From 'The Suspense of Strangeness', Nature 2001, Maurice Riordan:

There is a line about moonlight by Sylvia Plath that I find haunting: “This is the light of the mind, cold and planetary.” My ear is arrested by the rhythm — by the way the line runs quickly into the strong stress on “mind”, which then collides immediately with the stress on “cold” before the line spins off into space. Except the space created by the metaphor is inner space, so that there is also a collision of inner and outer worlds. The effect is disturbing, is meant to be disturbing: the imagining mind is breached, cleaned out and (for a moment) exhilarated by the hostile image of nature. 

The line is scientific, of course, only in the flimsiest sense. Even so, to the degree that it is, it is crucial to the effect: “light” generally brings associations of illumination, vision, transcendence. But not here: the use of “planetary” erases these associations and replaces them with physical, actual light. 

This illustrates something about how poets use words with scientific associations. They exist in a state of sensitive relationship with everything else in a poem — and on an equal basis, which means they have to work: they must earn their keep by at least increasing the surface tension of the language. They are, then, part of the poem's imaginative exertion, that promiscuous agility of language which, as described by the nineteenth-century Italian poet Giacomo Leopardi, “keeps the mind in constant and lively movement and action, transporting it suddenly, and often abruptly, from one thought, image, idea, or object to another, and often to one very remote and different; so that the mind must work to overtake them all, and, as it is flung here and there, feels invigorated”. 

One very remote and different: Leopardi's phrase suggests the particular lure science has for poets. Science supplies a register of words outside common usage; it provides a stock of ideas often far removed from our everyday observation of things; and this body of knowledge seems to be an objective description of the world. Thus, science has the potential to give a poem what the American poet Elizabeth Bishop called “the suspense of strangeness”, a sense of being in a world that is at once engrossing and unpredictable.