The Doomsday Asteroid (What Little Remains)

The Doomsday Asteroid, also called The Asteroid or the Rock of Death, was an asteroid 11 kilometers wide and 9 kilometers high. This asteroid is the only recorded asteroid to impact Earth, and it led to the Sixth Mass Extinction (which brought the extinction of animals such as cheetahs, elephants and pandas, which were already in danger of extinction at the time of the Doomsday Asteroid), as well as the fall of pre-Asteroid civilization.

Structure
The Doomsday Asteroid measured 11 kilometers across and 9 kilometers in height. It had an oblong shape and boasted two craters. From the remaining fragments scattered across the US East Coast, scientists determine that it was a nickel-iron asteroid, with approximately 80% of its structure being composed of various metals and the rest of rock.

Timeline of the Impact
When NASA announced that the Doomsday Asteroid was coming for Earth back in September 12, 2037, a Great Panic insued. Crime rates, as well as murder and suicide rates, spiked dramatically. Law and order broke down and gave way to anarchy almost worldwide, as people thought it was the end of the world (it was the end of pre-Asteroid civilization) and so resorted either to divine intercession or immoral acts of debauchery. Companies started manufacturing bunkers, and markets and malls were stripped clean of basic supplies like food, water, and clothing.

On November 16, NASA officially released the date and time of impact. December 22, 7:43 AM EST was when the asteroid would hit. NASA also released a statement saying that the asteroid'a trajectory would result in an 80% probability for impact on the coasts of the Western Atlantic.

NASA's predictions were to be almost completely true. At 7:43 AM EST, on December 22, 2037, the Asteroid made impact on the South Carolina-Georgia border. The impact was thousands, perhaps millions of times greater than the Hiroshima bomb. From Jacksonville, Florida to Charleston, South Carolina, the land gave way to a crater, which, in due time, was filled by the encroaching waves of the Atlantic. Every living thing for miles around had been killed. Ash caused fires in places as far apart as France and China, soot blocked the sun, the tectonic plates began to move violently, causing worldwide earthquakes, the likes of which had never been witnessed by human eyes, and the shockwave emitted by the impact circled the world three times over, obliterating every single above ground structure that humans had ever built, and killing billions upon billions of organisms. In just 6 hours, the forces of the universe removed what had taken 200,000 years of Homo sapiens to build. The old world was gone.

Ramifications for Humanity
The Asteroid forced humanity to build a new civilization from nothing but the ruins of the old and the minds of geniuses. 6.8 billion people died in what would be known as the most cataclysmic event in pre-galactic human history. The surviving 1.6 billion were booted back to the Stone Age. However, after hundreds of years of rebuilding and reshaping society, humanity was restored to what it was just before Impact.

The Asteroid also changed the geography of the North American Continent. The crater left behind by the Asteroid covers parts of South Carolina, Georgia and Florida. With these lands now a few hundred meters below sea level, the waves of the Atlantic came rushing in, creating what we now know as Crater Gulf. It also raised up much of Georgia and South Carolina, thus cutting the American East into three regions: the Coast, Florida, and the inland areas, separated by the Appalachian and Ring Mountains.

The Asteroid also scattered many precious metals like gold and silver into Earth's crust, creating huge gold and silver veins in the Ring Mountains.