Approximately 66 million years ago, a large-scale bolide impact in the Caribbean region precipitated a global biological collapse, resulting in the extinction of non-avian dinosaurs and approximately 50% of all terrestrial and marine species.

約 6,600 萬年前，加勒比海地區的一次大規模火流星撞擊導致了全球生物崩潰，造成非鳥類恐龍以及約 50% 的陸地與海洋物種滅絕。

The event commenced with the descent of a rocky asteroid, estimated at 10 kilometers in diameter, which struck the ocean. The immediate kinetic energy transfer generated a transient cavity 30 kilometers deep and a rim exceeding 20 kilometers in height. This process released incandescent vapor exceeding 10,000 K, causing instantaneous incineration within the immediate vicinity. Subsequent thermal radiation and supersonic winds extended the lethal zone to a radius of 2,000 kilometers, while megatsunamis reaching 100 meters in height devastated coastal regions of the Gulf of Mexico and beyond.

此次事件始於一顆直徑估計為 10 公里的岩石小行星墜落並撞擊海洋。即時的動能傳遞產生了一個深 30 公里的暫時性腔體，以及一個高度超過 20 公里的邊緣。此過程釋放了超過 10,000 K 的熾熱蒸汽，導致周邊地區立即被焚毀。隨後的熱輻射與超音速風將致命區域擴大至 2,000 公里半徑，而高達 100 公尺的超級海嘯摧毀了墨西哥灣及其以外的沿海地區。

Following the initial impact, atmospheric perturbations became systemic. The ejection of sulfur-rich sediments and the synthesis of nitrogen oxides led to the precipitation of acid rain with pH levels as low as 1. Simultaneously, a global stratum of dust and soot obstructed solar radiation, reducing solar flux to one-thousandth of its baseline within one week. This induced a rapid thermal decline, with average surface temperatures decreasing by 15°C over the subsequent year. The resulting cessation of photosynthesis caused a collapse of primary productivity, leading to the starvation of apex predators and large reptiles.

在初步撞擊後，大氣擾動變得系統化。富硫沉積物的噴出與氮氧化物的合成導致了 pH 值低至 1 的酸雨降水。同時，全球性的塵埃與煙灰層阻擋了太陽輻射，在一個週內將太陽輻射通量降低至基線的千分之一。這導致了劇烈的溫度下降，隨後一年地表平均溫度下降了 15°C。隨之而來的光合作用停止導致初級生產力崩潰，導致頂級掠食者與大型爬行動物因飢餓而死亡。

Scientific validation of this hypothesis was established through the identification of an iridium anomaly in the K-Pg boundary layer, as reported by Luis Alvarez and colleagues in 1980. The subsequent discovery of a crater in the Yucatán Peninsula in 1991 provided the necessary geophysical evidence to corroborate the impact theory. The selective survival of small mammals, crocodilians, and certain avian species facilitated a biological rapprochement, wherein these organisms occupied the ecological niches vacated by extinct taxa, ultimately enabling the diversification of mammals.

該假設的科學驗證是透過 Luis Alvarez 及其同事於 1980 年報告的 K-Pg 邊界層中的銥異常而確立。隨後於 1991 年在猶加敦半島發現的隕石坑，提供了證實撞擊理論所需的地球物理證據。小型哺乳類、鱷魚類及某些鳥類物種的選擇性生存促進了生物的重新適應，這些生物佔據了滅絕分類群留下的生態棲位，最終實現了哺乳類動物的多樣化。

The Cretaceous-Paleogene event demonstrates the capacity of a single extraterrestrial impact to fundamentally restructure global biodiversity and climate.

白堊紀-古近紀事件證明了單次地外撞擊具有從根本上重構全球生物多樣性與氣候的能力。