Since the age-old question - and one that most people now agree on - about the shape of the Earth has resurged, it seems people have also recently been reconsidering the shape of the Universe. But unlike our blue planet, which can be seen from space and therefore means we have concrete proof of its shape, it is more difficult to discern the architecture and design of something… when you are inside it! Years of observational data and cosmological models have suggested that the Universe was flat. But a more recent study that was published in Nature on November 4 of last year suggests this may not be true.
Observation of an anomaly
This new research is based on data that was obtained from the European Space Agency (ESA) Planck satellite last year. Astronomers at the University of Manchester have come to the conclusion that in reality, the Universe could actually be curved and closed like an inflated spherical balloon. In their flat model, when a beam of photons is shot through the vacuum, they would naturally continue in a straight line. But this new theory suggests that this beam might eventually end up back at its starting point.
To understand this phenomenon, researchers explained that the clue to the curvature of the Universe lies in the way that gravity plays with and bends the path of light. This is what Albert Einstein referred to as ‘gravitational lensing’. And not just any light, either, but the cosmic microwave background (CMB) - the electromagnetic radiation that exists between stars and galaxies. To put it simply, when all other light sources are blocked, space lets off a weak ‘glow’, which is the oldest light in the Universe and is due to the radiation that still exists in the Universe dating back 380,000 years after the Big Bang.
However, the Planck satellite has observed that this CMB is more strongly polarised by gravity than it should be. Researchers are calling this anomaly ‘A-lens’ and it is yet to be resolved, but the team believes that this explanation could be the shape of the universe.
Although researchers generally welcome new scientific discoveries, this particular revelation is thought to be bad news. According to them, their conclusions are synonymous with a 'cosmological crisis’ that calls for a ‘drastic rethinking of the current cosmological concordance model.' However, previous analyses of data obtained from the Planck satellite did suggest that the current cosmological models are correct, including the one stating the Universe is flat.
Another problem lies in the Hubble constant, which describes the speed at which the Universe is expanding. At the moment, there are no two measurements of this constant agree and if the Universe were actually curved, it would mean making predictions about our Universe would be much more difficult. Other data, such as that included in a study into dark energy - the unknown energy accelerating the expansion of the Universe, are also inconsistent with the closed Universe model.
But at the end of the day, with the exception of the anomalies observed by the Planck satellite, much of the current research seems to be consistent with the flat universe model instead of the curved, closed model. Another paper released by the University of Cornell (USA) suggests that the discrepancies between the objectives of the ESA satellite could constitute some kind of gap in the data.
According to the researchers:
Future measurements are needed to clarify whether the observed discordances are due to undetected systematics, or to new physics or simply are a statistical fluctuation.