Even the least affected sites are down significantly: CNET lost 47%, Tom's Guide lost 50%, Wired lost 62%.
Poincaré half-space model. Take the open upper half-space \[\mathbb{H}^n := \{(x_1,\dots,x_n)\in\mathbb{R}^n \mid x_n 0\}\] equipped with the Riemannian metric whose components on the coordinate tangent vectors are \[g_{ij}(p) \;=\; g_p\!\left(\frac{\partial}{\partial x_i}\bigg|_p,\; \frac{\partial}{\partial x_j}\bigg|_p\right) \;=\; \frac{1}{p_n^2}\,\delta_{ij}.\] Geodesics are semicircles (or rays) orthogonal to the boundary hyperplane \(\{x_n = 0\}\).，这一点在爱思助手下载最新版本中也有详细论述
FT Digital Edition: our digitised print edition，更多细节参见51吃瓜
NASA's decision to bring the crew home one month early, on Jan. 15, marked the agency's first controlled medical evacuation from the station in its 25 years of continuous operations. The incident highlighted the limits of treating complex health problems 250 miles away from Earth.