What do the fundamental constants of physics tell us about life?

TL;DR

The paper extends Weisskopf's program to living matter, showing that fundamental constants ($c$, $\hbar$, $e$, $m_e$, $m_p$, $G_N$) plus basic biophysical scales can quantitatively bound key properties of chemical self-replicators: growth yield $Y$, minimum doubling time $\tau_{double}$, and maintenance power $P_{min}$. It derives emergent scales from atomic physics, such as the Bohr radius $a_0$, Rydberg energy $Ry$, the chemical assembly constant $Y_c$, and the Berg viscosity $\nu_{B}$, and uses diffusion-limited kinetics and transition-state arguments to connect these to replication rates and energy costs. The results yield order-of-magnitude estimates in close agreement with terrestrial measurements (e.g., $Y \sim 1\times 10^{-4}$ g/J, $\tau_{double}$ spanning minutes to years, $P_{dorm}$ around $10^3$ ATP/s per cell), and predict relative invariance of yield versus variability of doubling time and maintenance power across life forms. These findings suggest that the laws of physics impose universal constraints on biology, potentially extending to life beyond Earth, and provide a physics-grounded framework to anticipate properties of hypothetical chemistries that could support self-replication.

Abstract

In the 1970s, the renowned physicist Victor Weisskopf famously developed a research program to qualitatively explain properties of matter in terms of the fundamental constants of physics. But there was one type of matter prominently missing from Weisskopf's analysis: life. Here, we develop Weisskopf-style arguments demonstrating how the fundamental constants of physics can be used to understand the properties of living systems. By combining biophysical arguments and dimensional analysis, we show that vital properties of chemical self-replicators, such as growth yield, minimum doubling time, and minimum power consumption in dormancy, can be quantitatively estimated using fundamental physical constants. The calculations highlight how the laws of physics constrain chemistry-based life on Earth, and if it exists, elsewhere in our universe.

Figures (2)

• Figure 1: Characterizing chemical self-replicators. (a) Self-replication requires organisms to break down food molecules from the environment to extract energy and metabolic precursors (catabolism) and then use this energy to synthesize the complex molecules necessary for self-replication (anabolism). (b) We focus on three properties of self-replication: (i) the mass per unit energy consumed needed to self-replicate, (ii) the time it takes for self-replication, and (iii) the energy per unit time a dormant cell must expend in order to stay alive and counter entropic forces.
• Figure 2: From fundamental constants to self-replicator properties. The fundamental physical constants give rise to emergent physical scales that govern the properties of chemical self-replicators.