Sign the Stars Anywhere on Earth With the First International Astronomy Dictionary For Deaf Communities

The encyclopedic list includes more than 40 space terms ranging from the Moon to exoplanet

International Astronomical Union
International Astronomical Union

It’s been a long time coming, but the international deaf community is finally getting a comparative dictionary to help translate astronomical terms, Mike Wall reports for

Organized by the International Astronomical Union (IAU), the encyclopedic dictionary adds on to previous efforts—including existing 300-term dictionaries in English, French, and Spanish, and projects like Scotland's impressive 2013 effort to develop signs to describe the solar system.

While the new international dictionary includes just 47 terms, the resource has compiled the signs in multiple languages, including German, Italian, Portuguese, Japanese and Polish.

The dictionary spans the gamut from basic to complex technical jargon. While common-use terms like the Moon are given a sign in nearly every language, newer terms like exoplanet have spottier coverage (exoplanet has only been given a unique sign in Spanish so far). The dictionary also includes more technical terms like nadir (the location directly below an observer) and zenith (the location directly above).

“Many astronomical words have no equivalent hand sign in any sign language,” writes the IAU in a press release. The organization is hopeful, however, that the dictionary will help communities develop missing signs. In the future, it intends to continue work on the dictionary by offering suggestions for countries that do not have a sign for some words.

One possibility to fill in missing terms is to use signs from closely related languages (like signs from Spanish for the Italian community). A more ambitious possibility is to analyze signs to identify recurring patterns and combine that with the unique characteristics of a country’s particular sign language to develop new signs. “This may be an impossible task, but it is one worth exploring,” the IAU notes.

Developing new terminology in sign language is both an art and a science, but IAU found that in most countries, signs encompass key traits of the concepts. A pattern among signs for gas giants for instance reflect notable characteristics like Jupiter’s big red spot and Saturn’s rings. Other times, the signs have more indirect associations—as journalist S.I. Rosenbaum points out on Twitter, in American Sign Language, the sign for stars is the sign for socks flipped upside-down, conceptually referencing the link between ground and sky.

For ASL speakers specifically, the inclusion of new words is an organic process, and more space terms are likely to be formally established through a combination of borrowing words, deliberately developing new ones, and creating emergent signs as they’re needed.

The IAU dictionary is the latest in decades of work to ensure deaf communities are welcome in space exploration. The first person to use sign language in space was NASA astronaut Bill Readdy during a space shuttle mission in 1992, reports Zoe Macintosh for, followed by Tracy Caldwell Dyson who signed a message of inclusion from the International Space Station in 2010.

"One thing I have learned is that deaf people can do anything,"  Caldwell Dyson signed from her perch more than 200 miles above Earth’s surface.