How is this that the Sun has a twin, and above, ‘bad’? It is a hypothesis developed in the 1980s about the nature of our own Solar System.
Surely you have studied in school that our Solar System is a system with a single star, at its center, around which the rest of the planets and objects orbit; the Sun itself also orbits around the center of the Milky Way, and is also moving. But what if I told you that the Sun is part of a binary star system?
In the 1980s, it was raised that perhaps the Sun was not alone, but had a partner. This hypothetical object was named “Nemesis”, after the Greek goddess of vengeance; and it was so named because it would be the apparent person responsible for the successive mass extinctions that the Earth has gone through, which, apparently, would take place in cyclical periods, every 27 million years.
It was Richard Muller, from the University of California Berkley, who proposed in 1984 that a red dwarf star, located one and a half light years from Earth, would be responsible for causing these mass extinctions. And how could a distant star do it?
Well, affecting with its gravity the Oort cloud, which is made up of icy rocks, far beyond Pluto, at the limits of the Solar System. Apparently, its elliptical orbit would have a frequency of 27 million years, and each time it travels through the Oort cloud, its gravitational influence would send comets towards the inner Solar System, causing an unusual bombardment, with the consequent cataclysm. .
According to Muller, Nemesis would have a size, somewhat larger than Jupiter, and both this hypothetical star, a supposed red dwarf, and the giant gas planets, are almost indistinguishable when it comes to being detected , and it is also just as difficult to detect them.
A similar hypothesis to this would be that of planet X, a massive planet still unknown beyond Pluto. Researchers Konstantin Batygin and Mike Brown suggested in 2016 that supposed planet X could be causing smaller icy bodies in the Kuiper Belt, a debris disk found within the Solar System.
But what credibility do these hypotheses have?
The Wide Field Infrared Reconnaissance Explorer (WISE) has never found any evidence of Nemesis, nor of the supposed planet X.
This recent study, which included an examination of WISE data covering the entire sky with infrared light, found no objects the size of Saturn or larger at a distance of 10,000 astronomical units (au); that is, no object is as large as ten thousand times the distance from the Earth to the Sun. To give you an idea, Pluto is from the Sun about 40 times this distance.
In addition, astronomers have explored the sky through the Two-Micrometer Whole-Sky Survey (2MASS on-screen ) project, which studied the sky for four years at three infrared wavelengths. The instrument discovered 173 brown dwarfs farther away than our solar system, but none close enough to be Nemesis.
NASA’s Wide Field Infrared Survey Explorer completed its 2011 mission, also discovered several brown dwarfs 20 light-years away; not close enough to be a candidate for Nemesis.
Besides there being no scientific evidence for the existence of Nemesis, or planet X, there is the issue of mass extinctions. Most scientists consider the cyclical theory of extinctions to be disproved, and others still give it some credence. Is it possible that all the extinctions were caused by an object from the frontier of the Solar System?
90% of the species that have ever inhabited the Earth are extinct . And the reason is that the Earth, in its four thousand five hundred million years of history, has suffered several extinctions, but we are going to review the five most important.
The First Great Extinction occurred 443 million years ago. And among the causes were considered from a glacial period, the decrease in the amount of oxygen, or the effects of the outbreak of a supernova. 86% of the species disappeared.
The second great extinction took place 367 million years ago.
During the Devonian-Carboniferous mass extinction, 82% of the species disappeared, including the famous trilobites.
Marine fauna was condemned to disappearance by a process that was occurring on the continents: the appearance of new plants whose roots released nutrients to the ocean, causing the population of algae to proliferate, and ending these with oxygen from the seas.
250 million years ago, during the third mass extinction, or Permian-Triassic extinction, 96% of species disappeared within a million years. It was the greatest extinction our planet has ever suffered. The cause was extremely intense volcanic activity, which expelled lava and tons of greenhouse gases, causing massive climate change.
The fourth extinction was the Triassic-Jurassic.
210 million years ago, at the beginning of the Jurassic period, 76% of species disappeared over 1 million years, and scientists again blame climate change caused by extreme volcanic activity, which fractured the continent of Pangea.
And finally, the fifth great and most famous extinction was the Cretaceous, 65 million years ago, in which most large animal species disappeared, including dinosaurs. This time, it did appear to be caused by the fall of an asteroid about 11 kilometers in diameter.
Returning to the evil twin of the Sun and its alleged existence, there seems to be no solid evidence that the 1984 hypothesis is correct.
An argument for a probable, but past, existence of Nemesis
In 2017, a study suggested that almost all stars like the Sun are born with at least one partner. The astronomers did detailed studies of young stars in the Perseus molecular cloud and supported their work with modeling. But “Nemesis”, if it existed at that time, broke free from the sun early in its history and moved to the rest of the population of the Milky Way.
Researchers at the Smithsonian Astrophysical Observatory studied the Perseus molecular cloud, a large star-forming region about 600 light-years from Earth, and found that most of them were binary systems.
Finally, the study concludes that most newly born binary stars, about 60 percent, end up their separate ways. And, according to the study, this was likely the fate of Nemesis and the Sun.
If Nemesis existed, it probably did so a long time ago, breaking free from the Sun early in its history and moving to the rest of the population of the Milky Way.
And you, what do you think about the existence of Nemesis?
