It is impossible to calculate exactly, but computer models estimate that there are currently about 17,000 impacts annually. If we add up the weight of all this extraterrestrial material, we find that the planet receives annually about 40,000 tons of meteoric material. Luckily for us, the vast majority of it is very small – grains of dust – and we are rarely hit by a rock of a certain volume: the last considerable one exploded about 15 kilometers above the Ural Mountains (Russia) on 15 February 2013, and its shock wave caused around a thousand injuries. The object was about 17 meters wide and its mass was between 7,000 and 10,000 tons.
The apocalypse from space
Little compared to the meteorite that triggered the end of the dinosaurs 66 million years ago: between ten and twelve kilometers in diameter, its collision with what is now the Gulf of Mexico and the Yucatan Peninsula released an energy equivalent to the of 10 billion bombs like the one in Hiroshima, it generated a massive tsunami and sent huge amounts of sulfides and carbon dioxide into the atmosphere.
The energy, heat and speed of that rock at the end of the world caused an explosion difficult to imagine. The catastrophic sequence began with the enormous temperature that the meteorite acquired due to its friction with the atmosphere, more than 3000 ºC. With the impact, all that thermal and kinetic energy was transferred to the ground, which increased the temperature by a few hundred degrees Celsius. The shock wave from the shock traveled at high speed over the ground and through the air. The heat was such that the liquids boiled and the earth vaporized.
Fires on a scale never seen before erupted immediately, tsunamis and a huge cloud of gas, dust and sulfuric acid droplets that was estimated to have remained in the atmosphere for about three years and plunged Earth into a long, cold winter. With the blocking of the entry of solar radiation, the average annual air temperature dropped by at least 26 ºC. Without the sun to photosynthesize, the plants were the first to disappear, and the food chain was touched to death.
Not all life ended: the new reality allowed small mammals to progress and evolve, and millions of years later a naked ‘monkey’ simulated that catastrophe in its laboratory, aided by flour, cocoa and a heavy ball. Without causing any extinction, we got a good impact crater and a shock wave that raised a lot of white dust that took hours to clean.
