Big Crunch, Big RIP, Big Freeze … How will the universe end ?
– News of February 10, 2019 –
According to the Big RIP model, the accelerated expansion of the universe continually distances large structures and small structures until even subatomic particles are so far apart that none of the fundamental forces can act. The space-time itself ends up being torn, which means the end of time. To function, this model needs a form of dark energy that has an increasing importance over time. This is exactly what distance measurements carried out on quasars. However, it is still far too early to exclude other models of evolution of the universe.
The Big Crunch model is the opposite of the Big RIP model. According to this model, the expansion of the universe will eventually slow down and then reverse. Gravity will bring all the elements of the cosmos back to a final singularity, like a kind of inverted Big Bang. But this model is impossible if we accept the existence of dark energy. However, it can not yet be totally rejected because dark energy could be an error of measurement or interpretation. It could also change over time, and perhaps lose intensity. This would lead after a few hundred or trillions of years to a Big Crunch.
Between these two models, we can imagine an intermediate model where the density of dark energy does not increase over time. Galaxies would then continue to move away from each other faster and faster but gravitationally related systems like the solar system would not be affected. In the very long term, according to the Big Freeze model the universe would face a thermal death where all the material would end up in different black holes. Black holes would continue to produce Hawking radiation for a few hundred billion years until they evaporated.
All these models are still very theoretical. This is why it is essential to progress in our understanding of dark energy and the evolution of the universe on a large scale.
Picture by Wikimedia Commons – ESO / VISTA / J.Emerson