No one doubts that the biggest achievement of the July 20, 1969, lunar landing was simply getting there. It was a monumental triumph of will — and technology. Yet once Neil Armstrong took that historic step, the point of the mission switched: Armstrong and fellow astronaut Buzz Aldrin set out to further man’s understanding of the moon itself.
They, and subsequent Apollo visits, delivered. Lunar science has been expanding ever since.
For two and a half hours during their extravehicular excursion, Aldrin and Armstrong romped around the Sea of Tranquility, installing equipment and collecting precious cargo: 50 pounds of lunar rocks. Those samples would be studied for decades.
What have we learned? Before Apollo 11 brought those rocks home, we knew few basic facts about the moon, facts Google could quickly answer today. How old is it? We now know it’s about 4.5 billion years old. How far away? Thanks to Apollo 11’s laser-ranging experiment, we know its distance down to the inch at any moment.