The search for extraterrestrial intelligence
The question has haunted humanity for centuries. With an estimated 100–400 billion stars in the Milky Way alone, and trillions of planets in the observable universe, many scientists believe the probability of extraterrestrial life is high. The Drake Equation, formulated by Frank Drake in 1961, attempts to estimate the number of active, communicative extraterrestrial civilizations in our galaxy. Depending on assumptions, estimates range from a handful to millions. The Fermi Paradox asks: if the universe is teeming with life, why haven't we found any?
In recent years, the topic of Unidentified Flying Objects (UFOs) has moved from fringe culture to mainstream legitimacy. In 2021, the U.S. Office of the Director of National Intelligence released a report on Unidentified Aerial Phenomena (UAPs), confirming 143 cases that remain unexplained. The Pentagon's All-domain Anomaly Resolution Office (AARO) continues to investigate. Notable cases include the 2004 USS Nimitz encounter (the 'Tic Tac' UFO), the 2014–2015 USS Theodore Roosevelt incidents, and declassified videos showing objects with flight characteristics beyond known human technology.
The Search for Extraterrestrial Intelligence (SETI) uses radio telescopes to scan the cosmos for artificial signals. The Wow! Signal of 1977 — a 72-second narrowband radio signal from the direction of Sagittarius — remains the most famous candidate, though it was never detected again. Modern SETI employs machine learning and massive array telescopes to analyze billions of frequency channels. Meanwhile, exoplanet discoveries have exploded: thousands of confirmed planets, many in the habitable zone of their stars. Missions like James Webb Space Telescope analyze atmospheres for biosignatures like oxygen, methane, and water vapor.