I just re-read a popular astronomy book that was published when I was a child, about 1973. It starts with an interview to Harold C. Urey where the interviewer asks about a hypothetical planet in our solar system called Biga.
Has a hypothetical planet ever been called "Biga" by its proponents, in the same way there was a proposed planet "Vulcan", or is this "Biga" name a printing or translation error?
If it's a mistake and there never was a "Biga" proposal, which is the proposed planet with the most similar name?
This link contains such interview, in Spanish. I will translate and quote its most relevant text:
Interviewer: At present, do we know all the planets of the Solar System, or is there the possibility of still unknown planets in our system?
H.C. Urey: We certainly know the nine usual planets. Recently there has been much talk of another object moving in space and supposed to be close to the Solar System, but I am not sure that it is a real hypothesis, and personally I think it is better to wait before deciding whether it is Not of a planet. I consider it sufficient to say that there are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto and the asteroidal belt.
Interviewer: When talking about this object, are you referring to the so-called planet Biga?
H.C. Urey: Yes, that's what I meant, but I'm not sure of its existence.
1- This interview mas made about 45 yeras ago.
2- I'm not asking if this hypothesis is correct or even possible. Only want to know more about this hypothesis which was well known by H. C. Urey in the 70's.
3- I'm not asking if the name "Biga" is a correct proposal of a name for a planet in our Solar System accordind to current naming rules.