A team of British scientists has just conducted a series of stringent tests, confirming the long-held assumption that the universe has no direction. According to them, the universe is not moving in any particular direction and is actually quite uniform, despite appearing clustered at smaller scales.
Our basic knowledge says that planets revolve around stars to form solar systems, with the stars in turn clumping together into galaxies. These galaxies join to give rise to massive galaxy clusters. The universe, as pointed out by the researchers, appears clumpy only locally. At larger scales, however, it is surprisingly uniform, irrespective of your position or the direction in which you are looking.
Most calculations in physics and astronomy are based on the assumption that the universe is directionless. As part of a new research, scientists from Imperial College London and University College London have confirmed this assumption using the most stringent test yet. According to the team, the study revealed only 1 out of 121,000 instances of the universe being clustered at certain points. Daniela Saadeh, a researcher at the University College of London and the paper’s lead author, said:
You can never rule it out completely, but we now calculate the odds that the universe prefers one direction over another at just 1 in 121,000. We’re very glad that our work vindicates what most cosmologists assume. For now, cosmology is safe.
For the project, the astronomers relied on maps of what is known as the cosmic microwave background (CMB) radiation. It is commonly regarded as the oldest light in the universe, produced right after the Big Bang. The maps, according to the team, were created using data collected by the European Space Agency’s Planck satellite between 2009 and 2013.
These maps are the first to provide a in-depth picture of the CMB’s intensity and polarization (or orientation) across the universe. The team listed a wide range of possible scenarios with different universes and their varying spins or directions, using the maps to determine which of them could generate the patterns of CMB. The findings of the new research was recently published in the Physical Review Letters journal.
As explained by the scientist, a universe that spins around an axis would likely create distinctly spiral patterns, while elongated cold and hot spots would occur in case of a universe that expands at varying speeds along multiple axes simultaneously. According to Stephen Feeney, a professor at Imperial College’s Department of Physics, none of the scenarios proved a conclusive match, in turn indicating that the universe is quite possibly directionless. Feeney said:
This work is important because it tests one of the fundamental assumptions on which almost all cosmological calculations are based: that the universe is the same in every direction. If this assumption is wrong, and our universe spins or stretches in one direction more than another, we’d have to rethink our basic picture of the universe… We have put this assumption to its most exacting examination yet, testing for a huge variety of spinning and stretching universes that have never been considered before. When we compare these predictions to the Planck satellite’s latest measurements, we find overwhelming evidence that the universe is the same in all directions
Source: Imperial College London