Astronomers have commissioned more than 10,000 amateur scientists from 85 countries to assist in their ambitious mission in an unprecedented effort to map galaxies. Having set its sights on a groundbreaking project to uncover the mysterious properties of dark energy, the team is now looking for ways to further expand its volunteer power. This groundbreaking effort could potentially shed light on one of our universe’s greatest mysteries.

The research project, known as HETDEX or the Hobby-Eberly Telescope Dark Energy Experiment, is based at the University of Texas at Austin’s McDonald Observatory and is based on volunteers participating in an online project called Dark Energy Explorers. Using a smartphone or computer, participants can experience what it’s like to become an astronomer, solve the mysteries of the universe, help professional astronomers find distant galaxies, and learn more about the mysterious force known as dark energy that causes the universe to expand rapidly.

Humans are better than machines at picking out real galaxies from images like this one from the Dark Energy Explorers project. Credit: Since the University of Texas at Austin Dark Energy Explorers launched in February 2021, more than 10,000 volunteers have identified nearly 240,000 galaxies. That’s about one-tenth the number of galaxies that researchers hope to eventually find when examining an area of ​​sky the size of about 2,000 full moons, which includes most of the Ursa Major.

“That’s why we need more people,” said Karl Gebhardt, professor of astronomy and a project scientist and HETDEX principal investigator at UT Austin. “If we can reach 100,000 volunteers around the world, which I think is possible, then next year we’ll hit the ground running.”

Dark Energy Explorers is sponsored by Zooniverse, the world’s largest amateur science organization. Users join via the Zooniverse website or the Zooniverse smartphone app (available for iOS and Android). Members can create a free account and then select Dark Energy Explorers from a list of projects.

After a short training session, the volunteers look at the astronomical images and decide whether the objects they see are galaxies or random noise; this is a distinction that even the most advanced software has a lot of trouble detecting. Volunteers then swipe left or right to indicate whether a galaxy is depicted.

“It’s really interesting to see how enthusiastic the public is about classifying these galaxies,” said Lindsay House, a graduate student at the University of Austin who led the project.

The goal is to create the largest 3D map of the cosmos, focusing on galaxies in the early universe to help uncover important clues about dark energy.

A large-scale research project was designed to explore whether dark energy changes or is constant over time. It is believed that at least two-thirds of the universe consists of dark energy, but scientists know very little about it. Understanding how dark energy behaves is an important first step towards understanding what it is, but astronomers need a large sample of distant galaxies to observe dark energy. That’s what HETDEX is, a large-scale survey of more than a million distant galaxies using one of the world’s largest optical telescopes, the 11-metre Hobby-Eberly Telescope at the McDonald Observatory in West Texas.

Dark Energy Explorer volunteers review images from HETDEX, helping to reduce the time astronomers spend on the mission by 90%. This way, professionals can focus their energies on the toughest classifications.

“We tried to write computer code for this and even used machine learning, but we found that the human eye is much better,” said Gebhardt. “We were skeptical at first, but impressed by its accuracy.”

It took 3.75 million movements of volunteers to identify 247,000 galaxies. Many more scans are required than galaxies, as each candidate galaxy is viewed by around 15 people to help reach consensus and improve accuracy.