WMG: Bill Nye the Science Guy

Bill Nye is a Time Lord
A strange man with a love for showing people strange things (Doctor Who was originally conceived as a Edutainment Show) and for bow ties with a title starting with "The". The children that regularly appear on the show are his companions. His TARDIS is Nye Labs.

Bill nye is the reincarnation of abe lincoln
Or was sent back to the 1860s to end the civil war and free the slaves

Bill nye is a terminator
The theme song has him talking with a woman's voice, terminators can do that plus the abe lincoln thing suggests he went back in time