It’s been a while since we humans felt so vulnerable, that nature didn’t put us in our place. It may not be the best time to read a Brian Greene book about the end of time. A physicist and mathematician, Ph.D. from Oxford University and professor at Columbia University, Greene is an expert in string theory and a devoted science popularizer. His last book, Until the end of time (Critica), is a journey through the evolution of the universe in which human affairs are very small, if not insignificant.

Why should we read about the brevity of existence, our world, and ourselves? “A prominent theme of my book is the poetic interplay between the fate of the universe and the fate of the individual; both, in their own way, exist only for a finite duration. And while that recognition impacts each of us in different ways, what is universal is that the impact is persistent and deep. Even more so, during the tragic crisis we are experiencing today, when we do not have to dig deep to discover the fragility of life. The recognition of that fragility, as I expose in the book, makes life even more precious”, Greene responds to El Independiente.

While the Columbia University professor is a life enthusiast, he gives little hope that we humans, with all our dramatic and historical existence and intensity, will leave any mark on the universe. “When you look at the universe as a whole, from the beginning of time to as close as science can take us to its end, you realize that nothing is eternal: not galaxies, not stars, not planets, not life, or conscience.

So as much as we long to leave a legacy, a trace of having been here, any such trace will be erased by the winds blowing across the sands of time,” he explains.

These forceful certainties leave us open the field between surrendering to carpe diem or pushing ourselves to collective suicide, but Greene still shows us another existential abyss when he introduces us to the Big Bounce theory, according to which our vast universe is in an infinite cycle, a theory that has been gaining weight over the years. “An exciting possibility is that the Big Bang may not have been the beginning of the universe, but instead could have been a bouncing of space outward after an earlier phase of inward contraction.

So-called “bouncing cosmology” can shake space in a different way than more traditional theories, leading to a different collection of gravitational waves. In principle, the footprint of such primordial gravitational waves could one day be observed, providing insight into the origin and evolution of the universe,” he states.

Black holes
Gravitational waves and black holes are the aspects of research that are showing the most progress. Black holes have been the protagonists of the recent Nobel Prize in Physics, and we asked Greene why they are so important in our understanding of the universe.

“We learn the most when we push our theories to the most extreme domains possible, and black holes have long provided one such example. In the early part of the 20th century, black holes were a purely mathematical consequence of Einstein’s general theory of relativity, which scientists explored to illuminate the most extreme contortions of space and time. Now black holes are also an observation quest, as ambitious scientists have found ways, directly and indirectly, to observe black holes in the cosmos. In the future, many of us anticipate that the next leap in our understanding will come from fully understanding black holes at the level of quantum mechanics.”