Unlike on Earth where the length of seasons are almost of the same duration each time, the hypothetical planet on which Game of Thrones took place has seasons of arbitrary length i.e. some winters last for three years, some lasts for six years and some for decades.
Question 1: Is it scientifically possible for a planet revolving around a single star to have seasons of arbitrary duration
Question 2: Is such a scenario possible in a planet in a binary or a higher star system?