Cosmology

Supernova in the galaxy M82 captured by the Swift satellite. Mid-ultraviolet light is shown in blue, near-UV light in green and visible light in red (Image NASA/Swift/P. Brown, TAMU)

A research conducted by a team led by astronomer Peter A. Milne of the University of Arizona published in two articles in the “Astrophysical Journal” shows that Type Ia supernovae can be divided into two groups with different characteristics. For years, astronomers had thought that their brightness depended almost exclusively on their distance. This can have consequences on our knowledge of the universe expansion, also calculated based on this type of supernovae.

Map of the polarisation of the Cosmic Microwave Background Radiation (Image ESA and the Planck Collaboration)

Nearly two years after presenting the best map ever made of the cosmic microwave background radiation, ESA revealed another map created using data collected by the Planck Surveyor space probe between 2009 and 2013. This new map shows the polarization of the cosmic microwave background radiation dating back to the early stages of the universe. It shows that the first stars started forming about 550 million years after the Big Bang, 100 million years later than previously thought.

Planck view of BICEP2 field (Image ESA/Planck Collaboration. Acknowledgment: M.-A. Miville-Deschênes, CNRS – Institut d’Astrophysique Spatiale, Université Paris-XI, Orsay, France)

In March 2014, the announcement that the BICEP2 (Background Imaging of Cosmic Extragalactic Polarization) experiment had detected gravitational waves in the perturbations in the cosmic microwave background radiation existing in the universe was sensational. This echo of cosmic inflation occurred shortly after the Big Bang was an extraordinary discovery. Unfortunately, a collaboration between the BICEP2 experiment and the team of ESA’s Planck space telescope has determined that those weren’t gravitational waves but probably emissions caused by galactic dust.