The Wine Glass Trick That Explains a Cosmic Phenomenon
Hold a wine glass up to a candle. The flame stretches into arcs and rings, bent by the glass’s curve. Now imagine replacing the glass with a galaxy cluster—a massive collection of matter—and the candle with a distant galaxy billions of light-years away. What you observe is gravitational lensing: light following the warped fabric of spacetime around massive objects, a phenomenon predicted by Einstein’s general relativity.
When the alignment is precise, background galaxies appear distorted into luminous arcs or complete rings, known as Einstein rings. These are not optical illusions but real distortions caused by the universe bending light. For astronomers, they serve as natural telescopes, allowing the study of galaxies that would otherwise remain too faint or obscured to observe directly.
Spotting these lenses, however, is challenging. The distortions can be faint, irregular, or lost in background noise. The European Space Agency’s Euclid telescope, launched in 2024, is designed to address this. It is surveying the sky with remarkable sensitivity, capturing images of 72 million galaxies in its first year. This dataset presents a vast opportunity for lens hunters, though its scale requires innovative approaches to analysis.
Why AI Needs Human Eyes (And How You Can Help)
Artificial intelligence has already processed Euclid’s data, identifying 300,000 candidate images for further examination. Yet AI has limitations. While it excels at pattern recognition, it often struggles with irregular or ambiguous cases—precisely the kinds of features human eyes can detect. This is where the Space Warps project comes in.
Hosted on Zooniverse, the world’s largest citizen science platform, Space Warps invites the public to participate in the search. Volunteers are shown images from Euclid and asked to mark anything resembling a gravitational lens. A glowing arc? A faint smear? A near-perfect ring? The platform’s interface is user-friendly, with a tutorial guiding participants and a voting system to refine results.
The project is not just about quantity. In early 2025, researchers analyzed a small fraction of Euclid’s data and identified 500 new lenses, many previously unknown. Scaling this effort, officials have suggested the project could significantly increase the number of known lenses. For comparison, this would represent a substantial expansion over the total discovered in the history of astronomy.
Aprajita Verma, co-founder of Space Warps and a project lead at the University of Oxford, noted that the latest dataset is far larger than previous searches and that improved AI algorithms are expected to yield thousands of high-quality lens candidates. The volume of data makes collaboration essential. Euclid transmits roughly 100 gigabytes of data to Earth daily, a scale no single team or institution can manage alone.
The Scientific Payoff: Weighing the Invisible
Why does this effort matter? Gravitational lenses are more than visually striking—they are powerful scientific tools. By analyzing how light bends around them, researchers can measure the mass of lensing galaxies and galaxy clusters, mapping the distribution of both visible and dark matter. This provides clues about the universe’s expansion and the role of dark energy, which remains one of cosmology’s greatest mysteries.
Euclid’s primary mission is to investigate dark matter and dark energy, which together comprise most of the universe. Weak gravitational lensing and other techniques are central to this effort, but strong gravitational lenses—like the arcs and rings Space Warps is targeting—offer a complementary approach. They function as precision instruments, revealing the mass of lensing objects with high accuracy.
For participants, the project offers a unique opportunity to engage with cutting-edge science. The chance to contribute to discoveries, such as identifying a new Einstein ring, is a key motivation. Additionally, projects like Space Warps make astronomy more accessible, transforming it from a passive field into an interactive endeavor. This model has proven successful in the past. SETI@home, for example, demonstrated how distributed human effort could tackle problems too complex for machines alone. Space Warps applies a similar principle to visual data analysis.
How to Join the Hunt (And What You Might Find)
Getting involved is simple. Visit the Space Warps project page on Zooniverse. After a brief tutorial, you’ll be presented with images from Euclid’s dataset. Your task is to look for arcs, rings, or distortions that suggest a gravitational lens. The platform provides examples to guide your search, and if multiple users flag the same image, it advances for professional review.
What might you discover? The possibilities vary. Some findings may be false positives, such as galaxy mergers that resemble lenses. Others could be groundbreaking—a new Einstein ring or a lens so massive it reveals a galaxy from the early universe. In 2024, the first Space Warps campaign identified hundreds of lenses in a fraction of Euclid’s data. With the full dataset now available, the potential for significant findings has increased.
The project also highlights the strengths of human-AI collaboration. AI narrows the dataset from 72 million galaxies to 300,000 candidates, but the final evaluation relies on human judgment. This underscores that even in an era dominated by machine learning, some tasks still benefit from human intuition and curiosity.
What’s Next: The Data Deluge and the Limits of Automation
Euclid’s mission is ongoing. The telescope will continue surveying the sky for at least six years, with each new data release promising more galaxies—and more lenses—to examine. The challenge lies not only in finding these lenses but in managing the vast amount of data generated. A hundred gigabytes daily accumulates quickly, and even advanced AI has its limits.
This is where citizen science proves invaluable. Projects like Space Warps do more than supplement professional research; they redefine what is achievable. In 2016, volunteers on Zooniverse’s Galaxy Zoo project discovered a new class of galaxies—“green peas”—that had escaped automated detection. In 2020, another group helped identify a rare type of gravitational lens. These examples demonstrate that when equipped with the right tools, the public can contribute in ways algorithms cannot.
For now, the focus remains on Euclid’s first-year dataset. The 300,000 pre-filtered candidates await analysis, and time is a factor. Each lens discovered brings researchers closer to understanding dark matter, dark energy, and the fundamental forces shaping the universe. With thousands of new lenses within reach, the next major discovery could come from anyone—a hobbyist astronomer, a curious student, or an enthusiast working from home.
One certainty remains: the universe is bending light in remarkable ways. The question is, who will be the next to spot it?
