What Does an Eclipse Sound Like?

How would you describe an eclipse to a blind person? The moon moves in front of the sun, yes. But what does that look like? Someone trained in illustrative description of images might say, “The moon appears as a featureless black disk that nearly blocks out the sun. The sun's light is still visible as a thin band around the moon's black disk. To the upper right, at the moon's leading edge, a small area of sunlight still shines brilliantly.”

That’s just an example of how such an event could be described. Bryan Gould, director of accessible learning and assessment technologies at the National Center for Accessible Media, a non-profit working to make media experiences accessible to people with disabilities, is hoping to offer oral descriptions of the eclipse in an app. Paired with other features, like a tactile diagram and audio from the changing natural environment as the eclipse darkens the sky, the app is designed to make the event more accessible to blind or visually impaired people who want to experience it.

Gould is working with Henry Winter, a solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics, to develop the app, called Eclipse Soundscapes. As the August 21 solar eclipse darkens a path across the United States, Eclipse Soundscapes will release descriptions, timed—based on the user’s location—to match the progress of the eclipse.

Winter conceived Eclipse Soundscapes after a conversation with a friend who’s been blind since birth. She asked him to explain what an eclipse means.

 “I realized I didn’t have the vocabulary to answer that question for her,” says Winter. “Every way I thought about it was visual in nature, and I didn’t know how to explain it to somebody … light, dark, bright, dim, flash. All these different words have no meaning to somebody that’s never seen.”

But the project goes well beyond audio descriptions. It includes two further elements: audio of the changing soundscape caused by the eclipse, and a tactile exploration of the eclipse’s image (which means that people who are blind or visually impaired can “feel” the eclipse using vibrations on their smartphones).

Many creatures become active as the sun sets, and many of them use darkness as an indicator of time of day. During an eclipse, crickets will chirp and frogs will chorus, thinking night has fallen. These habits were noted as far back as 1932, in a Proceedings of the American Academy of Arts and Sciences article titled “Observations on the Behavior of Animals During the Total Solar Eclipse of August 31, 1932.”

Such an event might provide an interesting representation of the eclipse, thought Winter, so he partnered with the National Park Service’s Natural Sounds program, which preserves and catalogs sounds from the parks. Helpers stationed at national parks along the route will record audio during the eclipse, to hear the change in the “bioacoustical chorus” of the animals.

This can’t happen in real time, of course, so the National Center for Accessible Media is providing illustrative descriptions, based on a previous eclipse. The sounds of crickets, frogs and birds becoming active on the day of the eclipse will be added to the app later.

Last, with the help of an audio engineer named Miles Gordon, Winter is trying something completely new. Gordon developed a “rumble map” of the eclipse: The app places images of different stages of an eclipse on your smartphone’s screen, and as you trace your finger across the eclipse’s image, the vibration increases or decreases based on the brightness of the image.

“It does give you the impression that you’re actually feeling the sun, as you move your finger around,” says Winter.

Scientists around the world will be using the eclipse as an opportunity to study solar astronomy in a way they usually can’t, measuring the ultraviolet light emitted from the sun’s corona, which Earth-based observers can’t normally see, as it is overpowered by the normal sunlight. It’s also rare for an eclipse to cover this much land — it traverses from Oregon to South Carolina — and Winter points out that it is a particularly good opportunity for education and outreach.

Though education is important, for Wanda Diaz Merced, a visiting scientist at the Harvard-Smithsonian Center for Astrophysics who is completely blind, there’s a lot more to the eclipse than that. Merced, who has consulted on the Eclipse Soundscapes project, studies human-computer interaction and astrophysics, and to do her research, she needs assistance translating data into a format she can interact with. She’s been building tools to help with that translation, and sees elements of Winter’s project that could contribute.

“It’s still not a prototype that I may use, for example, to study elements of the photosphere. It is not on that stage,” says Merced. “But hopefully one day we will be able to not only hear, but to touch.”

The eclipse will occur on August 21, starting around 10 a.m. in Oregon and finishing by 3 p.m .in South Carolina. The Eclipse Soundscapes app is available for iOS now, and the team is working on an Android app as well.

Nathan Hurst | READ MORE

Nathan Hurst blends a love of storytelling with a passion for science and the outdoors, covering technology, the environment, and much more. His work has appeared in a variety of publications, including Wired, Outside, Make: and Smithsonian.