PLANET OF ORIGIN: Earth
Recruited by Brigadier Lethbridge-Stewart to serve as UNIT’s scientific advisor, it's pure bad luck for Liz that this coincides with the Doctor being exiled to Earth and needing a job. Liz is a brilliant scientist with multiple degrees (physics and medicine amongst them) and can also speak French. As opposed to earlier companions, Liz doesn't need the Doctor to explain everything to her, which may have been why she has such an ignominious exit, leaving between seasons without a goodbye scene. Liz is an equal to the Doctor, but at the time what producers wanted was a sexy girl who could ask the Doctor to exposition at them.
PLANET OF ORIGIN:
DOCTOR(S): Fourth, Fifth
Most companions end up going through traumatising experiences while travelling with the Doctor, but Nyssa starts off her travels by losing her entire species. Growing up as the beloved only child of the kindly Tremas, it's a bit of a shock when her father’s body gets taken over by the Master, who then goes on to accidentally destroy part of the universe through entropy (including Nyssa’s planet – luckily, she's watching from a safe distance). Nyssa's a caring, trusting person, who never actively seeks revenge on the Master. She's a scientist, a bioelectronics expert who ends up leaving the TARDIS in order to turn a plague ship into a proper hospital. But unlike some other companions (Adric), her intelligence doesn't mean that she considers herself better than anyone else. Instead, Nyssa's one of the kindest and friendliest companions to have ever travelled with the Doctor.
It's the battle of the scientists!
But who do you prefer - no-nonsense Liz, or nice Nyssa?
Let us know in the comments below!