Brian Cox laid into the rapper for his support of a theory claiming the Earth is not a sphere but rather is shaped like a disk.
Despite overwhelming evidence that Earth is a spherical globe-shape, a third of young people – including B.o.B. – believe that the Earth could be flat.
But the British physicist dismissed his claims, saying: “A ‘flat-earther’ is a person who thinks the Earth is flat, and that is not right.
“It’s a sphere.”
Leaving BBC Radio 1 presenter Greg James in stitches, Prof Cox continued: “To his credit – again, I’m not going to defend what he thinks. Its totally wrong – that’s the heart of science.
“If you want to prove something to yourself and you should do, that’s a good instinct, then that’s what you do.
“You get your money, build a rocket, go off into space and then you will find it’s spherical. He has wasted all his money but he will have learnt something.”
In 2016 B.o.B. shared his views on Twitter, writing: “I’m going up against the greatest liars in history … you’ve been tremendously deceived.
“A lot of people are turned off by the phrase ‘Flat Earth’ … but there’s no way u can see all the evidence and not know… grow up.
“No matter how high in elevation you are … the horizon is always eye level … sorry cadets … I didn’t wanna believe it either.”
A survey carried out by YouGov which polled 8,215 US adults found that 84 percent believe that the Earth is round.
But that figure falls to just 66 percent of 18 to 24-year olds, a generation known as millennials, who are convinced that the Earth is a globe.
In March 2018 self-proclaimed rocket scientist “Mad” Mike Hughes attempted to prove the Earth was flat by blasting himself 1,875 into the air with a homemade rocket.
Mr Hughes converted a mobile home into a ramp to launch vertically into the air at nearly 350mph before coming crashing down to Earth with a parachute.
Following the launch, he announced he would build a ‘Rockoon’ – a rocket carried into the atmosphere by a gas-filled balloon – that will take him about 68 miles above ground level.
He expects to fulfil this plan by August and has a documentary crew following him around as he sets about completing this goal.