The condemned universe? Big Crunch's shock theory resurfaces

Cosmology is boiling these days. After The new image of fossil radiationit is the turn of the Euclid space telescope and the desi consortium (Dark Energy Spectroscopic Instrument) to give results on the expansion of the universe and the force that generates it: black energy.

This expansion is so powerful that black energy would correspond to 70 % of the energy content of the universe. It was discovered in 1998 that it accelerated over time and constantly.

By observing 15 million galaxies in three years, the desi is sowing today: black energy may be in decline for about 2.5 billion years.

Dark energy would possibly slow down

“When you combine all cosmological data, they promote an acceleration of the expansion of the slightly larger universe around 7 billion years in the pastdetails Arnaud de Mattia, a physicist at CEA having participated in the analysis of Desi's data. And this acceleration has tended to decrease for 2.5 billion years ”.

The fate of the universe could tend towards a big crunch

This force capable of repelling the dimensions of the universe and propeling the galaxies far from each other is also that which allows us to envisage the way in which the universe will end. The evolution of the density of this dark energy over time is therefore crucial. Three hypotheses are generally retained in this context:

• 1/ The thermal death of the universe or Big Freeze. The universe would extend so much that its temperature would decrease until the absolute zero. It is a very slow death where everything would become dreary and cold, a direct consequence of thermodynamics.

• 2/ Big RIP (large tear in French) would be the consequence of black energy which would continue to accelerate. On cosmological durations a little shorter than the Big Freeze, that is to say in 15 to 20 billion years “only”, the expansion would completely dominate the other forces. Even the atoms of our body would end up falling apart after we would have seen the stars and the planets go far, then the sun would tear itself. Not nice, but poetic …

• 3/ Big crunch is a kind of reverse from Big Bang. In the event that black energy tends to weaken sufficiently, gravity could then regain control over the universe and direct the galaxies against each other, clusters of galaxies against each other, superamas, etc. The sky would then become very clear, even at night. And then, boom! Following the rate of slowdown in black energy, a big crunch would occur in a few tens of billions of years.

This third scenario, which had been rather excluded in recent times by the community of astrophysicists and cosmologists, would become a possible future in the event that the results of Desi about a slowdown was confirmed. Euclid, the ESA space telescope, also examines the clusters of galaxies in order to understand the nature and evolution of black energy.