Why is the universe pointing in one direction?

While the faster-than-light neutrinos are grabbing all the physics-shattering attention, there’s another strange, unexplained anomaly that might be about to rewrite our understanding of the cosmos. It’s all because the universe isn’t as monotonous as it should be.

The cosmic microwave background, which is the radiation left over from the Big Bang, is not exactly evenly distributed, with certain parts of the sky featuring higher concentrations of radiation than others. That, in itself, doesn’t go against the cosmological principle, which states that at large scales the universe looks the same all over.

What does appear to contradict this long-held principle is that the CMB distribution doesn’t appear totally random – instead, it appears aligned in a pattern that points in one particular direction. The line marked out by this distribution has been rather dramatically nicknamed the “axis of evil” by cosmologists.

This talked about this a few months ago on io9, and since then the evidence has only grown more compelling that this is a real phenomenon and not just a fluke – though it’s still well short of being considered a bona fide discovery. So what’s going on? Writing in Scientific American, Michael Moyer lays out some of the more amazing explanations:

The universe’s first burst of expansion could have lasted a little longer than we thought, introducing a tilt to it that still persists today. Another possibility is that at large scales, the universe could be rolled up like a tube, curved in one direction and flat in the others, according to Glenn D. Starkman, a cosmologist at Case Western Reserve University. Alternatively, the so-called dark energy-the bewildering stuff accelerating the universe’s expansion-might act differently in different places.

We don’t know which of these, if any, is the right explanation, or indeed if there’s actually anything there to explain. But between this, the faster-than-light neutrinos, and the recent antimatter imbalance discovered at CERN, we could be on the brink of a trio of discoveries that start a revolution in our understanding of the cosmos.

Edited from Why is the universe pointing in one direction?.

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