The asteroid not only supplied the iridium, but its
white-hot rock fragments also started fires that engulfed
entire continents. The soot from these fires, combined with
asteroid and crustal particles that were propelled into the
atmosphere, blocked out the Sun’s energy. The lack of sunlight
halted photosynthesis and caused a decrease in global
temperatures. Much of the plant and animal life, including
the dinosaurs, could not adapt to the temperature change
and died.