A NASA satellite launched in 1976 carries a Carl Sagan–designed plaque sealed inside its core, mapping Earth’s continents 268 million years ago, at launch, and 8.4 million years from now — and that last date is no accident, because it’s roughly when the satellite is expected to fall back to Earth and finally be opened.
On 4 May 1976, NASA launched a satellite called LAGEOS-1 from Vandenberg Air Force Base in California. It…
