The Shape of the Universe May Be Curved Rather Than Flat

Everyone is trying to get in shape … or trying to get everyone else to accept the shape they’re already in. That group may now include the universe itself – which was always thought to be flat but may now be joining the ranks of the round and curvy. Some cosmologists are calling this a ‘crisis’. Really? Are they body-shaming the universe?

“The assumption of a flat Universe could therefore mask a cosmological crisis where disparate observed properties of the Universe appear to be mutually inconsistent.”

In a paper published this week in the journal Nature Astronomy and reviewed in Live Science, astronomer Eleonora Di Valentino of Manchester University describes how she and an international team of colleagues used cosmic microwave background (CMB) data from the European Space Agency’s Planck satellite to support their conclusion that the universe is not a flat sheet but gently curved – a design which, taken to its physical and logical conclusion, supports the idea that the universe is a closed loop in the shape of an inflating balloon that continues to expand in all directions. However, unlike normal balloons, this on BEGAN with a “bang.”

The cosmic microwave background is believed to be radiation or heat leftover from the Big Bang, dating back to a mere 400,000 years after the universe began about 13.8 billion years ago. It exists across the entire universe but can only be detected in the microwave section of the electromagnetic spectrum. The ESA’s Planck space observatory mapped the anisotropies of the cosmic microwave background at microwave and infra-red frequencies from 2009 to 2013. That data was released to the public in 2018 and it’s where di Valentino, Sapienza University of Rome cosmologist Alessandro Melchiorri and Johns Hopkins University cosmologist Joseph Silk drew their conclusions.

“The recent Planck Legacy 2018 release has confirmed the presence of an enhanced lensing amplitude in cosmic microwave background power spectra compared with that predicted in the standard Λ cold dark matter model, where Λ is the cosmological constant. A closed Universe can provide a physical explanation for this effect, with the Planck cosmic microwave background spectra now preferring a positive curvature at more than the 99% confidence level.”

In Live Science, Melchiorri explains in simple terms that this closed universe means two photons traveling in parallel will eventually meet – something that’s impossible in a flat sheet universe. The team found a “gravitational lensing" anomaly in the CMB – gravity seems to be bending the microwaves of the CMB more than existing physics and general relativity can explain. The team concluded that a closed, curved universe would explain this anomaly. However, the calculations in the report do not achieve the 5 sigma (a statistical measurement that means about 99.8% confidence that the result isn't due to random chance) level of confidence.

Even just being extremely close, it’s enough for the researchers to title their paper “Planck evidence for a closed Universe and a possible crisis for cosmology.” Why a crisis? All physics pertaining to the superfast expansion of the universe after the Big Bang is based on a flat universe. Get rid of that and physics has to start all over again. That’s a crisis for everyone, with the exception of physics teachers and the publishers of physics textbooks. Melchiorri doesn’t want to be blamed for that, so he gives himself an out:

"I don't want to say that I believe in a closed universe. I'm a little bit more neutral. I'd say, let's wait on the data and what the new data will say. What I believe is that there's a discrepancy now, that we have to be careful and try to find what is producing this discrepancy."

More data. That seems to be the solution to most problems these days.