The search for extraterrestrial intelligence (SETI) excites our imagination. Yet many scientists argue that contacting aliens—the “active” side often called METI—could be risky. They urge caution until we have clear rules, broad consent, and a better grasp of the consequences.

Why contacting aliens might be dangerous

Stephen Hawking warned in 2010 that contact could resemble Columbus meeting Indigenous Americans—catastrophic for the less advanced side. His point still frames today’s debate. More recently, science writers and risk researchers have stressed that we don’t know ET’s motives, capabilities, or ethics; therefore, prudence and process should come first. Updated debate in 2024–2025 has revived these concerns as new telescopes and METI proposals gain attention.