Astronaut-minister explains moon landings to Iker Casillas

So far, the goalkeeper – who is now based in Oporto, Portugal – has received over 310,000 replies after launching a straw poll on his social media site.

Duque, who became every school child's hero in 2003 when footage of him floating in zero gravity graced their TV screens, added his own reply.

“The facts won't change, whatever people believe,” wrote the minister, who spent 19 days in space, of which 10 were on board the International Space Station.

“The apparatus they took with them, the footprints, the laser reflectors will still always be there. The photo which awakened the sense of conservation of the earth will continue to exist.”

He uploaded a link to NASA showing the picture taken of the earth from the moon.

The minister's long career as an aeronautical engineer and his countless academic research reports on space, as well as his comments on Twitter, were finally enough to convince Casillas.

In response to the former spaceman, whose Twitter username is @astro_duque, the footballer wrote: “Behind each and every one of us is a person. Hands up those who have never got it wrong at least once. Learning from our errors makes us stronger, and accepting them makes us more human.” He included the hashtag #YoTambiénFallo ('I also make mistakes').

But it appears a high number of Twitter users make mistakes – a huge number of Casillas' followers who replied cited conspiracy theories.