In the proposed light-dark dual universe, the light universe is the observable universe with light and kinetic energy that fueled the Big Bang, and the dark universe without light and kinetic energy has been observed as dark energy since about 9 billion years after the Big Bang. The light-dark dual universe started from the zero-energy universe through the four-stage cyclic transformation. Emerging from the zero-energy universe, the four-stage transformation consists of the 11D (dimensional) positive-negative energy dual membrane universe, the 10D positive-negative energy dual string universe, the 10D positive-negative energy dual particle universe, and the 4D (light)-variable D (dark) positive-negative energy dual particle asymmetrical universe. The transformation can then be reversed back to the zero-energy universe through the reverse four-stage transformation. The light universe is an observable four-dimensional universe started with the inflation and the Big Bang, and the dark universe is a variable dimensional universe from 10D to 4D. The dark universe could be observed as dark energy only when the dark universe turned into a four-dimensional universe. The four-stage transformation explains the four force fields in our universe. The theoretical calculated percentages of dark energy, dark matter, and baryonic matter are 72.8. 22.7, and 4.53, respectively, in nearly complete agreement with observed 72.8, 22.7, and 4.56, respectively. According to the calculation, dark energy started in 4.47 billion years ago in agreement with the observed 4.71 ± 0.98 billion years ago. The zero-energy cyclic universe is based on the space-object structures.

The paper posits that the multiverse is reversible, so all universes in the multiverse are reversible cyclic universes which have the inexhaustible resources of space-time to expand. The collision of expanding universes is permanently irreversible, forbidden in the reversible multiverse, so every universe is surrounded by the zero-energy interuniversal void as the permanent gap among universes to keep universes apart. A zero-sum energy dual universe of positive energy universe and negative energy universe can be created in the interuniversal void, and the new dual universe is again surrounded by the interuniversal void. This paper also posits the reversible string theory with oscillating space-time dimension number oscillating between 11D (space-time dimension) and 4D without the conventional compactization of string. Dimension number decreases with decreasing speed of light, decreasing vacuum energy, and increasing rest mass. The 4D and the 11D have zero and the highest vacuum energies, respectively. The universes in the reversible multiverse oscillate reversibly between high and low dimension numbers. Under symmetry breaking as in our universe, the positive energy universe as our observed universe absorbed the interuniversal void, while the negative energy universe did not. The interuniversal void has zero vacuum energy, so the absorption of the interuniversal void by the positive energy universe forced the positive energy 10D universe with high vacuum energy to be transformed into the positive energy 4D universe with zero vacuum energy, resulting in the inflation followed by the Big Bang. The negative energy universe undergoes dimension number oscillation between 4D and 10D dimension by dimension. The negative energy >4D universe is hidden, and the negative energy 4D universe appears as dark energy. The calculated percentages of dark energy, dark matter, and baryonic matter and the calculated time for dark energy to start are in good agreements with the observed values.

The proposed universal psychological mechanism for developmental psy-

The paper posits that kin sociality and eusociality are derived from the handicap-care principles based on the need-based care to the handicappers from the caregivers for the self-interest of the caregivers. In this paper, handicap is defined as the difficulty to survive and reproduce independently. Kin sociality is derived from the childhood handicap-care principle where the children are the handicapped children who receive the care from the kin caregivers in the inclusive kin group to survive. The caregiver gives care for its self-interest to reproduce its gene. The individual's gene of kin sociality contains the handicapped childhood and the caregiving adulthood. Eusociality is derived from the adulthood handicap-care principle where responsible adults are the handicapped adults who give care and receive care at the same time in the interdependent eusocial group to survive and reproduce its gene. Queen bees reproduce, but must receive care from worker bees that work but must rely on queen bees to reproduce. A caregiver gives care for its self-interest to survive and reproduce its gene. The individual's gene of eusociality contains the handicapped childhood-adulthood and the caregiving adulthood. The chronological sequence of the sociality evolution is individual sociality without handicap, kin sociality with handicapped childhood, and eusociality with handicapped adulthood. Eusociality in humans is derived from bipedalism and the mixed habitat. The chronological sequence of the eusocial human evolution is 1) the eusocial early hominins with bipedalism and the mixed habitat, 2) the eusocial early Homo species with bipedalism, the larger brain, and the open habitat, 3) the eusocial late Homo species with bipedalism, the largest brain, and the unstable habitat, and 4) extended eusocial Homo sapiens with bipedalism, the shrinking brain, omnipresent imagination, and the harsh habitat. The omnipresence of imagination in human culture converts eusociality into extended eusociality with both perception and omnipresent imagination.

All leptons, quarks, and gauge bosons can be placed in the periodic table of elementary particles. As the periodic table of elements derived from atomic orbital, the periodic table of elementary particles is derived from the two sets of seven orbitals: principal dimensional orbital and auxiliary dimensional orbital. (Seven orbitals come indirectly from the seven extra dimensions in eleven-dimensional space-time.) Principal dimensional orbital derived from varying space-time dimension, varying speed of light, and varying supersymmetry explains gauge bosons and low-mass leptons. Auxiliary dimensional orbital derived from principal dimensional orbital accounts for high-mass leptons and individual quarks. For hadrons as the composites of individual quarks, hadronic dimensional orbital derived from auxiliary dimensional orbital is responsible. These three sets of seven orbitals explain all elementary particles and hadrons. QCD, essentially, describes the different occupations of quarks in the three sets of seven orbitals at different temperatures. The periodic table of elementary particles and the compositions of hadrons relate to the Barut lepton mass formula, the Polazzi mass formula for stable hadrons, and the MacGregor-Akers constituent quark model. The calculated masses for elementary particles and hadrons are in good agreement with the observed masses. For examples, the calculated masses for the top quark, neutron, and pion are 176.5 GeV, 939.54MeV, and 135.01MeV in excellent agreement with the observed masses, 174.3 ± 5.1GeV, 939.57 MeV, and 134.98 MeV, respectively. 1.