Something terrible happens on Earth every 27 million years
Researchers discover that this is precisely the rate at which large mass extinctions occur, which coincide with an abnormal influx of large asteroids and gigantic volcanic eruptions.
Something terrible and tremendously destructive happens on Earth approximately every 27 million years. In effect, a new analysis just published in the journal Historical Biology has just revealed that on our planet also the mass extinctions of terrestrial animals, such as amphibians, reptiles, mammals, and birds, follow the same cycle of mass extinctions previously reported. ocean life.
The study also reveals that these major extinctions coincide with major episodes of asteroid impacts and devastating volcanic eruptions. “It seems that the impacts of large bodies and the pulses of the internal activity of the Earth that generate the great basalt eruptions - explains Michael Rampino, a biologist at New York University and lead author of the study - march at the same rate of 27 million of years than extinctions. A rhythm that perhaps depends on our orbit around the center of the galaxy.
Goodbye to the dinosaurs
66 million years ago, more than 70 percent of all terrestrial and marine species, including dinosaurs, suddenly became extinct due to the consequences of a large 10 km asteroid hitting Earth. Later, paleontologists discovered that mass extinctions of marine life, in which up to 90 percent of species disappeared, were not random events, but seemed to follow a cycle of about 26 million years.
In their study, Rampino, and colleagues Ken Caldeira of the Carnegie Institution for Science and Yuhong Zhu of the New York University Center for Data Science examined the record of mass extinctions of land animals and found that they also coincide. , almost perfectly, with the extinction of ocean life.
But what could be the cause of these massive and repetitive episodes of mortality? The answer could lie in the fact that mass extinctions are not the only events that occur in cycles. In fact, the ages of the impact craters, created by comets and asteroids colliding with Earth, also indicate a regularity that also lines up with that of extinction cycles.
Many astrophysicists are of the opinion that, between every 26 and 30 million years, a shower of comets occurs in the Solar System, which would explain the rate of formation of impact craters and the subsequent cycles of mass extinctions. The Sun and its planets are known to traverse the crowded plane of the Milky Way on their way around the center of the galaxy approximately every 30 million years.
At such times, it is very possible that kite showers will occur, and that many of them will end up crashing against us. The succession of impacts during these periods would cause our planet to go through long periods of cold and darkness, caused by the dense clouds of dust raised by the collisions, which would darken the atmosphere for thousands of years, and would also cause massive forest fires, acid rain, and depletion of the ozone layer. More than enough ingredients to cause a great extinction of species.
For Rampino, "these new findings of sudden mass extinctions and coinciding on land and oceans in a common cycle of 26 to 27 million years, support the idea of periodic global catastrophic events as triggers of extinction." In fact, scientists already know that at least three of the massive species killings on land and sea occurred at the same time as the three largest asteroid impacts of the last 250 million years, each of them with sufficient capacity to cause a global disaster.
The researchers, however, were surprised to find another possible explanation, besides asteroids, for the mass extinctions: gigantic volcanic eruptions that cover large tracts of land with lava. The eight coincident mass extinctions on land and sea, in effect, also occurred at the same time as large basalt eruptions.
" The great global mass extinctions - Rampino concludes - were apparently caused by the largest cataclysmic impacts and by massive volcanism, perhaps sometimes by the two together."