White Holes by Carlo Rovelli
Rovelli writes with enthusiastic reverence about our amazing universe. Marvelling at our scientific advances, he emphasizes the recurring need to change our minds about what we thought we knew. This is challenging, “and the difficulty lies not so much with the new concept as it does with becoming liberated from old ones.”
Expressing himself with poetic elegance, Rovelli explains and diagrams black holes and describes the related theoretical phenomenon of white holes, which resemble their negative reverse mirror image.
Thinking about such matters raises other issues. The fact that the foundational physics equations say nothing about time invites intriguing questions.
“What makes the past and the future different?” Current science suggests that in some cases, time can reverse directions, leading us to wonder, “Why do we remember the past and not the future? Why is it possible to decide what we shall do tomorrow, but not what we did yesterday?”
Ideas like reversible time sound utterly strange. Yet, the scientist cautions, “we should not have blind confidence in habitual ideas: the world is stranger and more varied than we imagine.”
The scientific answer to the arrow of time question concerns heat and disequilibrium. “Heat emission,” Rovelli tells us, “is the most characteristic of the irreversible processes…that occur in one time direction and cannot be reversed.” The universe is in a constant state of disequilibrium, without which “our very thoughts could not exist.” Dissipating energy, our senses too contribute to the unidirectional and irreversible arrow of time.
Scientists spend a lot of time arguing and defending their theories. Like the rest of us, they are subject to human concerns about reputation. Attracted by the security of clinging to well-established beliefs, they seek “abstruse ways of saving the dogma.” In the end, though, the aim of doing science is “not to convince those around you, the aim is to truly understand.”
Clarity, Rovelli assures us, “will find its way, following its own course, in its own time.” With “infinite humility” and also “infinite arrogance,” we find our way “‘along the solitary plain’” seeking to win new knowledge. Though we look for absolute truth, “we have access only to perspectives.” Yet our limitations and impermanence are the very reasons that life is “so light and sweet.”
Besides being informative, this book is erudite and poetic. A native of Verona, where Dante lived and wrote, Rovelli ingeniously parallels his scientific conundrums with the stages of the journey described in The Divine Comedy. He also traces for his readers a brief history of discoveries in physics, beginning with ancients Anaximander, Aristotle and Aristarchus. It was the ancient astronomer Hipparchus, he tells us, who pioneered the concept of “seeing with the mind’s eye.” Today this would be described as engaging in thought experiments.
Making reference to Zhuangzi, Rovelli ponders the limitations of western science, which needs the addition of analogy, a central way of thinking from the East. A scientific discovery, he says, brings a joy analogous to that experienced when we encounter a great work of art. It “suggests that there are other ways of conceptualizing the impalpable fabric of reality.”
“True love stories only open, never close,” says Rovelli. Thus the fascinated scientist “looks toward the mystery, trying to read its signs.”