Time required for the reflectance of solid ethane at wavelengths shorter than 400 nm to decrease by 50% (τ₅₀) as a function of temperature. Circular symbols represent experimental measurements between 57.5 K and 62 K at selected wavelengths in the reflectance spectra. The shaded region indicates the range of reddening timescales – bounded by the maximum and minimum values derived from Arrhenius fits across all measured wavelengths. The strong temperature dependence implies that reddening becomes progressively slower at lower temperatures, extending to century-long timescales near 45 K.