The Van Allen radiation belts exist because the Earth's magnetic field traps the solar wind. I wonder of other planets in our solar system share such a feature. The only reason I am thinking about this is its impact in the likelihood of finding ETI on extra-solar planets. I recall that the findings from the Viking mission were disappointing in the sense that they determined that Mars is too bombarded by radiation for life. I wonder what has been discovered about Venus. I know because of other environmental issues there is no life there. But I wonder if it has this sort of radiation belt around it.