You could often come across articles that the evil Nemesis rushes from the depths of space to destroy all life on Earth. It sounds scary, but is there really a threat? And why was Nemesis called the evil twin of the sun?
To begin with, Nemesis is a theoretical dwarf star, which is considered to be a satellite of the Sun. The fact is that usually stars are born in pairs. For many years, scientists could not understand why the sun rotates alone. It was suggested that earlier there was a star-partner, with which something happened. Or this star still exists, just for some reason we cannot find it.
Comparative size of Nemesis and the Sun
Where did the evil twin come from? It all began in the 1980s, when researchers noticed cyclicality in the extinction of species on Earth. It seemed strange that every 27 million years there are mass extinctions. The cyclicality and length of time indicated some repetitive astronomical influence.
In 1984, physicist Richard Muller suggested that a red dwarf should be blamed for extinctions, one and a half light years away from us. In later theories, they added that Nemesis can also be a white or brown dwarf. And some believe that we are dealing with a low-mass star (only several times more massive than Jupiter). But what is the connection between Nemesis and mass extinctions? The hypothesis states that Nemesis in its orbital passage affects objects in the Oort Cloud, located outside of the orbit of Pluto. There is an assumption: if Nemesis every 27 million years moves closer to the Oort Cloud, then it can push the comets out of the sphere and direct them towards the Sun and the Earth. A large comet crashes into our planet, which leads to mass death.
Nemesis estimated orbit
In addition, a clear outer edge is observed in the Oort Cloud, which could be “cut off” by the orbit of Nemesis. As evidence, mention is also made of the dwarf planet Sedna, whose orbital path lasts almost 12,000 years! Perhaps the presence of a dim star made this object move to such a great distance from the Sun.
It is important to understand that nemesis exists only in hypotheses. Scientists are still arguing about whether extinction events on Earth are a cyclical process. Also, researchers believe that nemesis should be tied to the sun by gravity, but it does not have a significant impact on the planets of the solar system. It is incredibly difficult and such an orbit could hardly remain stable.
Artistic interpretation of Nemesis. You see a red dwarf, asteroids and the sun (bright central point). And why can't we find Nemesis? Our technologies allow you to peer at billions of light years, why not look around? The fact is that red dwarfs are difficult to detect due to their dullness, and the search for brown dwarfs is even more difficult. Near the Sun, there are 173 brown dwarfs, but they are all farther than Nemesis’s supposed distance.
There is also the idea that the Sun was formed in a single copy, and the system spent the rest of the material on the creation of giant planets. We know about the existence of four giants, but somewhere else there may be another large planet located outside the Oort Cloud, which resent its icy objects.
So, nemesis may not exist at all. Or this object is carefully hidden from scientists, preparing to deliver another blow to mortal life. In any case, in the near future no danger is foreseen, so news of the threat from the evil solar twin can be safely ignored.