Ellipsoidal universe

A new theoretical assessment of data taken by the Wilkinson Microwave Anisotropy Probe suggests that the observable universe is not spherically symmetric, but more like an ellipsoid. The WMAP data have helped nail down some cosmological parameters such as the age of the universe since the Big Bang (13.7 billion years), the time when the first atoms formed (380 000 years after the Big Bang), and the fractions of all available energy vested in the form of ordinary matter, dark matter, and dark energy (roughly 5%, 25%, and 70%, respectively). One remaining oddity about the WMAP results, however, involves the way in which different portions of the sky contribute to the overall map of cosmic microwaves: Samples of the sky smaller than tens of degrees across seem to be contributing radiation at expected levels; only the largest possible scale, on the order of the entire sky, seems to be underrepresented. That largest scale is measured in the radiation’s quadrupole moment. Now Leonardo Campanelli of the University of Ferrara and his colleagues Paolo Cea and Luigi Tedesco at the University of Bari (all in Italy) have taken a closer look at the so-called quadrupole anomaly. They found that if the surface of last scattering—the shell from which the cosmic microwaves come toward Earth—is slightly ellipsoidal rather than spherical, then the WMAP quadrupole is just what it should be. The cosmologists say that a nanogauss magnetic field pervading the cosmos could bring about the required 0.01 eccentricity. An ellipsoidal universe would nicely parallel Johannes Kepler’s discovery that the planetary orbits are ellipses and not circles. (L. Campanelli, P. Cea, L. Tedesco, Phys. Rev. Lett. 97 , 131302, 2006 http://dx.doi.org/10.1103/PhysRevLett.97.131302 .)