The Atlanta rapper told people to "do your research on David Irving". Getty

Atlanta rapper B.o.B. has continued his Twitter war against physics with a new song that criticises Neil deGrasse Tyson and tells people to look up noted holocaust denier David Irving. The rapper, real nameis Bobby Ray Simmons Jr., also says "Stalin was way worse than Hitler, that's why the POTUS gotta wear a kippah", referencing times when US President Barack Obama has worn the traditional Jewish cap.

In the song, entitled Flatline, B.o.B. also criticises famous physicist DeGrasse Tyson, who made headlines for his Twitter retaliation to the rapper's claims that the Earth is flat. A clip of Tyson speaking about the Earth not being a sphere but instead being an oblate spheroid shape is also featured in the song.

In Flatline, B.o.B. says Tyson should "loosen up his vest" and accuses the physicist of being paid-off by saying "they'll probably write that man one hell of a check". Later in the song, he tells people to "do your research on David Irving". David Irving is a noted racist and anti-Semite who spent over a year in prison in Austria for his denial of the holocaust.

The rapper also tells people to "look up Dr Richard Sauder". Sauder has written books espousing the theory that there are a network of underground and underwater tunnels that hide UFOs.