TLDR: An asteroid doesn't seem to be the cause of the dinosaurs going extinct. The asteroid defintely occurred, yet it seems like the Jurassic extinction was years afterwards while the nuclear winter seems to only have taken place briefly. By focusing on mean temperature and bacterial cell morphology post the asteroid, our current understanding would impact everything from dino's to microbes yet microbes we're thriving years after the impact. Current idea's are revolving around a volcano in India being the cause of extinction, but more research is needed to confirm.