A space mission designed to create a three-dimensional map of the universe has just released its first treasure trove of data. And it’s breathtaking: Galaxies of all shapes and sizes seem to be swimming about in a dark cosmic ocean, one peppered with strange circlets of starlight and erupting supermassive black holes.

The team behind Euclid, the European Space Agency telescope in question, has an ambitious goal: to understand the hidden forces glueing the cosmos together and tearing the universe apart. To accomplish this, Euclid’s going to spy billions of galaxies over the next six years—and scientists will use these observations to discern the amorphous nature of the fabric of reality.

(Are We Living in a Black Hole?)

Already, with just seven days of observations from 2024, Euclid has found a staggering 26 million galaxies, along with a host of hundreds of additional bizarre astronomic features. “It’s absolutely mesmerizing,” says Carole Mundell, an astrophysicist and the European Space Agency’s Director of Science.

This is Euclid’s first major salvo of data. Scientists, who are only just beginning to pour over the images it has taken, are starstruck. “The first human reaction is how beautiful they are. They take us out on a journey to the deep cosmos,” says Mundell. “But what has created that is exquisite engineering.”

Here’s how the space telescope’s elegant technology—with some assistance from artificial intelligence—is allowing scientists to shine a light on the dark universe.

What mysteries could Euclid’s data solve?

Two of the biggest questions in astrophysics relate to the nature of dark matter and dark energy, which make up 95 percent of the universe: what, exactly, are they, and why do they affect the cosmos in the way that they do? The former refers to an as-yet undetectable form of matter that keeps galaxies and their stars more tightly bound together than gravity alone can explain. The latter is an unseen force that’s making the expansion of the universe accelerate—though recent measurements of the cosmos suggest that dark energy may be weakening over time.

Scientists cannot (currently) directly detect dark matter or dark energy, so they are doing the next best thing: charting the shape of the cosmos by studying the shapes, motion and positions of many of its galaxies.

That is the grand purpose of Euclid, a European space telescope named, aptly, after a Greek mathematician dubbed the “father of geometry”. Launched in 2023, it sits in a gravitationally stable part of space nearly one million miles away from Earth. While there, it will ultimately study one-third of the entire sky, while repeatedly zooming in on three specific patches of it known as the Euclid Deep Fields—and, as a result, find billions of galaxies.

“Each galaxy is beautiful,” says Adam Amara, an astrophysicist and the UK Space Agency’s chief scientist. “But we didn’t design [Euclid] to produce pretty pictures. We designed it to do hard science.”

(Related: New Space Station Photos Show North Korea at Night, Cloaked in Darkness)

Ideally, telescopes have wide fields-of-view (so they can see big patches of the sky), high resolution vision (so fine details pop out of photographs) and high sensitivity, so even the faintest, most distant starlight can be detected. “We can usually choose two out of those three. And for the first time ever, Euclid is giving us all three,” says Mundell. “I think that’s the real power of the telescope.”

A dark universe toolkit

Euclid’s galaxy-hunting prowess comes down to just three tools. The first is its four-foot-long telescope, whose mirror captures distant starlight before a prism-like filter splits it into visible and infrared light, passed onto two specialized devices.

One is the VISible instrument, effectively a very sensitive camera with a 600-megapixel resolution—50 times better than many contemporary smartphones. Thanks to a very wide field-of-view, and the ability to take extremely long exposures of deep space, it can spot billions of galaxies at remarkable distances, clearly revealing their shapes and idiosyncrasies.

(Related: SpaceX Wants to Go to Mars. Here’s Why Humans Aren’t There Yet.)

“Euclid has already taken images of several times more sky than Hubble did in 25 years,” says Mike Walmsley, a machine learning researcher focused on astronomy, and Euclid Consortium scientist, based at the University of Toronto, Canada.

The second device is the Near-Infrared Spectrometer and Photometer, another ultra-sensitive camera that captures infrared light and can, among other things, measure how distant galaxies are from Earth. And when overlayed atop Euclid’s visual light images, scientists hope to generate a three-dimensional map of the universe as they get more data.

“It’s really the combination of these two instruments that allows us to then test dark energy,” says Valeria Pettorino, a physicist and the European Space Agency’s Euclid project scientist.

The universe is 13.8 billion years old. Euclid’s technical wizardry allows it to see galaxies that formed as far back as 10.5 billion years ago. That means that “Euclid is not only a dark universe detective,” says Mundell. “It’s also a time machine.”

What kinds of galaxies did Euclid find?

Among the millions of galaxies that Euclid has documented are a suite of far-flung quasars, galaxies whose supermassive black hole cores are dazzlingly bright. “Euclid’s images are so sharp—about five times sharper than from the ground—that we have a totally new view of galaxies,” says Walmsley.

Other phenomena in Euclid’s data that cosmologists obsess over are gravitational lenses. Sometimes, when something massive—say, a galaxy with plenty of dark matter—sits in front of another more distant galaxy, the light from that distant galaxy is warped around the foreground galaxy, as if focused by a lens.

(Related: See galaxy photos from National Geographic)

This process is known as gravitational lensing and can reveal distant galaxies that would have otherwise been invisible even to telescopes like Euclid. In rare cases, the ancient light that warps around the foreground galaxies can form distinct light features known as strong lenses.

Before Euclid, and after decades of modern observations of the night sky, about 1,000 strong lenses had been identified by astronomers. “In a few days, Euclid comes out and finds 500, just like that,” says Amara. “That’s mind-blowing.

Euclid’s image of a galaxy called NGC 6505 captures an example of a strong lens called an Einstein ring, where the light forms a circle around the distant object. These powerful lenses are thought to be great ways to understand dark matter, as the light’s contortion can hint at how much as-yet imperceivable dark matter is present in the foreground galaxy.

Amara expects it to find hundreds of thousands of strong lenses over the next six years, along with many examples of weak gravitational lensing.

Using AI to navigate an ocean of galaxies

The sheer number of resplendent astrophysical objects overwhelmed the Euclid team. “Once we’ve got over that sense of wonder and magic and just breathtaking awe, then you start to think: One astrophysicist can’t interrogate millions and millions of galaxies,” says Mundell. “And that’s where AI has come in.”

Artificial intelligence programs are very good at recognizing patterns. One such program, named ZooBot, has been deployed to help Euclid scientists classify galaxies. Recently, around 10,000 human volunteers were presented with images of galaxies, then asked to filter them into boxes based on their shapes and features. ZooBot was then trained on this data and then unleashed on Euclid’s week of observations.

(Related: 5 famous constellations that (almost) anyone can find)

“It would take about 150 years to look through every reasonably-sharp galaxy” in the new set of Euclid images,” says Walmsley. But at lightning speed, ZooBot has categorized more than 380,000 galaxies based on their shapes, sizes and features.

There is considerably more to come, and Euclid is already delivering. “We are receiving more than 100 gigabytes of data per day,” says Pettorino. “At the end of 2026, we have to release one year of observations for a total of more than two petabytes, which is the equivalent of 31 years of you watching TV with the best video streaming.”

The author Douglas Adams once famously wrote: “Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is.” And that remains true. But Euclid is turning this expansive void into a technicolor canvas brimming with galaxies.

“There’s only a finite amount of sky,” says Amara. “And we’re starting to fill it all in.”