An example of extended metaphor and mixed metaphor in popular science writing:
"If the 'new' comets seem to be coming from starting points half a light-year out, that is where they have been in residence since the birth of the Solar System. Such is the leading idea about the origin of comets, that is to say the theory not disfavoured in Cometsville. All the other other categories of comets are, in this scheme, pilgrims from the coolest provinces of the Solar System who lost their return tickets and are trapped in shorter orbits around the Sun, waiting either to perish in the heat or to be evicted into interstellar space and exiled from the Sun for ever. But the theory requires the existence of a large population of unseen comets to sustain the pilgrimage, and thus it endorses the opinion of Johann Kepler that 'there are as many comets in the sky as fishes in the sea'.
The devotion of comets to the gravitational faith that unites the Solar System appears in this: their first journeys from the outer darkness to the altar of the Sun take a very long time indeed, for the sake of a fleeting visit. When the priests of this faith, the celestial mechanicians on the Earth, interrogate 'new' comets now arriving in the Space Age they admit to travelling for several million years."
Nigel Calder
Calder, N. (1980). The Comet is Coming! The feverish legacy of Mr Halley. British Broadcasting Corporation.
This passage has extensive use of metaphor.
There is an extended metaphor: pilgrims, pilgrimage, preists, devotion, faith, altar – which could be considered as an implicit analogy (that is, each term could be mapped onto a more technical term), but there are also other metaphors: residence, birth, 'Cometsville', return tickets (could be considered part of the extended metaphpor), eviction, exile (=excommunication?), interrogation.
Read examples of scientific analogies
