Voyager's Golden Record: A Billion-Year Message With Built-In Uranium Clock

In 1977, humanity launched two golden records into the interstellar dark — not merely as greetings, but as a philosophical wager that the laws of physics are universal enough to bridge civilizations separated by billions of years. Embedded in each record's cover is a sample of uranium-235, a radioactive clock requiring no power and no shared language, only the understanding of decay that any spacefaring intelligence would possess. The Voyager Golden Records are perhaps the most ambitious act of communication in human history: a message designed to outlast every institution, every language, and