In the history of space exploration, many theories about its state and development have been put forward. One of the leading cosmologists of modernity, Sean M. Carroll, explained in an exclusive interview for Naked Science the essence of the most universally accepted model for the development of the universe.
In 1998, two independent projects – the Supernova Cosmology Project and the High-Z Supernova Search Team – found that the universe was not only expanding, as Edwin Hubble showed in the late 1920s, but is also accelerating.
It is not easy to register this phenomenon, since it requires a long time to observe the same object. Observing distant galaxies, astronomers and astrophysicists can see that they are moving away. The speed at which these galaxies move can be recorded. Then, if, after a while, we return to monitoring these same objects, it turns out that they began to move away faster. And the further away from us the galaxy, the faster it moves away from us.
“It is a question of the cosmological constant, of vacuum energy – the idea expressed by Einstein. According to her, in the empty space lies energy. It pushes space, speeds up galaxies that move away from us, “explains Dr. Carroll, a physics research professor at the California Technical Institute (Caltech). – Vacuum energy is curious because it does not change. Do not dilute in the process of expanding the universe. ”
According to Professor Carroll, in contrast to all known types of matter and radiation, the number of which on any area of space decreases with its increase, the vacuum energy remains the same for every cubic centimeter, regardless of the degree of expansion of space. In other words, the more space we get, the more we get the vacuum energy.
Dr. Carroll argues that if this trend does not change in the future, then the universe will be forever stretched and expanded. According to the current models constructed from the latest cosmological data, the space does not collapse back into the singularity – the Great contraction – precisely because of the cosmological constant. As a result, many billions of billions of years later, the Universe is waiting for a future in which the stars will exhaust all their fuel reserves and finally cease to burn, plunging it into eternal darkness. According to the professor, all objects in space are separated from each other so much that the universe, in essence, will become an empty space.
“This is the simplest interpretation of what we know about the universe and its fate. There can be different things. Dark energy can experience a phase transition and disappear, and then zero or negative energy can appear in empty space – and everything is capable of collapsing, “says Carroll. – It is curious that we think of the universe as something old, because it is 14 billion years old. But we are very mistaken. The universe is very young – compared to how old it will end up. “