Yahoo Autos The universe might be shaped like a doughnut, not like a pancake, new research suggests
The universe could, in fact, be a giant doughnut, despite all of the evidence suggesting it's as flat as a pancake, new research suggests.
Strange patterns found in echoes of the Big Bang could be explained by a universe with a more complicated shape, and astronomers have not fully tested the universe's flatness, the study finds.
Related: What shape is the universe?
Flat surfaces
All observations so far suggest the universe is flat. In geometry, "flatness" refers to the behavior of parallel lines as they go out to infinity. Think of a tabletop: Lines that start out parallel will remain that way as they extend along the table length.
In contrast, look at Earth. Lines of longitude begin perfectly parallel to each other at the equator but eventually converge at the poles. The fact that parallel lines initially intersect reveals that Earth is not flat.
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The same logic applies to the 3D universe. For instance, the cosmic microwave background (CMB) — light released when the cosmos was only 380,000 years old — now sits over 42 billion light-years away and features tiny fluctuations in temperature across the sky. Astronomers have calculated the predicted size of those fluctuations compared with observations. If their measured size differs from predictions, that means those rays of light, which started out parallel, changed directions over space-time, indicating that the geometry of the universe is curved.
