The giant asteroid impact 66 million years ago in the Yucatan region of Mexico, which led to the extinction of the dinosaurs, could have been very different. The location of the impact area contained major deposits of calcium sulphate.
The calcium sulphate in the crater area had been vaporized into the atmosphere and had become a dense sulphur dioxide veil stopping the sunlight. The explosion from the impact was the equivalent of 10 billion Hiroshima bombs. Worldwide climate disruption from the event was the cause of the Cretaceous–Paleogene extinction event, a mass extinction in which 75% of plant and animal species on Earth suddenly became extinct, including all non-avian dinosaurs.
Since the earth spins, if the impact would have been mere seconds later the asteroid would have impacted in the ocean. There would have been no sulphur dioxide veil! The dinosaurs would not have went extinct. If the dinosaurs would have survived, and subsequently thrived, would the dominant intelligent life form on the planet today be reptilians?