> We conclude that the maximum probability that panspermia sparked life on Earth is on the order of magnitude of 10-5, or 0.001 percent. Although this probabili

> We conclude that the maximum probability that panspermia sparked life on Earth is on the order of magnitude of 10-5, or 0.001 percent. Although this probability appears low, under the most optimistic conditions, potentially 4×109 total habitable zone exoplanets exist in our Galaxy, which could indicate a total of 104 habitable worlds harboring life.