Washington (AFP)

"The first thing I know about my discipline is that its name, the Big Bang theory, is not fair," says American professor James Peebles, one of three Nobel Prize winners in 2019, in front of an intrigued audience.

"It connotes an event and a place, but both are wrong," he continues in front of science enthusiasts who came to hear at the House of Sweden, Washington, three American Nobel laureates - the symposium organized by the Embassy is annual, there are always Americans in the list.

No big original explosion, until proven otherwise.

James Peebles, 84, is a cosmologist. The Nobel rewarded his theoretical work on the childhood of the universe.

Note the nuance: childhood, not birth.

"It is unfortunate that we are talking about the beginning, when in reality we do not have a good theory of something such as the beginning," the professor told AFP after the conference.

In contrast, cosmology has very good theories to explain the evolution "since the first seconds of the expansion of the universe", there are nearly 14 billion years. This is literally the first few seconds that cosmologists have discovered ... fossils.

The term is the same as in paleontology. The oldest fossils include helium particles emitted in seconds when the universe was very hot and dense. They were observed with telescopes.

These theories are well verified by observations, he says, which makes all the difference with theories concerning the strange previous phase.

"We do not have a solid test for what happened before," says James Peebles. "We have theories, but not tested."

- "I'm giving up" -

"The theoretical ideas are wonderful but, in my opinion, they become established when they pass their exam," says the professor, who has spent the last 60 years developing them.

"Any intelligent physicist can invent theories that have nothing to do with reality, we discover what theories are close to reality when we compare them to experiments, and we have no experimental evidence of this. which happened before. "

Among the cosmological theories is that of inflation, a very short phase that would have occurred before expansion. "It's a beautiful theory," Judge James Peebles. "Many people think it's so beautiful that it has to be fair, but the evidence is very sparse."

"Can I ask you not to use the term Big Bang recklessly?" Asked the end of the interview the cosmologist, after a poorly worded question.

Which term do you prefer?

"I gave up, I use Big Bang myself, although I do not like it, for years we tried to convince the community to find a better term, to no avail, so it's still the Big Bang." is unfortunate but everyone knows the name, so I give up. "

© 2019 AFP