Yes, an asteroid could be an Extinction Linked Event (ELE)
Due to cinema and fictional literature, we quickly associate a Extinction Linked Event (ELE) with global cataclysms, either caused by elements of our own planet, such as supervolcanoes, or by elements from space, such as asteroids. Remember movies like “East Java” of 1969, which takes place in the krakatoa eruption, one of the most violent in recent history or “Deep Impact” of 1998, when a comet is in charge of producing the catastrophe.
But there are other events, less striking for the making of movies or books, that can also be considered an ELE, since on a much smaller scale they are also capable of causing the extinction of one or several species.
What can be the Events Linked to Extinction?
There are many situations that can cause something as dramatic as the loss of species within the Biodiversity of our planet. Some are typical of the Earth, such as “mutations” that cause the emergence of a new pathogen, which in turn causes an especially virulent epidemic or pandemic, to the point of ending up with some endemic species of the affected region.
The human being has caused and is causing an ELE at a planetary level, as it is an “invasive species” with its arrival in unexplored corners of the Earth and compete for living space with better weapons against existing species. One of the most representative examples was the extinction of the Dodo, a flightless bird from the island of Mauritius, in the Indian Ocean, which was unable to adapt to the arrival of European settlers and the new fauna they brought with them.
Also from our planet would be the climatic changes, due to global warming or glaciation, although they would be more gradual modifications than the previous ones, with the possibility of adaptation, but being almost global they would affect a greater number of species. In this type of ELE we could include the supervolcanoes, which could cause what is called a volcanic winter, with a reduction in global temperature caused by the presence of volcanic ash in the atmosphere that would block the passage of the Sun’s rays.
Meteoroids, comets and asteroids
Coming from outside the Earth we have the possible impact of some body in space. We know that the atmosphere of our planet protects us from the continuous rain of cosmic dust and meteoroids, which are the smallest bodies in the solar system, which do not exceed a maximum of 5 meters in diameter. When they enter the Earth’s atmosphere and disintegrate, they give rise to a light phenomenon popularly known as a “shooting star” and that If they reach the earth’s surface, they are called meteorites..
At a higher level of size are the comets, made up of dust, ice and rocks, with a larger size, but which is usually difficult to catalog because their orbits are usually very far from us and when they approach the Sun, forming their typical hair, measurement is complicated, although comments with a radius of up to 30 kilometers have been observed.
And finally we meet Asteroids, which are celestial bodies made up of rocks, dust, and metals, ranging in size from meteoroids to dwarf planets. Currently there are several hundred thousand counted, most of them located in the asteroid belt, an area between the orbits of the planets Mars and Jupiter, others beyond the orbit of Neptune and the rest crossing the orbits of the planets towards the inner Solar System. When one of these celestial bodies crosses our atmosphere, it produces a very bright light, much more than in the case of meteoroids, receiving the name of “fireball or fireball”, which if it were to impact would also be called a meteorite, which according to its size could cause considerable damage.
Hundreds of asteroids visit us!
And precisely one of these celestial bodies is the one that has visited us recently, it is the new asteroid baptized with the name of 2022 AC4 and that this Tuesday passed at a distance of “only” 92,750 km from the center of our planet, which within astronomical measurements we can consider to be very close. For example, let us remember that the distance from Earth to the Moon is about 384,000 km, so passed only 24% of that distance.
We shouldn’t be scared for now. in the first 13 days of this year we have already been visited by more than ten asteroids. During 2021 we had the visit of a total of 145 asteroids. The 2022 AC4, discovered just two days before its approach, is the largest asteroid, between 4 and 10 meters in diameter and the closest it has been to us so far this year. If we consider 2021 it would also be among the biggest and closest.
In any case, there are continuous surveillance teams of possible objects close to our planet, one of the most important is the NASA and belongs to Jet Propulsion Laboratory, receiving the name of Center for Near Earth Object Studies (CNEOS). Most of these asteroids have orbits that do not bring them very close to our planet, but a small fraction of them, the so-called potentially dangerous asteroids, require more attention, both because of their size, greater than 140 meters, and because of their possible orbital approach.