2016年12月7日 · What does it mean for a 3D object to be "flat"? How do we measure the shape of the universe anyway? Since the universe is flat, is that…it? Is there anything else interesting to say?

In geometry, a flat is an affine subspace, i.e. a subset of an affine space that is itself an affine space. [1] Particularly, in the case the parent space is Euclidean, a flat is a Euclidean subspace which inherits the notion of distance from its parent space.

As of 2024, current observational evidence suggests that the observable universe is spatially flat with an unknown global structure. The curvature is a quantity describing how the geometry of a space differs locally from flat space.

2021年2月23日 · As far as cosmologists can tell, space is almost perfectly flat. But what does this mean? The theory of general relativity, under which space itself can curve, allows for the universe to take one...

2024年11月22日 · 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.

2022年5月31日 · In theory, the fabric of space could have been curved in any way imaginable. So why is the Universe flat when we measure it? In a hypertorus model of the Universe, motion in a straight line...

2023年8月23日 · "Flat space" means that on large scales, Euclidean geometry holds. All the angles in any triangle drawn in space add up to 180°; the total distance between points separated by $\Delta x$, $\Delta y$, and $\Delta z$ is $d=\sqrt{\Delta x^2+\Delta y^2+\Delta z^2}$; et cetera.

2023年8月4日 · Therefore, when scientists talk about a “flat” universe, they refer to the curvature of the universe’s space, not that the universe has the shape of a flat pancake or anything of that sort.

2017年6月7日 · In fact, astronomers estimate that the universe must have been flat to 1 part within 1×10 57 parts. Which seems like an insane coincidence.

In cosmology, flatness is a property of a space without curvature. Such a space is called a "flat space" or Euclidean space [citation needed]. Whether the universe is “flat″ could determine its ultimate fate; whether it will expand forever, or ultimately collapse back into itself.