An example of metaphor in popular science writing:
"Castor is one of the two bright stars of Gemini, a constellation of the Zodiac. Together with its partner, Pollux, it can be seen on any clear winter night."
Fred Hoyle (1960) The Nature of the Universe (Revised ed.), 1960
[Presumably the observational comment relates to Northern hemisphere observers.]
Castor and Pollux are named after two mythical half-brothers, and the 'partners' reference is perhaps more relevant to the mythical characters (said to be twins 'gemini' although having different fathers).
Although the stars are in the same constellation, the constellations are not actually closely located groups of stars, but merely groups that have been psychologically associated from the perspective of earth observers. So, although appearing close from our viewpoint Castor and Pollux are actually very far apart. Nor can they be considered as 'partners' by virtue of being similar kinds of stars:
"Castor lies at a distance of 51 lightyears while Pollux is closer at 33.8 lightyears….
Pollux is brighter and shows a more orange-hued colour than its mythological twin…Visually, Castor is dimmer and more yellow than orange Pollux….
Pollux is an old giant star…[whereas Castor] is in fact a complex multiple star."
BBC Sky At Night Magazine
