He'd spent seven years looking for the perfect shot. Then with the click of his camera one magical evening, he finally nailed it. Greg McCown is a photographer, storm chaser and native of Tucson, Arizona. On Aug. 8, 2015, near the town of Marana, Arizona, McCown took a picture that's since become world-famous. Titled "Lucky Strike," his photo shows a jagged bolt of lightning dance across a desert rainbow. What a dramatic combination. (See his image in the tweet below.)
It's unusual to see those two meteorological phenomena occur in the same place at the same time. And photographing them side-by-side is often extremely difficult. Lightning and rainbows can happen simultaneously, but the weather conditions must be perfect — and to capture it on camera, you have to be there, facing the right direction at the exact right time.
As a wise Muppet once said, rainbows are only illusions. They're the product of perception and do not physically exist. Speaking of things that aren't what they appear to be, let's talk sunlight. People tend to think the nearest star is yellow or orange, but if you viewed it from outer space — above Earth's atmospheric distortions — you'd see that the light produced by our sun actually looks white.
White light is a blend of all the different colors in the visible light spectrum. Each one travels at its own wavelength, with some being shorter than others.
Regardless of color, a beam of light's trajectory can change once it encounters a new medium. Air is less dense than water, and light that's passed through the former bends — or "refracts" — when it enters the latter.
Rainbows only become visible to us while large quantities of water droplets fill the air. And that's just one item on the checklist. To see a rainbow, you need to stand with your back to the sun. But if that big ball of plasma is obscured by clouds or precipitation, you won't get to witness any colorful arches. In order for a rainbow to appear, the sky around the sun has to be nice and clear.
Once all the criteria have been met, it's showtime. First, the sunlight emanating from behind you enters the water droplets. On their journey through a bead of H2O, the light's component wavelengths all bend at different angles and get separated. Next they'll hit the back of our droplet. Bouncing off of this, the wavelengths travel back toward you, refracting a second time over while they exit the water.
Here's where your eyeballs come in. Each droplet in the watery haze before you will only send out one color that's at the right angle to meet your eyes. Thus, the colors of the rainbow become segregated, with red at the top and violet at the bottom.
This is by no means the whole story; we haven't even mentioned the fact that rainbows are circular. But for now, let's move on to a more striking topic.
A Story of Opposites
Unlike rainbows, lightning is something you can touch. Not that you'd want to: Paralysis, cardiac arrest and untimely death are among the many terrible things that've happened to those who have come into contact with it.
Most of us are familiar with the type of lightning that bridges the gap between the bottom of a storm cloud and the ground. But a lightning flash can also form within a single cloud — or horizontally connect two of them. Lightning may even occur inside the plume of a volcanic eruption. (How awesome is that?)
In all cases, lightning is forged by opposite charges. Ice crystals, water droplets and floating dust specks are the three primary ingredients of storm clouds. Through a mechanism scientists don't fully understand yet, these little bodies acquire positive and negative charges. Positively charged particles move up to the top of the cloud while those with negative charges congregate around the bottom.
All that negativity on the cloud's underside has the effect of giving the ground below it a positive charge. The tops of trees, buildings and people who happen to be standing under one of these clouds become positively charged as well.
Lightning strikes are a response to these imbalances; the insanely hot flashes of electricity briefly equalize the charged parts of the atmosphere that had grown polarized.
When It All Comes Together
Your ability to perceive lightning doesn't depend on how well-lit it is outside or where your feet happen to be planted. But again, rainbows are only visible from a particular vantage point and when the lighting is favorable.
That's why rainbows and lightning are infrequent companions. Storm chaser McCown tweeted he'd been trying to document the two together for seven years before the right opportunity arrived. When he shot "Lucky Strike," he was standing with his back to the sun. The sky around the setting star was clear, but polarized storm clouds were still looming ahead of the cameraman.
It's uncommon to find yourself in that very specific situation. Still, once in a while, somebody beats the odds and has a camera in hand when lightning dances around rainbows.
A sheriff in the Texas panhandle hit the jackpot in 2015 when he photographed a cloud-to-cloud lightning flash splitting a double rainbow. Astronomer Phil Plait accidentally caught the same display on film while shooting a YouTube video on his Colorado lawn.
Depending on where you live, your chances of taking a lightning/rainbow picture might vary from season to season. Tucson enters a yearly monsoon period from mid-June to late September. The scattered storms across this wide, open terrain — where you can watch a developing tempest from 50 miles (80.4 kilometers) away — are a godsend to nature photographers in the area. Some of them, including McCown, have successfully caught lightning-flanked rainbows during those months.
By all accounts, the experience is unforgettable. Who wouldn't want to see a half-halo of color meet the zigzagged symbol of destruction? Nature is truly a wondrous thing.