Many years from now humanity will face a law suit. Humanity will be charged with polluting the galaxy with organic life.
Once humans make the permanent move into space they will choose to inoculate almost every celestial body that they come across with the chemical building blocks of life. Over thousands of years humanity watches life grow and evolve. Each time life develops in surprisingly different ways in even the most hostile environments as long as it has the few necessary components.
Of course, life forms that are far older than humans know the detriment that overpopulation can have on a galaxy. Humanity is kindly asked to cease and desist, but to no avail. Ancient organic and synthetic life forms banish humanity to the dark space until the time of the hearing.
During this interim, some of humanity’s biology experiments learn to create matter and energy without producing harmful byproducts. This negates the charges of threatening galactic harmony that humanity faces, which is a major embarrassment for the court.
Grudgingly, humanity, that infantile race, is allowed to return.
The Lunar Fox Press 