In my A Quiet Rebellion books (not yet published, but I’m inching towards it), a recurring element is animals’ eyes glowing in the dark. This isn’t anything terribly mysterious: it’s just observations characters make about the tapetum (an anatomical structure at the back of the eye), from the perspective of a society that views all mammals as potentially dangerous. The tapetum is addressed in a previous interview with Charlotte, a veterinary ophthalmologist.
Animal eyes aren’t the only things that glow in my books. Leading away from the capital city, there’s a tunnel several miles long where the lighting is provided by glowing mushrooms. Because my society has regressed from a more advanced one, I was reasonably comfortable with the idea that the original Settlers seeded (I guess that should be “spored”?) the tunnel with bioengineered mushrooms to provide a self-sustaining lighting system. I’m not going to get too hung up about just how these mushrooms have survived over the years, although I’m sure insects that fly into the tunnel help with spore dispersal as well as providing some nutrients (along with whatever rubbish the human travellers drop).
What is bioluminescence?
In my very simplistic view (hey, I’m a medical doctor, not a real scientist), bioluminescence is the production of light through an oxygen-dependent chemical (enzymatic) reaction. It occurs in quite a variety of living organisms including fungi, bacteria, insects (fireflies, glow worms), fish and marine invertebrates. It differs from fluorescence in which the energy for light emission is derived from incoming (“exciting”) radiation. Funnily enough, I know more about the principles of fluorescence rather than bioluminescence since it’s used in both ophthalmology and the laboratory, so I encounter it in my day job.
There’s a good (not too complex) explanation of the phenomenon in this Natural History Museum article.
Here’s a recent open access original research article from Kaskova et al which goes into depth regarding the science of fungal bioluminescence.
To be honest, much of the above article was rather over my head, so I was happy to find this article on Phys.org which provides a more lay-orientated view of the Kaskova article.
Interestingly, I’ve encountered a number of other writers on Scribophile who feature bioluminescent, chemoluminescent or other glowing items in their works (and not necessarily magical). Fellow Scribber Matthew Dewar has uses bioluminescence in one of his works in progress: his published works are available here.
Why is bioluminescence (and its equivalents) a popular way to add ambience to a world? I think it’s because there’s something almost magical about living organisms or even inert objects that glow without an obvious power source. Even though light is “just” another form of energy, like kinetic (movement) energy or sound, we humans can’t produce it ourselves.
And there are some beautiful images of glowing fungi in this Mother Nature Network article.
Of course, it’s not only fungi that glow. Check out these glow worms on National Geographic’s site.
And only slightly related, but I thought this was a fascinating article on Atlas Obscura about fluorescence and ultraviolet reflectance in birds.
Are there stories you have read where the lighting systems made an impression on you? Let us know in the comments!