The status of searches for possible variation in the constants of nature from astronomical observation of molecules is reviewed, focusing on the dimensionless constant representing the proton-electron mass ratio μ=mp/me$\mu =m_{p}/m_{e}$. The optical detection of H2 and CO molecules with large ground-based telescopes (as the ESO-VLT and the Keck telescopes), as well as the detection of H2 with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope is discussed in the context of varying constants, and in connection to different theoretical scenarios. Radio astronomy provides an alternative search strategy bearing the advantage that molecules as NH3 (ammonia) and CH3OH (methanol) can be used, which are much more sensitive to a varying μ$\mu $ than diatomic molecules. Current constraints are |Δμ/μ|<5×10−6$|\Delta \mu /\mu | < 5 \times 10^{-6}$ for redshift z=2.0–4.2$z=2.0\mbox{--}4.2$, corresponding to look-back times of 10–12.5 Gyrs, and |Δμ/μ|<1.5×10−7$|\Delta \mu / \mu | < 1.5 \times 10^{-7}$ for z=0.88$z=0.88$, corresponding to half the age of the Universe (both at 3σ$3\sigma $ statistical significance). Existing bottlenecks and prospects for future improvement with novel instrumentation are discussed.

中文翻译：

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从分子的天文观测中寻找变化的自然常数

回顾了从分子的天文观测中寻找自然常数可能变化的状态，重点是代表质子电子质量比的无量纲常数 μ=mp/me$\mu =m_{p}/m_{e} $. 使用大型地面望远镜（如 ESO-VLT 和凯克望远镜）对 H2 和 CO 分子的光学探测，以及使用哈勃太空望远镜上的宇宙起源光谱仪对 H2 的探测是在不同背景下讨论的。常数，并与不同的理论场景有关。射电天文学提供了一种替代搜索策略，其优点是可以使用 NH3（氨）和 CH3OH（甲醇）等分子，它们对变化的 μ$\mu $ 比双原子分子更敏感。当前约束为|Δμ/μ|<5×10−6$|\Delta \mu /\mu | < 5 \times 10^{-6}$ for redshift z=2.0–4.2$z=2.0\mbox{--}4.2$，对应回溯时间为10–12.5 Gyrs，|Δμ/μ|<1.5 ×10−7$|\Delta \mu / \mu | < 1.5 \times 10^{-7}$ for z=0.88$z=0.88$，对应宇宙年龄的一半（均在 3σ$3\sigma $ 统计显着性）。讨论了新仪器的现有瓶颈和未来改进的前景。