Our galaxy is not sitting still. Along with thousands of others, the Milky Way is being pulled across space toward something vast — and astronomers have just discovered that the “something” is far bigger than anyone realised.
The finding reshapes our sense of home. It suggests the boundaries we drew around our corner of the universe were far too modest, and that our galaxy is bound into a flow of truly cosmic proportions.
A team led by researchers at the University of Hawaiʻi has identified a colossal cosmic structure called a Basin of Attraction. It may be roughly ten times larger than Laniakea, the supercluster our galaxy was thought to belong to.
If confirmed, it means the Milky Way may not live where we thought it did — and that the universe is organised on scales larger than our best models comfortably allow.
This article explains what a Basin of Attraction is, how it was mapped, why it challenges cosmology, and what it reveals about our place in the cosmic web.
What Was Discovered
The research, published in the journal Nature Astronomy, drew on the motions of more than 56,000 galaxies to trace how matter flows through the nearby universe.
By mapping which direction galaxies are drifting, the team identified enormous regions where everything flows toward a shared gravitational centre. These regions are the basins of attraction.
The striking result is that our own basin appears far larger than expected. Rather than being anchored by the local Laniakea Supercluster, our galaxy may be caught in the pull of the distant Shapley Concentration.
The team estimates roughly a sixty percent probability that the Milky Way belongs to this much larger Shapley-centred basin — a structure about ten times the volume of Laniakea.
Our Cosmic Address
To grasp the scale of this discovery, it helps to zoom outward step by step. Each level of structure dwarfs the last.
Earth orbits the Sun. The Sun is one of hundreds of billions of stars in the Milky Way galaxy, itself a spiral roughly 100,000 light-years across.
The Milky Way belongs to the Local Group, a small cluster of galaxies bound by gravity, dominated by ourselves and the Andromeda galaxy.
The Local Group sits within the larger Virgo Supercluster, which in turn was found to be a lobe of the far greater Laniakea Supercluster.
Now the new work adds another level above them all — a basin of attraction that may contain Laniakea itself as merely one of its parts.
What Is a Basin of Attraction?
The term is borrowed from the mathematics of flowing systems. Imagine rain falling across a landscape: every drop eventually drains toward one river valley, defined by the surrounding hills.
A cosmic basin of attraction works the same way, but with gravity instead of gravity-fed rivers. Galaxies within a basin all drift toward a common gravitational low point.
These flows are gentle but relentless. On top of the overall expansion of the universe, galaxies carry small extra motions — called peculiar velocities — steered by the gravity of nearby mass.
Reading those peculiar velocities is how astronomers map otherwise invisible structure. The direction a galaxy leans reveals where the mass — including dark matter — is concentrated.
A basin’s edges are the cosmic “watersheds” where flows split, some draining one way and some another. Defining those boundaries is how the team measured the true size of our home structure.
It is a subtle shift in thinking. A structure is defined not by a visible wall of galaxies, but by the invisible territory over which a single centre of gravity holds sway.
The Great Attractor and the Shapley Concentration
For decades, astronomers have known that the Local Group of galaxies is racing through space at about 600 kilometres per second toward an unseen mass.
They named this pull the Great Attractor — a gravitational anomaly whose full nature was hidden partly behind the dust of our own Milky Way, in the so-called Zone of Avoidance.
The new work suggests the Great Attractor is not the final destination. It appears to be a way station on a larger flow toward the Shapley Concentration, far beyond it.
The Shapley Concentration is the largest known collection of galaxies in the nearby universe — a titanic overdensity of clusters lying several hundred million light-years away.
If our galaxy is truly falling toward Shapley, then the Great Attractor and Laniakea are merely features within a far grander basin — one we are only now beginning to trace.
The Zone of Avoidance
Part of why these structures took so long to map is an obstacle in our own backyard. The dense band of the Milky Way blocks our view of whatever lies directly behind it.
Astronomers call this obscured strip the Zone of Avoidance. Dust and stars hide roughly a fifth of the extragalactic sky from optical telescopes.
The Great Attractor happens to lie partly within this zone, which is why its true nature stayed mysterious for so long after its pull was first detected.
Radio and infrared observations, which pierce dust more easily, have gradually filled in the gaps — and mapping galaxy flows offers another way to sense mass we cannot directly see.
Are We Not in Laniakea After All?
In 2014, the same broad research group defined the Laniakea Supercluster — a structure some 500 million light-years across, containing about 100,000 galaxies, including ours.
Laniakea, a Hawaiian word meaning “immense heaven,” was itself a landmark. It redrew our cosmic address by defining the supercluster as the basin our galaxy flows within.
The new findings suggest that boundary may have been drawn too small. With more galaxy data, the flows appear to extend well beyond Laniakea’s original edge.
This does not erase Laniakea. It suggests Laniakea may be a sub-region of something bigger, in the same way a valley is part of a wider river system.
The honest position is one of uncertainty. The probability is around sixty percent that we belong to the larger Shapley basin — strong, but not yet a settled fact.
How Astronomers Mapped It
The map comes from a project called Cosmicflows, which has spent years compiling precise distances and velocities for tens of thousands of galaxies.
Measuring a galaxy’s distance independently of its redshift is difficult, but it is the key step. Comparing the two reveals the peculiar velocity — the part of the motion driven by gravity rather than cosmic expansion.
From tens of thousands of these velocity vectors, the team reconstructed the underlying gravitational landscape — the hidden hills and valleys of mass shaping the flows.
Because most of that mass is dark matter, this method effectively maps the invisible. The visible galaxies are just tracers, floating along currents set by unseen gravity.
The same principle underlies other ways of weighing the dark universe, such as the light-bending technique described in our article on gravitational lensing.
A Century of Mapping the Universe
The story of this discovery is really the story of a century-long effort to chart the universe’s large-scale structure.
In the 1920s, Edwin Hubble showed that galaxies exist far beyond the Milky Way and that they are rushing apart, revealing an expanding cosmos.
By the late twentieth century, redshift surveys had exposed the cosmic web — the filaments and voids that give the universe its foamy, structured appearance.
The leap in recent years has been measuring not just where galaxies are, but how they move. Velocity maps turn a static picture into a dynamic one.
The Basin of Attraction is the fruit of that shift — the moment cartography of the cosmos became a study of cosmic currents, not just cosmic coastlines.
The Cosmic Web
Zoom out far enough and the universe is not a random scatter of galaxies. It is a vast network astronomers call the cosmic web.
Galaxies gather along immense filaments of matter, like beads on threads. Where filaments cross, they build dense superclusters. Between them lie enormous, near-empty voids.
Basins of attraction are the large-scale flow patterns woven through this web. They describe not just where matter is, but where it is going.
Understanding the web this way — as a system in motion — is what allowed the team to define a basin’s true boundaries rather than just its brightest clusters.
The new results suggest the web is even more interconnected than thought, with galaxies coordinated across distances that strain our sense of what counts as a single structure.
How Big Is “Big”?
Numbers on this scale lose meaning quickly, so a comparison helps. Light from the far side of Laniakea set out around the time our earliest human ancestors were emerging.
A structure ten times larger stretches across a span light takes hundreds of millions of years to cross — far longer than complex life has existed on Earth.
Yet even this is small against the whole observable universe, which spans some 93 billion light-years. A basin of attraction is vast, but it is still a local feature.
That perspective is humbling and clarifying at once. What we call our cosmic neighbourhood is, on the largest scales, barely a single grain in an unimaginable expanse.
Other Giant Structures in the Universe
The Basin of Attraction joins a growing catalogue of enormous structures that push the limits of what cosmology expects.
Astronomers have reported features such as the Sloan Great Wall, a sheet of galaxies over a billion light-years long, and even larger candidate structures traced by distant quasars.
Some of these claimed structures remain debated, precisely because they test the assumption that the universe smooths out on large scales. Distinguishing real structure from chance alignment is subtle work.
What sets the Basin of Attraction apart is that it is defined by motion, not just position. It is a structure we detect by how it moves matter, which makes it especially compelling evidence.
The Role of Dark Matter
Dark matter makes up about twenty-seven percent of the universe and provides most of the gravity holding large structures together.
The basins of attraction are, in effect, dark matter’s fingerprints. The galaxies we see are lit signposts, but the invisible mass is what actually sculpts the flows.
Mapping these enormous basins therefore tests our models of how dark matter is distributed on the very largest scales — and whether it clumps as expected. The substance itself is explored in our article on dark matter, the invisible universe.
There is a deeper implication too. If the basins are larger than models predict, it may mean dark matter is more strongly clustered on huge scales than the standard picture allows — a subtle but important clue.
The Role of Dark Energy
If dark matter pulls structures together, dark energy pushes the universe apart, driving its accelerating expansion.
The two are locked in a cosmic tug-of-war. Gravity builds basins and superclusters; dark energy stretches the space between them ever faster.
Over cosmic time, dark energy is winning. Eventually it may pull these great basins apart faster than gravity can assemble them, isolating each structure in the dark.
Mapping today’s flows captures a snapshot of that struggle — a balance point in a contest that will ultimately shape the universe’s fate. The repulsive side is explored in our article on dark energy, the invisible force.
This gives the discovery a poignant edge. The grand basin we are only now mapping is, in the deep future, destined to be pulled beyond reach as space expands.
In a sense, we are charting our cosmic neighbourhood at the very moment cosmic history allows it — before dark energy carries its distant reaches over the horizon forever.
Why This Challenges Cosmology
A cornerstone of modern cosmology is the assumption that, on large enough scales, the universe looks the same everywhere. This is called the cosmological principle.
Standard models predict that above a certain “homogeneity scale,” structures should smooth out. Extremely large, coordinated flows are not supposed to be common.
A basin ten times the size of Laniakea sits uncomfortably against that expectation. It hints that structure may extend to larger scales than the simplest models allow.
This does not overturn the Big Bang or the broad framework of cosmology. But it joins a growing list of large-scale puzzles hinting that our picture is incomplete.
Those puzzles include the disagreement over the universe’s expansion rate, explored in our article on the Hubble tension.
What Comes Next
Confirming the basin’s full extent will require far more galaxy data, and a new generation of instruments is arriving to provide it.
The Vera C. Rubin Observatory will survey the entire southern sky repeatedly, cataloguing billions of galaxies and sharpening our maps of cosmic flows.
The European Euclid space telescope is charting the distribution of galaxies and dark matter across billions of years of cosmic history.
The Square Kilometre Array, a giant radio observatory under construction, will detect hydrogen in distant galaxies, extending velocity maps deeper into space than ever before.
Together, these surveys should settle whether our galaxy truly belongs to the Shapley basin — and reveal how many other giant basins thread the nearby universe.
A Discovery Built on Uncertainty
One of the most honest aspects of this research is how openly it states its own limits. The team does not claim certainty — it reports a probability.
That roughly sixty percent figure is itself a scientific statement. It says the evidence favours the larger basin, while acknowledging that current data cannot yet prove it.
This is how frontier cosmology works. Conclusions are drawn from incomplete maps, then refined as better data arrives, with the uncertainty stated plainly rather than hidden.
Far from weakening the result, that candour is its strength. It tells us exactly what to test next, and how confident we are allowed to be today.
Why This Discovery Matters
Every so often, astronomy redraws the map of where we live. The Basin of Attraction is one of those moments.
It suggests our cosmic address is larger and stranger than we knew — that the Milky Way is part of a flow spanning hundreds of millions of light-years.
It also demonstrates a powerful method: reading the faint drift of galaxies to weigh mass we cannot see, and to expose structure larger than any single telescope could image.
The deep-sky instruments driving this work are the same ones reshaping astronomy across the board, as covered in our article on the James Webb Space Telescope.
Most of all, it is a reminder of scale. We are passengers on a small planet, in a modest galaxy, drifting on a current so vast we have only just begun to chart its shores.
Each time we think we have measured our place in the cosmos, the map turns out to be a detail of something larger. The Basin of Attraction is the latest such humbling — and almost certainly not the last.
For now, the takeaway is simple to state and hard to fully absorb. The Milky Way is drifting, along with thousands of galaxies, toward a gravitational heart we are still working to locate.
Understanding that motion is how we learn the true architecture of the universe — and, in doing so, exactly where in it we belong.
Frequently Asked Questions
What is the Basin of Attraction?
A Basin of Attraction is a vast region of space where the collective gravity of matter causes galaxies to flow toward a common centre, much like rainfall draining into a single valley. Astronomers using the motions of over 56,000 galaxies found that our galaxy may sit in a basin about ten times larger than the Laniakea Supercluster, likely centred on the distant Shapley Concentration.
How large is it compared to Laniakea?
The newly identified basin is estimated to be roughly ten times the volume of the Laniakea Supercluster. Laniakea, defined in 2014, spans about 500 million light-years and contains around 100,000 galaxies — so the new structure is truly enormous.
Does this discovery contradict the Big Bang?
No. It refines our understanding of how large-scale structure forms but does not challenge the overall framework of Big Bang cosmology. It does, however, sit in tension with the assumption that the universe becomes smooth and uniform above a certain scale — a point worth further investigation.
Are we still part of the Laniakea Supercluster?
Possibly not, in the way we thought. The new analysis gives around a sixty percent probability that the Milky Way actually belongs to the larger Shapley basin rather than Laniakea. Laniakea would then be a sub-region of a much bigger structure. More data is needed to confirm this.
What caused this structure to form?
It is the result of gravity acting over billions of years on immense concentrations of dark matter and ordinary matter. Slightly denser regions in the early universe pulled in surrounding material, growing into the superclusters and vast flows we map today. Dark matter provides most of the gravitational pull involved.
How do astronomers map invisible structures like this?
They measure the peculiar velocities of galaxies — the small motions caused by gravity on top of the universe’s overall expansion. By comparing each galaxy’s independently measured distance with its redshift, researchers reconstruct the hidden landscape of mass, most of which is invisible dark matter, and trace the flows it drives.
Further Reading
Sources
- Valade, A., Libeskind, N. I., Pomarède, D., Tully, R. B., et al. (2024). “Identification of basins of attraction in the local Universe.” Nature Astronomy (DOI: 10.1038/s41550-024-02370-0).
- Tully, R. B., Courtois, H., Hoffman, Y. & Pomarède, D. (2014). “The Laniakea supercluster of galaxies.” Nature, 513, 71 (DOI: 10.1038/nature13467).
- University of Hawaiʻi at Mānoa — Institute for Astronomy news releases.
- Cosmicflows Project — galaxy distance and velocity data.
Baryon. (2025, February 18). Astronomers Discover New Cosmic Structure, Challenging Our Understanding of the Universe. Web News For Us. https://webnewsforus.com/astronomers-discover-new-cosmic-structure/
Baryon. “Astronomers Discover New Cosmic Structure, Challenging Our Understanding of the Universe.” Web News For Us, 18 February 2025, https://webnewsforus.com/astronomers-discover-new-cosmic-structure/. Accessed 10 July 2026.
