The universe is flat, but what does that really mean?

The BOSS telescope mapped 1.2 million galaxies with 99% accuracy, revealing a flat cosmos.

Key Takeaways

Scientists have determined the universe is “flat,” but it’s more complex than it seems.
A flat universe means parallel lines of light remain parallel indefinitely, suggesting infinity.

The BOSS telescope mapped 1.2 million galaxies, showing the universe extends infinitely in time and space.
Geometric flatness doesn’t reveal the universe’s topology, which may have complex shapes like a Möbius strip.
Light behavior and galaxy observations imply the universe is extraordinarily vast and interconnected.

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For years, scientists have debated the shape of the universe. Recent findings suggest the universe is “flat” — but the term carries a unique meaning. Using data from the Baryon Oscillation Spectroscopic Survey (BOSS) telescope, astrophysicists have determined that parallel lines of light observed from distant galaxies remain parallel indefinitely, supporting the flatness concept.

The BOSS telescope, based in New Mexico, provided an incredibly accurate map of 1.2 million galaxies. This precise mapping enabled cosmologists to conclude that the universe is not just geometrically flat but also potentially infinite, extending indefinitely in both space and time. David Schlegel, a physicist from Lawrence Berkeley National Laboratory, explained that while infinity can’t be proven, the findings strongly align with an infinite universe.

A flat universe implies that space follows Euclidean geometry — where parallel lines do not converge or diverge. By observing light from galaxies, researchers noted that these beams stayed parallel over vast distances, supporting the flatness hypothesis. This geometric flatness contrasts with curved universes, where space would warp and parallel lines would eventually meet.

Diagrams of three possible geometries of the universe: closed, open and flat from top to bottom. The closed universe is of finite size and, due to its curvature, traveling far enough in one direction will lead back to one’s starting point. The open and flat universes are infinite and traveling in a constant direction will never lead to the same point. Image and caption text permission of NASA Official: Gary Hinshaw

Beyond Geometry: The Topology Question

While the universe’s flat geometry is well-established, its topology remains an enigma. Scientists believe the universe could take on one of 18 potential shapes, ranging from simple forms to complex configurations like a Möbius strip. In such a topology, space could bend and connect, meaning you could theoretically travel in a straight line and end up where you started.

This concept raises profound questions about the universe’s structure. A flat universe doesn’t necessarily contradict a finite cosmos — it only suggests that, on a large scale, space doesn’t curve in ways that would make parallel lines intersect. However, limitations in our observational reach prevent scientists from determining whether the universe is truly infinite or looping back on itself in an exotic shape.

The results from the BOSS telescope offer groundbreaking insights into the universe’s geometry, but the quest to uncover its complete topology continues. For now, the flat, infinite cosmos provides a fascinating canvas for exploring existence and the potential interconnectedness of everything within it.