Cosmological odyssey
Reviewed by Kuldip Dhiman

The Edge of Reason: Dispatches from the Frontiers of Cosmology
By Anil Ananthaswamy.
Penguin Books.
Pages 322. Rs 399.

IN the realm of physics, there are pure theorists and there are experimenters. Theoretical physicists study phenomena in nature, observe regularities, and then come up with mathematical models and theories that explain it. Their aim is to rationalise, explain and predict physical phenomena so that we could harness nature to our advantage.

No matter how accurate a scientistís abstract theorising might be, it is not accepted as theory until it is verified experimentally. There was a time, when both theory and experiment were performed usually by the same person, but now the theories are so complex and the experiments so complicated and expensive that it is impossible for the same person to come up with a hypothesis and also test it.

In The Edge of Reason: Dispatches from the Frontiers of Cosmology, Anil Ananthaswamy, consulting editor for New Scientist and contributor for journals like National Geographic, gives us an overview of how theories are developed and also how they are experimentally tested. In this engaging first-person account that reads like a travelogue, he takes us on a cosmological odyssey to the remote corners of the world, where some of the most audacious theories are being tested empirically.

Among the handful of science writers of Indian origin, Ananthaswamy writes with a rare gift of making highly theoretical and technical concepts comprehensible to the lay reader. He begins by giving a theoretical background to various theories of physics, and then takes us to the place where they are being tested. All the while he keeps musing about the mysteries of nature: How did the universe come into being? Why is the universe expanding? Is this the only universe in existence? What is dark matter? What is dark energy? What are neutrinos? What is the origin of mass? What happened to the antimatter that should have been produced along with matter after the big bang?

Our first stop is Mount Wilson, Pasadena, where there is a telescope that enabled scientists to confirm that our universe is far bigger than we had earlier imagined. We are then taken to an abandoned mine in Minnesota, called the Soudan Mine. It is where experiments are being conducted to look for dark matter that is inferred to exist from gravitational effects on visible matter and background radiation, but is undetectable. "Along with dark matter," says Ananthaswamy, "there is now another puzzle: dark energy. Together they form the bulk of the universe, about ninety per cent. In other words, have no clue about ninety per cent of the universe." Using the four massive telescopes at Paranal, Chile, scientists are working overtime to solve this mystery.

As we turn the pages, we visit Lake Baikal in Siberia, the Atacama Desert in the Chilean Andes, Mauna Kea in Hawaii, the Large Hadron Collider near Geneva, the deserted Karoo in South Africa, the frozen expanses of Antarctica, and the Hanle Valley in the Indian Himalayas where scientists are trying to unravel the most mysterious phenomena that that baffle us.