Astronomy
Detecting Technosignatures Beyond Radio
Quick fact
Some optical telescopes can detect laser pulses so brief that they last just a billionth of a second—and if they are repeated in a pattern, they could indicate an artificial source.
Why this is interesting
When we listen for aliens, we usually think of radio signals. But what if advanced civilizations beam messages with lasers, build megastructures around stars, or leave metallic artifacts in space?