How Do Fireflies Glow? Mystery Solved After 60 Years

Scientists have sussed out the chemical secret of these bright summertime beetles—and it may someday improve human health, a new study says.

Think of the firefly abdomen like a black box of bioluminescence.

For around 60 years, scientists have known what basic ingredients go into the box—things like oxygen, calcium, magnesium, and a naturally occurring chemical called luciferin.

And they've known what comes out of the box—photons, or light, in the form of the yellow, green, orange, and even blue flickers you see dancing across your backyard on summer nights.

But until recently, the actual chemical reactions that produce the firefly's light have been shrouded in mystery. And scientists like Bruce Branchini at Connecticut College love a good mystery. (Also see "Fireflies Are 'Cannibals'—And More Surprising Facts About the Summertime Insect.")

"The way enzymes and proteins can convert chemical energy into light

DON'T MISS THE REST OF THIS STORY!
Create a free account to continue and get unlimited access to hundreds of Nat Geo articles, plus newsletters.

Create your free account to continue reading

No credit card required. Unlimited access to free content.
Or get a Premium Subscription to access the best of Nat Geo - just $19
SUBSCRIBE

Read This Next

AI can help you plan your next trip—if you know how to ask.
Did this mysterious human relative bury its dead?
This new birth control for cats doesn't require surgery

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet