Around 66 million years ago, an asteroid or comet at least 10 kilometers (6 miles) in diameter impacted a few miles from the present-day town of Chicxulub in Mexico (hence it is dubbed as the “Chicxulub impactor”), at around 64,000 kilometers per hour (40,000 mph). The impact has created a crater (Chicxulub crater) more than 180 km (110 miles) in diameter. But, what’s more, the energy of the impact (which is equivalent of about ten billion Hiroshima atom bombs) vaporized the rock which was rich in sulfur compounds, filling the air with a thick cloud of dust, similar to that created by a catastrophic volcanic eruption.
This cloud blocked out the sun at least for a decade and caused a global, dark winter: even in the tropics the temperatures were barely above freezing, and the average global temperature was below 0°C (32°F). Before the impact, the average global temperature was around 26°C (47°F), so this means a huge drop. And the recovery time was more than 30 years! The dinosaurs which had dominated the Earth for more than 150 million years were used to living in a lush climate and were already in decline, so non-avian dinosaurs couldn’t survive after the last deadly blow.
