The Cosmic Coincidence Problem and Its Common-Origin Solution: On the Present-Day Proximity of Dark Energy and Dark Matter

The cosmic coincidence problem is one of the most unsettling questions of standard cosmology: while the dark-energy density stays constant, the matter density dilutes as a⁻³. These two quantities, seemingly entirely independent of each other, become comparable only within a brief window of cosmic history — and we sit exactly in that window. This review offers a common-origin solution to the problem from a planckon-based discrete framework and builds the framework self-containedly: the mathematical point is excluded from ontology (the rejection of zero); the planckon is the finite physical realization of the point; space is the folding cubic bond lattice of the nodes; time is not a dimensional axis but the measurement record of the occurrence of events (τ = n·tP). The energypotential ledger E(d) = (d+1)εP, U(d) = (3−d)εP is derived from the direction count of this geometry; the budget items are states of a single ledger — dark energy is the closed reserve of nodes that have not yet formed a bond (the d0 pool); dark matter is the chain remnant frozen after forming its first bond but failing to complete the climb (d1); visible matter is the fraction that finishes the closure and locks in (d3). The solution has four layers. Common origin: the two dark densities are not two independent substances but two fates of a single reservoir — there are no two free constants whose coincidence must be arranged. Common threshold: pairing and climbing are events of the same kind (bond formation) and are subject to the same freeze threshold; a single cooling event releases both dark remnants at once. Quantitative skeleton: the per-node energies are exact from the ledger (pool 3εP, frozen chain exactly one εP per node); the observed 68.3/26.8 ratio reduces to the proximity f_d0/f_d1 ≈ 0.85 of two sibling populations. Magnitude proof: the time principle closes the magnitude component of the “why now” question — in every power-law era λ·n = H·t = O(1) is an identity, and the dark-energy density reduces to the clock-squared law: ρ_DE/ρP = (3Ω_DE/8π)·λ² ≈ 10⁻¹²³; the order 10⁻¹²² is not a tuned constant but the current reading of the event counter (n ≈ 8.1×10⁶⁰). The distribution component, in turn, finds its form through the exact solution of the folding kinetics: the population fractions follow the three-axis binomial law (f_d = C(3,d)·a³⁻ᵈ(1−a)ᵈ), the sibling-population ratio reduces to a single parameter, and the stopping scale is derived within the framework by the full integration of the ledger set (A_f/A_c = 1.45–1.46; Proposition 8; closed form log₂(11/4) = 1.4594 — the counting closure of the unified-cycle paper), yielding f_d0/f_d1 = 0.8617 — within 1.4% of the observed 0.85. The derivation is free of budget circularity: the composite budget→stopping→budget map is a contraction (|dr′/dr| ≈ 0.03) and converges to the attractor r* = 0.877 from any initial 1 partition; the observation is also within 3.2% of the attractor. The framework’s distinguishing prediction is recorded: the equation of state cannot be w = −1; a draining pool carries a w signature that deviates from −1, is strictly decreasing, and evolves in time.