It’s officially been 50 years since a couple of people forever changed the course of human history.

Today is the 50th anniversary of the Apollo 11 launch, which became a pivotal moment in history for the future of space exploration and humankind.

The official launch time of Apollo 11 was at 8:32 AM EST on July 16, 1969. It was this mission that put humans on the moon for the first time ever.

Neil Armstrong and Buzz Aldrin walked on the moon four days later on July 20, 1969, with Armstrong relaying the now-famous line, “One small step for man, one giant leap for mankind.”

The state of Colorado has had a huge influence on the space industry. One of the experiments left behind by the astronauts was created by a Colorado University professor.

Dr. Jim Faller is a scientist and physics professor at the University of Colorado and his experiment still operates on the moon. Scientists and Dr. Faller’s lunar retro reflector is still being used today.

“Over 50 years, it’s gone from, let’s say 100% transmission to 10% transmission,” said Dr. Faller. “Lasers have become brighter, so that makes up for that.”

The success of his experiment has helped astrophysicists improve and advance GPS technology.

Coincidentally, tonight also happens to be a total lunar eclipse, which is set to take place at 5:30 PM EST. Total lunar eclipses are a slightly rare event, happening just a bit more frequently than twice every three years.