Alternative headline: Here’s a bug report for cosmology
The universe may not be expanding at the same rate in all directions according to a study backed by the European Space Agency – a possibility that has left cosmologists asking themselves some serious questions.
The cosmological principle rests on the idea the universe is both homogeneous and isotropic. In other words, it looks pretty much the same from any point when viewed across large enough scales.
The cosmic microwave background radiation, for example, appears to be spread uniformly across space-time. And the spatial distribution of galaxies is believed to be statistically the same, too, over hundreds of millions of light years. It also means the expansion rate of the universe is the same regardless of whichever direction you’re looking at the sky.
However, a paper published on Wednesday in Astronomy & Astrophysics casts doubt on that widely accepted hypothesis. A team at the University of Bonn, Germany, and America’s Harvard–Smithsonian Center for Astrophysics, claim to have discovered hundreds of galaxy clusters that appear brighter when viewed in a particular direction.
“Together with colleagues from the University of Bonn and Harvard University, we looked at the behaviour of over 800 galaxy clusters in the present universe,” said Konstantinos Migkas, first author of the paper and an astrophysics PhD researcher at Bonn.
“If the isotropy hypothesis was correct, the properties of the clusters would be uniform across the sky. But we actually saw significant differences.”[…]
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