Things are "impossible" if they can never happen at all, or if the probability is astronomically against it. What are the odds that the guy sitting next to you on the bus has the same birthday? No less than 1 in 365. It happens. There is a whole area of engineering that treats with the occurrence of events. The design probability requirement that an airliner should complete a flight safely is one in 10 million. Not zero. If you want better than that, be prepared to pay for it.
Things are "impossible" if they can never happen at all, or if the probability is astronomically against it. What are the odds that the guy sitting next to you on the bus has the same birthday? No less than 1 in 365. It happens. There is a whole area of engineering that treats with the occurrence of events. The design probability requirement that an airliner should complete a flight safely is one in 10 million. Not zero. If you want better than that, be prepared to pay for it.