Photography and science have gone hand in hand since Louis Daguerre used his fossil collection as the subject of one of his first daguerreotypes. But photography has also contributed to scientific knowledge, expanding our understanding of the world by capturing what the human eye cannot see or going places humans could not yet go.

Here are seven instances in which film photography, simply by virtue of being able to capture static images, added to our understanding of the world. Today, in a world where we see constant videos from the depths of the ocean and photos from space appear in our Twitter feeds, much of this seems obvious. But these photos represent both incredible technological achievements and contributions to human scientific knowledge.


1. How Horses' Legs Move When They Gallop

In paintings, it's not uncommon to see a galloping horse with its legs outstretched, all four hooves off the ground. It's a popular image, and one that's entirely wrong. In the late 19th century, the question of whether a horse ever took all four feet off the ground mid-gallop was so hotly debated that industrialist and former California governor (and future university founder) Leland Stanford commissioned photographer Eadward Muybridge—who had already photographed Stanford's horse Occident at racing gait—to settle it once and for all.

To photograph Sallie Gardner, Muybridge set up 24 cameras, with each shutter controlled by a trip wire triggered by the horse's hooves. The jockey rode her across the setup at 36 miles per hour, and thus Muybridge captured his most famous motion series, 1878's Sallie Gardner at a Gallop. He also invented the zoopraxiscope, which let him show the series as a stop-motion film. With that, he finally solved the mystery of the horse's gallop: all four hooves do come off the ground, but while they are all pulled in, not while outstretched. Muybridge went on to create hundreds more motion studies of animals, including humans. Today, scientists, painters, and animators still refer to Muybridge's Animal Locomotion series.


Photo series by Eadweard Muybridge via Wikimedia Commons.

Earlier humans, however, were much better students of animal gait. In comparing artistic representations of animal movement against the actual movements of those animals, a group of Hungarian researchers found that, out of all the pre-Muybridge era artwork they studied, prehistoric cave paintings were the most accurate. So perhaps we might not have needed Muybridges' cameras after all, if only we shared our predecessors' powers of observation.


2. How Cats Land on Their Feet

Étienne-Jules Marey was a physiologist first and a photographer second, but like Muybridge, he used chronological series of photographs taken in rapid succession to study movement. He invented a chronophotographic gun (which resembled a shotgun with a film reel attached), which could capture 12 consecutive frames a second on a single image. He compared his chronophotographs to the anatomy of his subjects so that he could understand not just the exterior movements of each subject, but the movements of their skeletons as well. In fact,

Marey was such a keen observer of animals that he posited the truth about the galloping horse's movement years before Muybridge's motion series.


One of Marey's most famous series has enjoyed a bit of a revival in the age of YouTube because it is commonly called "The First Cat Video." Marey wanted to get a glimpse of how falling cats change their position to land on their feet. In the 1880s, he took numerous sequential photos of cats being dropped and landing on their feet, capturing the way in which a cat twists its body to get into the proper landing position. Marey's photos suggested that cats possessed a physiological mechanism for landing on their feet, but many scientists were skeptical, even with the photo evidence. Henry R. Miller and Lewis H. Weed would eventually prove the falling mechanism beyond a shadow of a doubt in 1916 by dropping blindfolded cats whose balancing vestibular organs had been destroyed in both ears. Those cats dropped straight to the ground with no twisting or turning, confirming what Marey had done 30 years earlier with far less damage to the cats involved.

Cats, for the record, were not the only animals Marey dropped. Like Muybridge, he photographed numerous motion series, and he repeated his cat experiments with bunny rabbits:

3. How Birds, Bats, and Insects Fly

Another particular passion of Marey's was the study of flight and how insects and birds managed to keep themselves aloft. His first explorations were not photographic; he developed an apparatus called an "air pantographe," which he harnessed to birds and dragonflies to trace the path of their flights. In that way, he was able to measure the elliptical trajectory of their wings, contributing greatly to our understanding of flight. But as Marey became increasingly interested in the possibility of human flight, he sought more information on the mechanics of flying animals. (Also, he was a staunch opponent of vivisection, which he felt did not yielded useful information on the workings of a living, squirming animal.)


Marey was excited to see Eadweard Muybridge's "Sally Gardner at a Gallop" in the pages of La Nature, and with visions of ornithopters flapping through his head, contacted the magazine to put him in touch with Muybridge. Marey had, for some time, felt that a visual solution would be the ideal way to solve the mysteries of animal aerodynamics. Muybridge told Marey that photographing birds in flight would be difficult, but that he would try. In the meantime, he attempted to build aircraft, including fixed-wing aircraft, with fell aviation enthusiast Victor Tatin.

Photo by Étienne-Jules Marey, via Wikimedia Commons.

Marey eventually returned to his study of birds in flight. He was disappointed in the flight locomotion photos provided by Muybridge, which would lead him to attempt his own experiments in chronophotography. It took a number of experiments and adjustments of his chronophotographic gun, but Marey was finally able to record the visual data that allowed him to more fully study flight. The Wright Brothers credited Marey's 1890 book, The Flight of Birds, which contained photographs, drawings, and diagrams as well as his written research on bird flight, with aiding their own successful flight. Unfortunately, Marey didn't live to see planes fill the skies; he passed away in May 1904, just months after the Wright Brothers' first successful flight.


4. How a Bubble Bursts

Lucien Bull worked as one of Marey's assistants and headed up the Marey Institute after Marey's death. Marey's initial interest in photography may have come from physiology, but his photos also study aspects of physics like wave motion and air dynamics, and Bull continued in that scientific tradition.


Bull invented a high-speed camera that allowed him to capture one of his most famous series, 1904's Soap Bubble Bursting. The images show a pellet shooting through a soap bubble, and, for the first time, offered a clear sequence of the bubble retracting and eventually dispersing. By rendering these almost invisible actions visible, Bull was able to make great contributions to the field of fluid mechanics, giving researchers data they never had access to before.

5. Animals Live on the Ocean Floor, Miles Below the Surface

Like his predecessors in the field of high-tech photography, Harold Edgerton was very interested in motion and capturing moments that are two quick for the human eye to register. He's best known for photo series like "How to Make Applesauce at MIT" (depicting a bullet that has just been shot through an apple), his "Milk Drop" photos (he was especially fond of photographing drops and splashes), and his photos of the first few moments of nuclear explosions. But he was also interested in the ability of the camera to go places humans did not yet go.


Photo from Gail Buckland's First Photographs.

Edgerton collaborated with inventor and famed nautical explorer Jacques Cousteau to build a camera that could withstand pressures of 5 1/2 tons per square inch. They also developed a system of sonic pings that would tell them how far down the camera was from the ocean floor as they lowered it. When, in 1956, they got just above the floor, roughly 24,600 feet down, they snapped a photo, which showed them that even so far down, unseen by human eyes, the ocean teemed with life. At the same time, Edgerton was using sonar technology to create a different kind of image of the ocean floor. In 1960, Jacques Piccard and Don Walsh would personally witness a lower depth, 35,810 feet, while riding in a bathyscaphe, and they would also report seeing plenty of life. Edgerton sent them a camera for the trip, but it didn't make it aboard.


6. What the Beginning of a Nuclear Explosion Looks Like

As mentioned above, Edgerton was well known for his photographs of the early moments of nuclear blasts. After World War II, the Atomic Energy Commission contracted Edgerton, Kenneth Germeshausen, and Herbert Grier to photograph nuclear bomb tests. Because the explosions involved such a huge release of life, the trio needed to devise a camera that captured exposures of far, far shorter duration than anyone had before. Together, they developed the "rapatronic" camera, with a shutter with no moving parts that could shoot photographs with an exposure time of from four- to ten-millionths of a second. The photos had to be shot miles from the detonation site. The photographs provided government researchers with information on nuclear explosions that they would not have been able to obtain without the rapatronic camera.


Photo by EG&E, via Wikimedia Commons.

7. What the Earth Looks Like from Space

The first images of the earth taken from space were not beamed back from space, but shot on film and carried back to Earth. In 1935, the Explorer II balloon wouldn't quite make it up to space, but it would travel 13.7 miles above sea level, high enough to photograph the curvature of the Earth. But it wasn't until October 24, 1946, when a V-2 rocket was launched from White Sands Missile Range in New Mexico and reached suborbital space, hitting an altitude of 65 miles, that we got our first look at the Earth from space. Although the scientists at White Sands were excited to see those first images, S. Fred Singer, who was working at the time at the Johns Hopkins University Applied Physics Laboratory, told the Air and Space Magazine that they weren't initially interested in the meteorological significance of the clouds and, in fact, considered them a "nuisance." We wouldn't see the iconic Earth images like "Earthrise" and "The Blue Marble" until we'd send human photographers to take them.


Photo by the US Army, via Wikimedia Commons.


The Edgerton Digital Collections project, accessed March 13, 2013.

Marta Braun, Picturing Time: The Work of Etienne-Jules Marey (1830-1904).


Gail Buckland, First Photographs: People, Places, & Phenomena as Captured for the First Time by a Camera.

Naomi Rosenblum, A World History of Photography, Fourth Edition. Aaron Scharf, Pioneers of Photography.

Ann Thomas, Marta Braun, National Gallery of Canada, Beauty of Another Order: Photography in Science.