Most scientists agree that the impact of an asteroid hitting Earth played a major role in the extinction of dinosaurs but now there's a brand new theory about how exactly that happened.
The only break much of America can hope for anytime soon from eye-watering dangerous smoke from fire-struck Canada is brief bouts of shirt-soaking sweltering heat and humidity from a southern heat wave that has already proven deadly, forecasters say.
Over 120 million Americans were under air quality alerts on Wednesday from the smoke of the Canadian wildfires and it will continue on Thursday. Meanwhile, the heat continues in the Southern states.