We are SO happy to announce that Zooniverse has reached an extraordinary milestone: 1 BILLION classifications contributed by volunteers!

To give you a sense of what an extraordinary milestone this is: if each classification only took 1 second to complete, 1 billion classifications would require 31.7 years of full-time effort. Based on a query of our Zooniverse statistics server, we estimate that these billion classifications are collectively equivalent to around 2,000 years of full-time effort. The scale of this milestone is utterly implausible for an individual, and highlights the extraordinary power and promise of digital participatory research.

Since the launch of Galaxy Zoo in 2007, 3+ million volunteers across 160 countries have taken part in more than 550 projects. These projects are hosted by teams based at a wide range of institutions, including research universities as well as laboratories, libraries, archives, museums, state and federal agencies, galleries, technical institutes, and community colleges. 

Together, the Zooniverse community has helped identify new astronomical objects, classify wildlife imagery, transcribe historical archives, map environmental change and support medical research, contributing to hundreds of scientific publications and discoveries along the way. Each of these billion classifications has helped lead to meaningful change in the world—they have contributed to our collective knowledge of cultural history; to our relationship with our planet; and to our understanding of the universe. 

Some examples of this impact include:

• In 2009, a group of Galaxy Zoo volunteers discovered a new class of small, bright green galaxies (nicknamed “Green Peas”).
• In 2018, the Penguin Watch project provided scientific evidence that led to the Government of South Georgia and the South Sandwich Islands expanding protection for its Marine Protected Area, which contains what is likely the largest colony of penguins on Earth.
• Since 2021, our volunteers have helped translate Zooniverse projects into more than 20 languages (and counting), expanding the potential of our work around the world. Our translators shared that many of them are driven by the desire to help their communities find the same meaning and satisfaction that they get from contributing to real research.
• In 2024, researchers at Lancaster University launched the digital Davy Notebooks collection, which includes more than 13,000 pages of handwritten text from Sir Humphry Davy’s (1778-1829) entire notebook collection, all transcribed by Zooniverse volunteers. This is the first time these documents have been transcribed and annotated in full, and are now publicly available for anyone to access.

The Zooniverse teams at the Adler Planetarium, the University of Oxford, and the University of Minnesota-Twin Cities want to express our overwhelming appreciation for everyone who has ever taken part in a Zooniverse project, whether through classifying, building a project, serving as a Moderator, contributing to conversations on Talk, or sharing projects with friends and family. We could not have reached 1 billion classifications without you.

This milestone belongs to everyone who has contributed their time, attention and expertise over the years. Every classification represents a small act of participation in research and a shared effort to better understand our world and universe together. We’re so proud of our community for reaching 1 billion classifications! We can’t wait to see what incredible discoveries and outcomes the next billion brings.