London: A recent study had claimed that concentric rings within the cosmic microwave background could provide evidence of black holes that collided in the past, before our Universe existed but three new independent studies have challenged that claim.
Vahe Gurzadyan of Yerevan Physics Institute in Armenia theoretical physicist Roger Penrose of the University of Oxford, UK, had proposed that concentric rings of uniform temperature within the cosmic microwave background — the radiation left over from the Big Bang — might, in fact, be the signatures of black holes colliding in a previous cosmic ``aeon`` that existed before our Universe, reports Nature.
After analysing seven years` worth of data from NASA`s Wilkinson Microwave Anisotropy Probe (WMAP) satellite and calculating the change in temperature variance within progressively larger rings around more than 10,000 points in the microwave sky, Gurzadyan identified a number of rings within the WMAP data that had a temperature variance that was markedly lower than that of the surrounding sky.
But now Ingunn Wehus and Hans Kristian Eriksen of the University of Oslo2; Adam Moss, Douglas Scott and James Zibin of the University of British Columbia3 in Vancouver, Canada; and Amir Hajian of the Canadian Institute for Theoretical Astrophysics in Toronto, Ontario4 have challenged this idea.
The teams reproduced Gurzadyan`s analysis of the WMAP data and all agree that the data do contain low-variance circles.
They point out that the WMAP data clearly show that there are far hotter and cold spots at smaller angular scales, and that it is therefore wrong to assume that the microwave sky is isotropic.
They searched for circular variance patterns in simulations of the cosmic microwave background that assume the basic properties of the inflationary Universe, and all found circles that are very similar to the ones in the WMAP data.
Moss and his colleagues even found that both the observational data and the inflationary simulations also contain concentric regions of low variance in the shape of equilateral triangles.
"The result obtained by Gurzadyan and Penrose does not in any way provide evidence for Penrose`s cyclical model of the Universe over standard inflation," says Zibin.
Gurzadyan dismissed their analyses as "absolutely trivial", arguing that there is bound to be agreement between the standard cosmological model and the WMAP data "at some confidence level" but that a different model, such as Penrose`s, might fit the data "even better".
However, he is not prepared to state that the circles constitute evidence of Penrose`s model.
"We have found some signatures that carry properties predicted by the model," he says.