and they built Dyson spheres and other such megastructures to extract every Watt of energy from their star.
Thousands of years earlier, the mythological figure and greatest monarch of Mesopotamia, Gilgamesh had by that times discovered that humanity's greatest weakness was not its greed or lust but it's own mortality. By the time philosophical discussions about man's limited time in the mortal plane had sprung up again due to the ethical concerns of long space travel durations, humans already enjoyed a few hundred years of life, and most of it healthy at that, due to numerous advances in medical and anti-aging technology. Yet, travel times were often equally as long.
Humanity's solution for this was controversial, through putting humans in a suspended state of animation through cryogenic technology for the duration of the trip, these issues were eliminated(omitted). Cosmonauts, as they were now called, left everything: their families, their friends, their worldly possessions all behind in order to spend hundreds of years in a sleep state and knowing it's not even guaranteed they'll make it to their destinations alive.
The perigee of the Empire came about through the conquest of the galaxy, and soon, most of it had been conquered by the humans, though the term 'humanity' to refer to a single species had been used only in name for quite a while, as hundreds of years of physical and temporal separation had created millions of species within the Homo genus. Some evolved wings, others evolved fins. Some evolved short height, others were of towering height. 'Humanity' was all over the place and differences make for a good pretext for conflict.
For a while, though just the precursor to a storm, it would be a good time, a Golden Age, if you will. Humans lived thousands of years in relative peace and good health, they built space-scrapers, they changed climate and nature to their will, and they sang songs of glory and unity and prosperity for all and built their children in the form of intelligent machines that would care for them for eternity.
As aforementioned however, the peace didn't last long.
On an unknown date, a certain planet from a certain planetary union refused to disclose their discovery of deposits of elements used for lucrative industries to another planet in the same planetary union. They went to war.
These 2 planets didn't maintain a multilaterally equal relationship and the former planet planned to use these resources as a catalyst to change the dynamic of power within the planetary union. The latter, much more powerful planet, saw this as a betrayal and engineered a propaganda war preceding their real attack; They accused the planet of treason of the Empire's values of 'Prosperity for all', a grave sin among their contemporaries and even accused them of colluding and interbreeding with non-human enemies, a fallacy considering the lack of evidence for other enlightened life in the Empire.
They thus caused calamity to the other planet. Wars in the galactic age, unlike depictions of it in the times of ignorance, did not involve loud machinery and explosives and warships and space jets. To 'punish' the weaker planet, the regional hegemon simply sent cultures of fast-growing bacteria that synthesized dioxygen into carbon dioxide, and watched as the natives, which evolved surrounded by air with very high oxygen concentration, died off and the planet becoming a silent place, testament to the emptiness and massacre comitted.
From there on it was a sloping hill for the Human Empire. they waged war and killed and enslaved countless, the wisdom of good governance forgotten, and the values on which the Empire was built, omitted and stained.
In the midst of it all, one technology would bring back hope for change, and although not enough to mend the cracks of the Empire, cracks which it was born with, it would surely bring about a new age and ways of human life, and with it, countless philosophical discourse on it's nature.