Seven ( and a half ) reasons to believe in Mirror Matter : From neutrino puzzles to the inferred Dark matter in the Universe

Parity and time reversal are obvious and plausible candidates for fundamental symmetries of nature. Hypothesising that these symmetries exist implies the existence of a new form of matter, called mirror matter. The mirror matter theory (or exact parity model) makes four main predictions: 1) Dark matter in the form of mirror matter should exist in the Universe (i.e. mirror galaxies, stars, planets, meteoroids...), 2) Maximal ordinary neutrino-mirror neutrino oscillations if neutrinos have mass, 3) Orthopositronium should have a shorter effective lifetime than predicted by QED (in " vacuum " experiments) because of the effects of photon-mirror photon mixing and 4) Higgs production and decay rate should be 50% lower than in the standard model due to Higgs mirror-Higgs mixing (assuming that the seperation of the Higgs masses is larger than their decay widths). At the present time there is strong experimental/observational evidence supporting the first three of these predictions, while the fourth one is not tested yet because the Higgs boson, predicted in the standard model of particle physics, is yet to be found. This experimental/observational evidence is rich and varied ranging from the atmospheric and solar neutrino deficits, MACHO gravitational microlensing events, strange properties of extra-solar planets, the existence of " isolated " planets, orthopositronium lifetime anomaly, Tunguska and other strange " meteor " events including perhaps, the origin of the moon. The purpose of this article is to provide a not too technical review of these ideas along with some new results.