If the universe is so big, where is everyone?

The answer

The Fermi Paradox highlights the contradiction between the high probability of extraterrestrial civilizations (given billions of habitable planets in our galaxy alone) and the complete absence of evidence for or contact with such civilizations. Proposed solutions range from the 'Great Filter' (a catastrophic barrier that prevents civilizations from advancing), to the 'Zoo Hypothesis' (advanced civilizations deliberately avoid contact), to the simple vastness of space making detection improbable. Some argue we are looking for the wrong signals, while others suggest advanced civilizations may have transcended physical form. The paradox remains one of the most profound questions in science.