广义相对论由 Albert Einstein 在 1915 年提出，将时空曲率与宇宙内容连结。Einstein 倾向于一个永恒静态模型；但在 1916–1917 年，Willem de Sitter 显示即使是无物质、仅含宇宙学常数的时空，也有三种情况，依 Λ 的符号分别为正（de Sitter）、零（平直）与负（anti-de Sitter）。Λ>0 时空以指数方式膨胀并形成视界，任何讯息都无法跨越；Monica Pate 将其比喻为逆流中的游泳者。Λ<0 时则像带边界的盒子，讯号或抛物体可被拉回，呈现持续的向心重力。
文章将我们的宇宙放在这些理想模型之间：早期可能近似为 de Sitter，经历 inflation 后因物质与辐射暂时接近平直，随著密度下降又再次越来越接近 de Sitter；UC San Diego 的 Daniel Green 估计这种趋势可能持续极长时间。量子层面上，随机涨落使小区域内粒子位置或粒子数等基本量成为机率性而非确定值。若要更精细地探测，理论上必须使用更高能量，因此需要以公里级（原文为 miles-long）粒子对撞机来研究极小尺度。
In theoretical cosmology, physicists often reduce possibilities to three idealized cosmic evolutions: expanding, collapsing, and static. The article says expanding universes are hardest to understand, yet our universe is indeed expanding and accelerating under dark-energy push. In collapsing or static backgrounds, methods in quantum theory can remain mathematically consistent, but in an expanding background they cannot be straightforwardly applied, so microscopic descriptions become hard to reconcile with macroscopic intuition.
General relativity, introduced by Albert Einstein in 1915, links spacetime curvature to cosmic content. Einstein favored an eternal static model, but in 1916–1917 Willem de Sitter showed that even matter-free spacetime with only a cosmological constant has three cases: positive (de Sitter), zero (flat), and negative (anti-de Sitter), depending on the sign of Λ. With Λ>0, spacetime expands exponentially and creates horizons that no signal can cross, which Monica Pate compared to swimming against a too-strong current. With Λ<0, it behaves like a bounded box where signals or thrown objects are pulled back, producing persistent inward gravity.
The article places our universe between these ideals: likely de Sitter-like during inflation, then near-flat for a long interval due to matter and radiation, and then becoming increasingly de Sitter-like again as density drops; Daniel Green of the University of California, San Diego suggests this may persist for a very long time. On the quantum side, random fluctuations make basic quantities such as particle position or particle number in a small region inherently probabilistic rather than certain. Finer probing requires higher energies in principle, which is why very high-energy kilometer-scale (originally “miles-long”) colliders are used to study microscopic physics.