Muller's idea for Nemesis came to him 1983. Luis Alvarez, then an
emeritus professor of physics at the University of California at
Berkeley, and his son Walter had recently put forth the theory that a
giant impact had wiped out the dinosaurs. ... Luis Alvarez was Richard
Muller's mentor, and he suggested that Muller try to debunk the
periodicity argument. Pondering this, Muller dreamed up the fanciful
companion to the Sun as a possible cause, ... In the end, the idea
looked surprisingly plausible to Muller and his colleagues, and the
results of their work were ultimately published in the journal Nature in
1984. ...
Nemesis, as Muller sees it, is a common red dwarf star that would be
visible through binoculars or a small telescope, if only we knew which
of some 3,000 stars to look at. These are stars that have been
cataloged, but their distances are not known. ... Red dwarfs are the
most common stars in the galaxy. They are small and relatively cool,
dimmer than our Sun. The notion of companion stars is also exceedingly
common - more than half of all stars are part of such a binary system,
in which two stars are thought to form out of a single cloud of gas and
dust. ...
Others have suggested a dim failed star known as a brown dwarf might be
lurking in the distant fringes of the solar system. Muller called the
increasing rate of discovery of brown dwarfs, including one that is just
13 light-years away, "extremely discouraging." For if Nemesis were a
brown dwarf, it would be harder to find.Yet another enduring idea is
that another large planet lurks beyond Pluto. This so-called Planet X
would be a gas ball up to five times the size of Earth, according to
some predictions. ...
