The theory of the Sun's twin, often called "Nemesis," is a speculative astronomical hypothesis that suggests our Sun might have had—or still has—a companion star, possibly responsible for mass extinctions on Earth.
Origin of the Nemesis Theory
Proposed in 1984 by physicists Richard A. Muller, Marc Davis, and Piet Hut.
Based on the observation that mass extinction events (like the one that wiped out the dinosaurs ~66 million years ago) seemed to occur periodically—roughly every 26 million years.
Core Idea
The theory suggests that the Sun has a distant, dim companion star—possibly a red or brown dwarf—in a highly elliptical orbit.
Every ~26 million years, this companion (Nemesis) passes through the Oort Cloud, a region of icy bodies on the edge of the solar system.
This disturbance could send comets hurtling toward the inner solar system, increasing the chance of impact events on Earth.
Support and Skepticism
Support:
Initial support came from perceived patterns in extinction data.
Some indirect hints like unexplained long-period comets entering the inner solar system.
Skepticism:
No direct observation of such a companion star has ever been made.
Modern sky surveys like WISE (Wide-field Infrared Survey Explorer) have not detected any nearby dim stars in expected orbits.
Many scientists believe extinction patterns can be explained by geological or terrestrial causes (volcanism, climate change, etc.).
Current Status
As of now, Nemesis remains a hypothetical object.
Most scientists consider the theory unlikely due to a lack of observational evidence.
However, it played a significant role in sparking further research into mass extinctions and solar system dynamics.
