The secret was there, trapped in the Antarctic ice, just waiting for researchers to brave the cold to flush it out: proof of the existence of a universe parallel to ours, where time would pass in reverse. This infinitely attractive story, worthy of the best science fiction scenarios, media from around the world have relayed it in recent days. Alas, the authors of the "discovery" are now showering hopes, considering this hypothesis to be the least adventurous ...
At the origin of this fable, there is a very serious project called Anita (for Antarctic Impulsive Transient Antenna), funded in part by NASA, the American space agency. On several occasions since 2006, a balloon clad with radio antennas has flown over Antarctica in search of particles coming from very far in space and which can provide information on the origin of cosmic rays.
Why over the white continent? Because to detect these very high-energy particles, researchers are interested in the radio waves emitted during their interactions on the surface of the Earth and only materials such as salt or ice are sufficiently transparent so that they can be perceive.
When we scrutinized their data, scientists found weird things. On very rare occasions, cosmic rays seemed not to be reflected in the ice but to emerge from the ice, as if they did not come from a place far from space but from the Earth itself. Consequently, the researchers of the Anita project tried to understand what appeared to be "anomalies" and published their first observations in 2016.
It was also from there that things began to "escape". The strange discovery has indeed tickled many other scientists. In May 2018, the team of Luis A. Anchordoqui, of New York University, postulated that the “events of Anita” would be “proof” of the existence of a “symmetrical universe”. His reasoning? The particles in question could not, according to them, "cross" the Earth, if they seem to emerge from it, it is because they go back ... in time, and therefore evolve in a parallel universe. The hypothesis was detailed in April 2020 in New Scientist, a renowned British journal.
And it was not always scrupulous that the information was taken up last Sunday by the British tabloid Daily Star, then in the days that followed by other titles with strong audiences on both sides of the Atlantic (New York Post, The Sun, Daily Mail ...), including in France.
Earth crossed by particles
Seeing her works misinterpreted, Peter Gorham, manager of Anita, made things clear. "This whole story of parallel universe was not invented by us, but in one way or another, we were associated with it," he lamented Thursday on the website of the University of Hawaii, where he teaches physics. “A journalist made a mistake, linked him to us and unfortunately snowballed. In fact, we had nothing to do with the development of the idea of a parallel universe. "
Quoted on Friday by the ScienceAlert site, Peter Gorham describes the approach adopted by his team: "We encountered a small number of anomalies in our data, and once we have exhausted all the possible explanations in the standard model of physics, it is only then that it is time to consider other ideas that push these limits - we are really not yet, certainly not, at the point where parallel universes are necessary! "
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Anita researchers favor the hypothesis that the particles detected did indeed come from space but passed through the Earth! Which is already fascinating!
The laws of physics challenged?
Astrophysicists know that certain particles, neutrinos, interact very little with matter. Those who come from the Sun are thus able to cross our planet. What surprises them is that it is the same with very high energy particles from far away. "At these incredible energy levels, neutrinos are like bulls in a china shop - they become much more likely to interact with particles from Earth," said Professor Alex Pizzuto of the University of Wisconsin - Madison, in a blog post last January.
In order for some of these particles to have passed through the planet, they would therefore have to be "bombarded". For example, by an exploding star, supernova type, as the Anita team suggested. But this idea is not corroborated by the experiences of the IceCube observatory, which is also interested in neutrinos in Antarctica and for which Alex Pizzuto works. The two teams are in any case in agreement on one point: if the anomaly is not due to a detection problem, the explanation could defy the standard model of particle physics.
Questioned by Le Parisien, Fabian Schüssler, astrophysicist at the Atomic Energy Center (CEA), defends another hypothesis put forward in a scientific article last year: the shape of the ice layers could have had an impact on the detection of signals. He suggests going to probe the cap at the precise places where the anomalies occurred. Which would perhaps, finally, to solve the mystery.