China’s first astronaut, Yang Liwei, returned from a 2003 mission reporting a mysterious ‘knocking sound’ in space that still puzzles scientists.
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The Taikonaut launched aboard Shenzhou 5 twenty-three years ago for a 21-hour mission that would see him orbit the planet 14 times before touching down safely in Mongolia.
While in space, Yang heard something outside his capsule that left him confused - a sharp ‘knocking’ sound over and over again.
“He examined the capsule, looked out the porthole, and inspected the panels, but couldn’t identify its source, even as the sound persisted.
He maintained it was not emanating from the inside of the capsule but from the outside, in the vacuum of space, where, in theory, sound shouldn’t travel at all."
Despite thorough inspections afterward, the source of the sound, which resembled someone hitting the hull, remained elusive.
Subsequent missions also reported the same phenomenon, sparking various theories, including micro-debris strikes and thermal cracks.
With no definitive answer yet, Yang’s ‘knock-knock’ in space remains an intriguing unsolved mystery.
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