We may have got it all wrong about the shape of the Universe
We all know the Universe, right? Big thing, full of stars and planets, constantly expanding on a sort of flat plane. Well, it turns out we may not know it half as well as we thought.
The traditional model of the Universe sees it as ‘flat’. This is an image based on and borne out by, repeated observation and measurements from numerous different sources, but new evidence suggests that the picture astrophysicists have extrapolated from this data is misleading.
In fact, according to readings from the European Space Agency’s Planck telescope, the Universe may not be a ‘flat’ shape, where lines extend out in ever-expanding ways into infinity. Instead, it may be a ‘closed’ shape; a sphere-like our own planet, where lines curve back around on themselves.
This change of thinking could be a disruption in our understanding of the cosmos that is so shattering, it will require a total redraw and the contemplation of some funky new physics to explain what we’re seeing. Or it may be an anomaly, a fluctuation in an otherwise consistent picture.
Our image of a flat plane Universe has been built up from many different observations across many different observatories but the datasets gained over time from these myriad institutions have been collated and compiled, based on a particular sense of how they should fit together when, in reality, these data are not actually measured in the same consistent way, or even from the same cosmological model. Therefore, the conceptual framework we try to fit them into or measure them against really matters.
The differences they have presented from one another have traditionally been flattened out (see what I did there…?) into the flat Universe model, with attempts made to excuse, explain away or ignore some of the more troubling inconsistencies. However, the new Planck data suggests such inconsistencies may, in fact, make perfect sense, providing you allow for a closed shape to the cosmos.
The key discovery of the Planck telescope was an “enhanced lensing amplitude in cosmic microwave background power spectra”. This, in layman’s terms, means that the CMB (or Cosmic Microwave Background), the background radiation left over from the Big Bang (very faint and cold trace energy that can be found absolutely everywhere in the Universe) can be seen to bend more than it should, or at least more than can be accounted for by the objects that lie between us and it.
Einstein predicted and proved the concept of gravitational lensing, the idea that space itself is curved by the gravity, or mass, of the objects in it. This is a phenomenon that can be observed by the displacement of distant stellar objects, whose light has been curved in its path by intervening massive objects.
However, the idea that the Universe itself is a curved sphere, closing in on itself at the edges, is new, exciting, and as hotly contested as it is totally unproven. The anomalous bending could be a mere fluctuation, or it could be something unseen, but the team from the ESA is confident that the bending is consistent with a closed model of the Universe and this may be the best explanation for what they have found.
The ESA has already used previous Planck experiments to examine the CMB (discovering, in the process, that the Universe was slightly older than had been thought), but the cosmological crisis they may have unveiled is next-level stuff.
That said, there are a lot of things going against the closed Universe model. For one thing, all the previous analysis of Planck data has been consistent with the flat Universe model. For another, that famously tricksy Hubble Constant only gets harder to predict if you place it in a closed Universe model, and both cosmic shear data and the baryon acoustic oscillation surveys of dark energy are inconsistent with a closed Universe model.
So do we need to rethink space as we know it? Only time and a lot more data will tell.
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