The Earth's own ecosystem filters out unsuitable species
So, what about the universe?
In 2012, alien civilization came to Earth, and using normal interstellar transactions as a means of diplomacy, the alien civilization used a new energy source [black sun] to trade various metals and resources with humans.
In 2013, black sun energy was parasitic and polluted around the world. After research by scientists from many countries, it was discovered that the essence of black sun is a special parasitic life of pure metal.
In 2014, human beings exploited black sun energy in various places, causing black sun to spread across the earth. A large number of animals and plants died because they lost their ability to adapt to the environment.
In 2015, alien civilization clearly revealed their true purpose, which was to invade the planet. Within a few days, they took over the government and management of human civilization. Countries responded quickly to form rebel armies, but most of them were wiped out under the attack of alien armies with black sun energy. Human civilization is forcibly controlled by alien civilization, and alien civilization colonizes the earth in large numbers.
In 2018, the black sun officially covered 99% of the world's land and oceans. A large amount of soil was contaminated by the black sun and turned into a hotbed for the black sun. The entire planet's natural environment quickly disappeared, and the entire planet turned into a colonial star with a dark appearance covered with black metal substances.
In 2020, cities in various countries on the earth are expanding, and urban areas account for more than 45% of the entire planet. The status of every human being has become very low. Because humans no longer need productivity, mechanization, and 100% recycling of survival materials, more than half of humans live in a state of drunkenness and dreaming every day.
Concept: The story of humankind uniting to fight against alien invasion