Neil Armstrong's Footprints on the Moon Will Remain There for 100 Million Years

On July 20, 1969, Neil Armstrong stepped off the lunar module and pressed his boot into the dust of the Sea of Tranquility. That single footprint is still there — and will remain almost exactly as he left it for an unimaginable span of time.

The Moon has no atmosphere, no liquid water, no wind, and no biological activity. There is nothing to erode footprints except micrometeorite impacts, which strike very rarely. Estimates suggest the prints will remain visible for 10 to 100 million years before being gradually obscured by space dust accumulation.

What Else Was Left Behind

• 96 bags of human waste from the Apollo missions
• The lower stages of every lunar lander
• Soviet probes including Luna 2 (the first object to land on another world)
• Multiple American flags (now bleached white by UV radiation)
• A retroreflector still being used today to measure Earth-Moon distance to millimeter precision
• Falcon feather and a hammer (Apollo 15) used to demonstrate Galileo's law of falling bodies

A Lasting Legacy

When humans return to the Moon in coming decades, the Apollo sites will likely be preserved as historical monuments. They are some of the only physical traces of the 20th century that may outlast civilization itself.