On March 11, 2025, something extraordinary happened. As most of us went about our daily routines here on Earth, NASA launched its newest space telescope into orbit, quietly setting in motion a mission that could forever change our understanding of where we come from. Meet SPHEREx—an ambitious, highly sophisticated explorer of the cosmic dawn, set to peer deeper into the origins of the universe than any mission before.
This isn’t just another space telescope looking for pretty pictures of galaxies. SPHEREx—short for Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer—is on a two-year mission to answer some of the most profound questions humans have ever asked: What happened in the first trillionth of a second after the Big Bang? How did the universe go from a soup of energy to stars and galaxies? And, where might life as we know it find a foothold beyond Earth?
At the heart of this mission lies a collaboration between NASA and a network of scientific institutions that includes the University of Arizona’s Arizona Cosmology Lab. Working alongside Caltech, NASA’s Jet Propulsion Laboratory, Ball Aerospace, and the Korea Astronomy and Space Science Institute, these researchers have developed cutting-edge software and machine learning tools that will turn SPHEREx data into insights about the birth and evolution of the cosmos.
Peering into the Infancy of the Cosmos
SPHEREx’s objectives are as ambitious as they are fascinating. Over the next two years, this space-based observatory will sweep the sky in optical and infrared wavelengths, compiling an unprecedented 3D map of more than 450 million galaxies and 100 million stars within our own Milky Way.
What’s special about SPHEREx is its whole-sky survey approach. Unlike missions that focus on small patches of space, SPHEREx will scan the entire sky multiple times over its mission. Think of it as creating the ultimate cosmic census—mapping stars and galaxies across time and space, charting where they are now and providing clues about where they came from.
One of SPHEREx’s primary targets? The inflationary epoch, that mind-bending moment shortly after the Big Bang when the universe expanded faster than the speed of light. We’re talking about a cosmic event that happened in less than a blink—an expansion that took the universe from subatomic to galactic scales in a fraction of a second.
“Inflation left faint fingerprints all over the universe,” explains Elisabeth Krause, associate professor of astronomy and physics at the University of Arizona, and leader of the SPHEREx team there. “By creating the largest 3D map of galaxies ever made, SPHEREx can reveal those imprints, helping us understand the earliest processes that shaped everything we see today.”
These fingerprints are subtle distortions in how galaxies are distributed across the cosmos—echoes of the quantum fluctuations that were magnified by inflation and later grew into galaxies, stars, and eventually planets. SPHEREx’s infrared vision is perfectly tuned to detect these distributions.
Dark Matter and the Unseen Universe
But SPHEREx isn’t just chasing ancient echoes. It’s also mapping dark matter, the mysterious invisible substance that makes up about 85% of the matter in the universe.
While dark matter can’t be seen directly, its presence can be inferred from how galaxies cluster together. “Galaxies are like breadcrumbs,” says Tim Eifler, associate professor of astronomy at the University of Arizona’s Steward Observatory. “They trace where dark matter is hiding. Where we find dense clusters of galaxies, we know dark matter is shaping the landscape through gravity.”
By tracking these galactic breadcrumbs on an unprecedented scale, SPHEREx could help researchers finally zero in on the elusive nature of dark matter—what it is, how it behaves, and how it has influenced the cosmos for billions of years.
Water Ice and the Search for Life
Closer to home, SPHEREx will also turn its gaze inward, toward the Milky Way. One of its key goals is to search for water ice on dust grains surrounding young stars and in the regions where new planets are forming.
Water ice is a critical ingredient in the recipe for life. By studying where water ice exists in the galaxy, SPHEREx will help scientists better understand where the conditions for life might be found beyond Earth.
“Finding water ice around stars is like finding the key ingredient in a recipe for habitability,” Krause says. “It gives us important clues about where to look for potentially habitable exoplanets.”
Cracking the Cosmic Code with Machine Learning
The sheer amount of data SPHEREx will collect is staggering. Imagine a cosmic phone book listing hundreds of millions of galaxies, with information on their position, brightness, and chemical composition. Processing all this information and making sense of it is where the Arizona Cosmology Lab comes in.
Former U of A postdoctoral student Yosuke Kobayashi developed a complex mathematical model capable of filtering SPHEREx’s galaxy data, separating the cosmic wheat from the chaff. His model pinpoints the essential features in galaxy clustering while discarding less relevant noise—an essential step in understanding the universe’s inflationary origins.
But developing equations is one thing—turning them into high-speed, intelligent software is another. To bridge that gap, the Arizona Cosmology Lab turned to machine learning and neural networks to accelerate data processing.
“Computational speed has always been a bottleneck when predicting what we see in the universe,” Eifler explains. “Now we’re training a neural network to take these complex equations and make them run much, much faster. What used to take days or weeks can now be done in hours.”
Thanks to the University of Arizona’s state-of-the-art high-performance computing system, these massive calculations are possible. The lab’s neural networks will help crunch the data coming from SPHEREx, revealing patterns that will refine cosmological models and test bold new theories about the origins of space and time.
The Dawn of a New Era in Cosmology
Once SPHEREx settles into its orbital routine and begins transmitting data back to Earth, the Arizona Cosmology Lab’s work will enter its most exciting phase. The team will sift through mountains of information, seeking to constrain cosmological models and answer the ultimate question: What happened at the very beginning?
Will SPHEREx confirm current models of cosmic inflation, or will it find unexpected anomalies that challenge what we think we know? Could it uncover new clues about dark matter’s nature, or shed light on where the universe is headed next?
For Krause, Eifler, and their colleagues, the possibilities are thrilling. “This is why we do what we do,” Krause says. “SPHEREx gives us a new lens to look at the deepest questions about existence.”
A Telescope for Everyone
One of the most exciting aspects of SPHEREx is that its data will be public. Scientists across the world will have access to this cosmic treasure trove, enabling them to explore their own questions and make new discoveries.
By scanning the entire sky in both the visible and infrared, SPHEREx is collecting a data set that will serve not just its mission goals, but a whole generation of astronomers and astrophysicists.
“This is a telescope for everyone,” Krause says. “Whether you’re studying galaxies at the edge of the universe or icy bodies in our solar system, SPHEREx will have something for you.”
Why It Matters
In the grand scheme of things, understanding the first trillionth of a second after the Big Bang might seem esoteric. But these insights ripple through everything—from how we understand fundamental physics, to how we frame our place in the universe.
SPHEREx is not just a telescope. It’s a time machine, a detective, and a cosmic cartographer all rolled into one. It’s a mission that could tell us not only where we came from, but also where we might be going.
As SPHEREx embarks on its journey, our species takes another step toward answering questions that have haunted humanity for millennia: What is our place in the cosmos? How did it all begin?
And thanks to this small, unassuming satellite quietly orbiting above us, we may soon know a little more about the answer.