The moon is moving away from Earth at 3.8 centimeters per year — which means the total solar eclipses humans alive today get to see are something no future civilization will ever witness
Apollo 11 astronauts Buzz Aldrin and Neil Armstrong left a suitcase-sized array of corner-cube retroreflectors on the Sea of Tranquility in July 1969, and observatories on Earth have been firing lasers at that mirror — and three others positioned by later Apollo and Soviet Lunokhod missions — for greater than fifty years. The round-trip journey…