'The Butterfly Effect' is an idea that said a small change of a complex system can lead to a great impact. The term comes from Ray Bradbury's 1952 science fiction story 'A Sound of Thunder', a character use a time machine to travel back in the past where he stepped on a butterfly. After coming back to the present world, he found a fully different world than before. A simple change in the past can change the future drastically according to the 'Butterfly Effect'.But physicist Sinitsyn & his colleague Bin Yan proved that there is no Butterfly Effect in the quantum realm.
To test the butterfly effect in the quantum system, they used a complex IBM-Q quantum system where they slightly changed things by applying some quantum gates, with forwards & backward cause & effect. They found that the local information didn't damage by the minor tampering in the system. The experiment proves that the butterfly effect doesn't apply in the quantum realm & if we changed minor things in the past, it won't affect that much in the future. Nature has its own way to heal herself from minor tempering.
The Fermi paradox seeks the answer to the question of where the aliens are. The Fermi paradox was named after the Italian physicist Enrico Fermi, who is famous for creating the first nuclear reactor. The Fermi paradox is the apparent contradiction between the lack of evidence for extraterrestrial civilizations.
Like many stars, as there are in our galaxy (100 – 400 billion), there is roughly an equal number of galaxies in the observable universe. For every star, there is a whole galaxy out there. As many as 6 billion Earth-like planets in the Milky Way galaxy. Enrico Fermi also estimated that there should be 10,000,000,000,000,000 intelligent civilizations in the observable universe. The answer to the Fermi paradox is unknown. The scientists could do is "possible explanations".