THE Solar System may contain an extra planet made of a mysterious dark
substance called mirror matter, say physicists. The mirror world may even have
caused several mass extinctions on Earth.
Astronomers first suggested in the mid-1980s that a massive planet or star,
dubbed Nemesis, might exist—but it has never been spotted. Now, Robert
Foot of the University of Melbourne, Australia, and Zurab Silagadze of the
Budker Institute of Nuclear Physics in Novosibirsk, Russia, suggest that Nemesis
has proved elusive because it’s made of mirror matter and so is invisible.
Mirror matter has been appearing in physicists’ hypotheses since…
