JHUAPL-Sandia Model Finds 20 Billion Earth Cells Potentially Delivered to Venus Clouds Over 1 Billion Years

The team combined the pancake fragmentation model with prior ejection and survival simulations to track how impact ejecta from Earth or Mars would ablate, burst, and disperse as sub-cloud particles. They fed these delivery rates into the 2021 Venus Life Equation framework, multiplying origination, robustness, and continuity terms to bound the probability of extant atmospheric life. Their preferred run yielded 20 billion cumulative cells over the past billion years, with viability windows of days per century inside the habitable cloud deck.

This calculation extends earlier lithopanspermia studies focused on Mars-Earth exchanges by quantifying the higher entry velocities and denser Venus atmosphere that produce more numerous but smaller surviving fragments. It also highlights how the continuity factor in the VLE remains the dominant uncertainty, because even modest desiccation or acidity spikes could erase any delivered population before replication occurs.

Future in-situ measurements from the DAVINCI or VERITAS missions could directly test the prediction by searching for isotopic or genomic signatures inconsistent with indigenous Venusian chemistry. If no such anomalies appear after sampling 10^6 cloud particles, the effective transfer survival fraction would need downward revision by at least two orders of magnitude.