In recent months, Elliot McGucken, a photographer and physicist, has embarked on nocturnal expeditions into the wilderness of southern California armed with a camera and a drone. His journeys have taken him to breathtaking locations such as the Trona Pinnacles and the Mobius Arch formation, where he goes beyond capturing landscapes and celestial bodies. McGucken employs his drone to add a captivating element to his photographs: giant spiraling cones of light. These luminous hourglass shapes, achieved through long-exposure shots lasting several minutes, are artistic representations of a fascinating physics concept known as a light cone.

“I’ve always been fascinated by the light cone, as it often goes unnoticed,” shares McGucken in an interview with Smithsonian magazine. Through his project, he hopes to inspire a sense of wonder in people and ignite their curiosity. “People should take the time to contemplate and marvel at this phenomenon,” he adds.

In essence, light cones visualize the path of light through space and time. Specifically, they illustrate the propagation of light that radiates in all directions from a single point. The concept was initially conceived by the German mathematician Hermann Minkowski in the early 20th century and later employed by Albert Einstein in his groundbreaking work on relativity.

To understand light cones, envision switching on a light bulb that emits light in every direction infinitely. Initially, the light appears as a tiny dot, but as time elapses, it expands, illuminating larger areas as it moves outward. Within fractions of a second after the bulb is switched on, the light encompasses a small sphere around it. With each passing fraction of a second, the light travels farther, creating progressively larger spheres.

Light cones trace the expansion of light in two-dimensional space, radiating outward in increasingly wider circles from a central point. Analogously, dropping a stone into a pond generates ripples that spread across the water’s surface. In two dimensions, light from a bulb fills expanding circles as time progresses.

If these two-dimensional circles were stacked atop each other, with the smallest at the bottom and the largest at the top, they would form a shape resembling an ice cream cone. This cone represents both space and time. As one moves farther from the cone’s apex, more time has passed since the light bulb was turned on.

However, the light cone concept encompasses more than just the cone’s top half. The mirrored bottom half represents locations in the past from which light can travel and reach the observer and the light source in the present. The narrow section of the inverted cone symbolizes moments in the recent past, situated close to the observer. Light from these moments takes less time to reach the observer because it originates from nearby. Conversely, the wider sections of the inverted cone signify more distant past events. For light to have reached the observer from those moments, it would have had to originate from much farther away.

Minkowski’s work on light cones and their relationship with space and time provided crucial insights for Albert Einstein in formulating the theory of general relativity. This theory explores how gravity influences both space and time.

While relativity may seem abstract, it has tangible implications in everyday life. For example, without adjusting satellite clocks for relativity, GPS systems would lack the required accuracy to be functional. Satellites, positioned far from Earth, experience a weaker gravitational pull, causing time to pass slightly faster for them compared to clocks on the ground. Additionally, their high-speed orbits slightly slow down time. Even operating McGucken’s drone relies on an understanding of relativity, as its position is determined by GPS. Thus, the art project sets up a meta premise—the traced light cone of the drone honors the theory of relativity, which is essential for its existence.

“It’s a fun aspect that I didn’t initially consider,” remarks McGucken. His light cone artwork initially involved 3D-printed cones, but he later conceived the idea of representing them using a drone—a form of “painting with light,” as he describes it. The drone’s flight path is pre-programmed to trace the shape of two mirrored cones, starting from the wider bottom of the lower cone and spiraling upward to create the top spiral.

On average, McGucken’s cones span approximately 40 feet in width, and when combined, the two halves reach a height of around 70 feet, akin to a seven-story building. While they differ slightly from the true theoretical light cones, which do not spiral, McGucken’s artistic interpretation adds a unique visual dimension. Using long-exposure techniques, the camera captures the illuminated path left by the drone. Each shot takes roughly ten minutes to complete, and McGucken often takes multiple shots in a row to ensure optimal results. He revisits locations on different nights to refine his setup and enhance the quality of his images.

Occasionally, wind gusts may slightly alter the drone’s intended path. “The most perfect spirals occur on windless nights, which are hard to come by in the desert,” McGucken explains. In addition to the ethereal cones, the photographs also showcase the natural beauty of the surrounding landscapes. McGucken strives to align the diagonal edges of the cones with the natural lines of the rock formations beneath them. Furthermore, many of his images capture streaks of stars in the night sky—a mesmerizing effect achieved through the long-exposure technique.

While McGucken’s photographs do not aim to convey a specific physics lesson, he hopes they will ignite a desire to delve deeper into the subject matter. By capturing the allure of light cones in his artwork, he invites viewers to explore the captivating realms of physics and unravel the mysteries of our universe.

By Impact Lab