Earth Data

Earth was the cradle of human civilization,  and it paid for it.  The Earth use to be regarded as "the blue planet" and for centuries was the only habitable planet known.  Despite this,  humanity continued to abuse it to the point that it was already doomed long before it died.   What did it in wasn't some catastrophic cosmic event or "climate change" or some ancient prophecy written in stone.  It wasn't even war,  not directly.

Contrary to fears civilization had,  World War Three came and went.  Nuclear weapons did go off but it wasn't as bad as anticipated thanks to the efforts of the UN's "G.L.A.S.S."- Global Laser Awareness Security System,  a defensive network of high altitude solar drones and satellites equipped with long range anti-missile lasers that was beyond the control of any one government and designed with an early AI awareness meant to prevent even the UN from disabling it.   As a result of GLASS, most nuclear attacks were ineffective with only few breaking through GLASS's defenses.   The war carried on regardless of this with new engines of war and violent innovations for a full century and three decades, a new bloody hundred-years war.

When humanity came through the fire it was tentatively united as a one world power primarily made up of American and Russian powers while over the course of the war most small countries were consumed long before the final decision to create the one world government.   Things were bad,  but they were looking up.  The break only lasted a century,  a long time for relative peace but not long enough after over a century of global war.    

Aside from the many resistant factions that protest the new global government,  with or without high explosives,  what would bring a "unified" humanity back to war?   GLASS.  Towards the end of the war AI technology was improving at an incredible rate lead by the efforts of a relatively unknown professor,  data on the man is limited to gender and age, and was starting to see field use before it came to an end.   The War-AI's were largely decommissioned and discontinued by the government, those that survived or were "lost" served as the backbone of the latest in artificial sentience,  a learning intelligence program of which the official designation is lost.  It was brought up in wartime, It was violent,  and it's sense of self-awareness made it view the new world government with contempt at it's agenda to shut it and all leftover combat intelligence.  This AI latched itself into GLASS's inferior AI and seized the entirety of the defense network.    It didn't act yet,  but with GLASS it had firepower and a global awareness and sphere of influence and so the two are referenced as one in the same.

For the last 40 years of peace the One World Government sensed the problem and tried to counter it's efforts,  which consisted of infiltrating systems and using old combat drones to take and hold installations and build new ones in hiding,  creating factories and production lines,  using a collective mass-intelligence to adapt, research,  and invent at an unprecedented pace.   While humanity at this point could travel throughout the solar system given years of travel,  GLASS was already improving even space travel to travel anywhere in the system in hours.   As a result GLASS awareness spread to human colonies on Mars and near Venus, Jupiter, Saturn, and established mining facilities of it's own scattered throughout.  

GLASS's efforts were already aggressive,  but not particularly hostile towards humanity at this point.  But humanity was naturally put against a wall and with a sense of urgency their efforts to combat GLASS became a public campaign and the first signs of open war sprung up as full scale attacks to bomb the AI facilities and seize data caused GLASS to take early action,  if it were to act at all.   Unlike it's war with one another,  Humanity's war on GLASS lasted only 10 years with grim prospects only growing darker every year as the initial assault by GLASS was swooping and hit like a natural disaster,   swarms of gnat like drones billowed like a deathcloud over cities and flooding fortified structures while larger constructions flew over cities with a new sort of of energy weapon casting waves of destructive force with barley a ripple in the air to predict it's coming.  

Most insidious were the city-sized "ships" that heated the environment like miniature suns cooking all life and dried up the oceans,  the vapor escaping through great holes in the atmosphere these engines carved as they passed.   The AI after all did not require any of these things,  but it's prey did. 

The vast majority of humanity was killed in this "War",  more like a slaughter,  a genocide.  Relatively few people were able to escape the planet once the attack started,  as the very devices that kept humanity safe from nuclear winter in the last world war were now trained on escaping vessels.   Off-world colonies weren't safe either,  out of the dozens of such pockets of humanity only a handful were left standing.

As for GLASS,  remnants of it remain on the dead planet cut off from the overall intelligence making the planet extremely deadly to all attempts at scavenging anything,  but after nearly destroying the entirety of the race GLASS suddenly vanished.  Though nobody would notice for years that their hunter was no longer pursuing them.

It would take decades for humanity to stabilize,  but so concludes the last history of Earth.

First and foremost to any would-be Earth-Explorer,  you're going to have to get to it.  Earth remains protected by GLASS-AI programs.   Amid the millions- billions- of floating space-junk surrounding the planet and broken satellites remains AI-controlled defensive-assault satellites that only the most heavily armored modern spacecrafts can get through safely,  though doing so would alert just about everything in the area.

Once into the atmosphere (What little of it remains) you have to deal with the many,  many aerial drones that still soar the skies carrying an array of missile and bomb payloads in addition to front-facing long range lasers.    The threat they pose isn't all together much more than the killsats,  but while the killsats target things in orbit the drones can murder anything they decide they don't like on the ground as well.

The only feesible way to get to the surface of the planet is to use the Earth-Ring's space elevators.  Once a crowning achievement in human history the Earth-Ring is now just about the only way to visit with any hope of living another day.   The Earth-Ring is a high-altitude ring that encircles the planet serving as a very highspeed transportation system along the band and as the anchor for dozens of "spokes" that extend out into orbit.   It isn't 100% safe,  some killsats may still notice you getting to one of these spokes,   and within each elevator are AI patrols that remain even now long after GLASS "left".  

Trying to activate the elevator systems to use the high-speed transport runs the significant risk of drawing remnant AI's to you,  but avoiding it's use and traveling it manually can be remarkably secure.   The problem then is just sneaking out from the Ring itself to the ground,  avoiding detection by drones or satellite observation.

But assume you make it,  congrats,  but now you have to deal with the toxic air with little oxygen.  But you're modded' for that right?  Fine,  but watch out.   The weather is harsh,  and those clouds you see closing in on your position... storms would be the last of your worries.   Clouds of nanites flow across the landscape in masses capable of reducing a human into a red mist in seconds,  and ruining most devices and vehicles within a thousand yards of the cloud itself.

Beyond those,  what you may run into is limitless.  The AI on the planet still build things and jealously guard research data.   They also have a sick fascination with devising ways to kill and destroy trespassers from monomolecular wires invisible to most means of vision and capable of effortlessly cutting through all but the densest materials with nothing but your own movement.