Radio waves travel at the speed of light; it takes 1¼ seconds to cover Earth-Moon distance. It is the reason in the Apollo missions after Houston says something, the response from the astronauts on the Moon will arrive only after 2½ seconds.
Some presentations of the Apollo missions are edited to cut out the gaps created by the delay, and flat-Earthers use them to dismiss the Apollo missions as fake. However, in the actual audio recordings and the transcripts, the delays are there.
Some documentary edited the recordings. They removed the gaps to keep the narrative flowing. To observe the delay, we need to see the original recordings from NASA or various TV stations, like CBS or ABC.
Another misconception source is the lack of delay after statements from the astronaut and the responses from Houston. The recordings were done on Earth, and therefore, everything said by the astronaut in the recordings was actually said 1¼ seconds in the past on the Moon. Delays only occur in reverse. Everything said by Houston needs 1¼ seconds to arrive at the Moon, and the answer by the astronauts will need another 1¼ seconds to reach Houston. As a result, there will be a delay of at least 2½ seconds between Houston’s statement and the response from the astronauts.
There are also cases where the answer from the astronauts arrives earlier than 2½ seconds after Houston. It can occur if the astronaut responded before Houston finish its statements. However, these cases are not often, and the more than 2½ seconds of communication delay can be easily observed.
- Apollo 11 Mission Audio – Day 5 – NASA
- Technical Air-to-Ground Voice Transmission (GOSS NET 1) from the Apollo 11 mission – NASA
- Apollo 11 Spacelog
- Why is there no delay in the Apollo communications? – Moon Hoax: Debunked
- Why wasn’t there a communication delay when Neil Armstrong landed on the moon? – Space Exploration Stack Exchange
- Why did there seem to be no delay in communication between Mission Control and Apollo astronauts on the moon? – Quora
- Why is there no delay in the radio signal between the astronauts and Houston whilst on the moon during the ‘live feed’ (Armstrong and Aldrin 1969, Apollo 11) when, halfway on their way to the moon there was a delay of 4 seconds? – Quora
- Apollo 11 Part 26 CBS News Coverage of The Moon Landing – CBS News
- Apollo 11 As It Happened Live On ABC, Moon Landing And Moonwalk – 07/20/1969 Part 2 – Deep Space TV