The Sun goes up to 60 percent of its journey of 220 million years around the Milky Way
The major mass extinctions of species on Earth occurred during passage of the Solar System through the spiral arms of the Milky Way, according to a study published in Australia.
The research, led by Jonti Horner, University of New South Wales, determined the position of the sun during the different periods of extinction and found that most of them agreed with the passage of the solar system from galactic arms.
"We are not saying that every mass extinction is caused by the translational motion of the spiral arm", said Horner, who noted other factors that contributed to the extinction of species such as glaciations or flood basalts, but "it is a tantalizing sign".
The Sun goes up to 60 percent of its journey of 220 million years around the Milky Way's spiral arms, said Horner, co-author of the study that seeks to strengthen the hypothesis that the mass extinctions on Earth have not been accidental.
The six major extinctions occurred during the Late Cambrian, about 488 million years
The spiral arms of the galaxy are regions that have a higher density than average and where there is a greater presence of stars, molecular gas and dust clouds.
"Increasing the number of stars that the Sun is in its movement through the galactic arm could cause disruptions in gravity, sending comets Oort cloud toward the center of the solar system where the Earth", said Horner.
The Oort cloud, which lies on the edge of the solar system, is a reservoir of comets whose hypothetical collisions with Earth are one of the possible causes of mass extinctions by major volcanic eruptions of magma and avalanches of periods of glaciation.
Horner said that currently there have been only 182 craters caused by the impact of comets and asteroids, although most of the traces of these meetings have been erased by weather and geological phenomena.
Research suggests that while the flood basalts and glaciations occur sporadically and randomly, mass extinctions may respond to a specific pattern.
According to research, the disappearance coincides with the passage of the solar system from galactic arms
"Coordination of the time will never be perfectly accurate, but when looking at the data, the question remains always that extinctions are not completely randomly distributed over time, but were vaguely periodic", said Horner.
The six major extinctions occurred during the Late Cambrian, about 488 million years, the Late Ordovician (455), the Devonian (375), the Permian-Triassic (251), the Triassic-Jurassic (200) and the Cretaceous-Tertiary (66).
Recent cases have also been identified in species extinctions for 415, 322, 300, 145 and 33 million years.
"If we imagine for a moment that the only cause of extinction is related to the impact of comets, then it is more likely to have a collision when it passes through the galactic arm and sends density increase comets towards Earth", said Horner.