Example of simile in popular science writing:
"Now I must introduce you to the idea that this immense disc of gas and stars [the Galaxy] is in motion, that is it turning round in space like a great wheel. … The main motion of a star is along a path that is roughly a circle with its centre at the centre of the Galaxy. The Sun and the planets move together as a group around such an orbit. The speed of this motion is in the neighbourhood of 500,000 miles an hour. But in spite of this seemingly tremendous speed it nevertheless takes the Sun and its retinue of planets about 200,000,000 years to make a round trip of the Galaxy.
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Previously we saw that the Milky Way is all that we can see of a huge disc-shaped cloud of gas and stars that is turning in space like a great wheel. We referred to this cloud as our galaxy."
Fred Hoyle (1960) The Nature of the Universe (Revised ed.), 1960
Read about examples of science similes
The sun's "retinue" of planets is a use of metaphor – the planets move with the star like the retinue of officials, assistants (and sometimes hangers-on) accompanying a leader or celebrity.
