The universe is 13.8 billions years old. The Earth formed 4.5 billion years ago. Life miraculously came into existence 3.8 billion years ago. Our star and planet are relatively young; scientists have discovered a planet at least 12.7 billion years old. If an older planet had life, a technological extraterrestrial civilization could have left their star system as much as 8.2 billion years ago. Using technology that we know is possible, an alien civilization could have colonized the entire galaxy in as few as 4.5 million years. The Drake equation attempts to predict the number of technological extraterrestrial civilizations that we could detect. However, most of the variables are not known, so it’s predictions are essentially wild guesses. Some scientists think there could be millions of ETs and even if life is extremely rare, and there are only four civilizations, the chances are they got a billion year head start. The question is, where are the aliens? This is known as the Fermi Paradox, which has a bunch of hypotheses that attempt to explain the lack of detectable ETs. One of the hypotheses is called the Zoo Hypothesis and it suggests that the entire galaxy is occupied and the ETs are deliberately hiding. They could have created life on Earth 3.5 billion years ago as a billion year experiment on evolution. We could be an ET’s equivalent to the Nature channel.

For my universe, Fractal Federation colonizes 1400 star systems within a 50 lightyear radius. I haven’t decided whether I will introduce ETs or not. Fractal Federation banned Active SETI, which broadcasts signals that could be detected by an alien civilization, giving away our position. I don’t believe a civilization will have the same morality just because they are technologically advance.

Wikipedia – Drake equation

Wikipedia – Fermi paradox

I created a spreadsheet with the Drake equation and my own equation. My equation, the variables aren’t known, so it’s no more reliable than the Drake equation but it does give you a better idea of the fact that even if life is extremely rare, an alien civilization would have had enough time to colonize the entire galaxy.

Google Sheets – Alien Calculator