Epikurosz#132
"The known star with the greatest possibility of perturbing the Oort cloud in the next 10 million years is Gliese 710.[17] However, physicist Richard A. Muller and others have postulated that the Sun has a heretofore undetected companion (brown dwarf or gaseous giant planet) in an elliptical orbit beyond the Oort cloud. This object, known as Nemesis, is theorized to pass through a portion of the Oort cloud approximately every 26 million years, bombarding the inner solar system with comets. Although the theory has many proponents, no direct proof of the existence of Nemesis has been found.[18] Furthermore, many argue that a companion star at such a great distance could not have a stable orbit, as it would probably be ejected by perturbations from other stars."
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