KUALA LUMPUR, Feb 15 — Malaysia’s first astronaut or Angkasawan, Datuk Dr Sheikh Muszaphar Shukor Sheikh Mustapha, took to social media today to debunk a ludicrous challenge by a "nasyid” singer who demanded proof that the Earth is not flat.

In an Instagram post, Dr Sheikh Muszaphar said his observations of our home planet are, quite predictably, contrary to what flat Earth conspiracy theorists preach.

"I went around the Earth 16 times a day. Every 45 minutes the Sun would rise and fall.

"I circled the orbit at a speed of 27,000 km/h,” he wrote.

He related how seeing the Earth with his own eyes evoked a spiritual experience, giving him shivers and making him breathless.

Suhaimi Saad, the singer who issued the challenge to the astronaut, had previously been discussing flat Earth theories on his Facebook page which led to a barrage of negative responses from Malaysian social media users.

"If he is brave enough to swear on it, I will stop this experiment and start preaching to flat Earth believers so they will understand things better,” he wrote, referring Dr Sheikh Muszaphar.

Dr Sheikh Muszaphar admitted it is difficult to change the minds of flat Earth believers but it would not stop him from sharing his own experiences with the public.

The 46-year-old was the first Malaysian to blast off into space under the Angkasawan programme in 2007.

According to him, it is hard to articulate what it feels like to be in space, but he explained that the Earth in indeed spherical.

"A geosphere, to be exact. Squashed at the poles and bulging at the Equator.

"Not like a ball but more to an egg [in shape],” he wrote.

However, Dr Sheikh Muszaphar’s scientific explanation appeared to go over Suhaimi’s head.

"Last week, Dr said that the Earth was spherical. This morning, you say it’s not really spherical but more like an egg?

"Are you for real? People online and Malaysians had such high hopes for you to say the Earth is shaped like a sphere,” wrote Suhaimi.

As with the astronaut’s explanation, a sphere is the simplest model of the Earth’s shape. The planet is not a perfect sphere with the radius varying between 6,353km and 6,384km. No perfect sphere can be found in nature.

The former member of nasyid group In-Team is known for conspiracy theories and getting into fiery debates with other users on his Facebook page.

In 2016, he proudly aligned himself with the anti-vaccination movement and said that none of his four children had been immunised against deadly diseases nor did they take clinical medicine.