Voyage of Discovery: From the Big Bang to the Ice Age

 In 1940 during the early days of World War II, Marcel Ravidat, an 18-year-old boy living in the small village of Lascaux in southwestern France, set out with three friends and only a lantern to explore a dark entrance in the ground exposed when a tree was uprooted. An old woman living near the hole claimed it was an entrance to a passage formed in the Dark Ages.

 The hole was about three feet wide and fairly deep judging from the sound stones and dirt made as they hit the floor below. Marcel worked his way down the long, narrow, steeply inclined tunnel, falling headfirst much of the way. The other boys followed. When Marcel lit the lamp, they found themselves standing in front of wall after wall of crude but spectacular figures of prehistoric animals. On the domed ceilings they found a vast array of bulls, galloping horses with long hair, herds of deer, and bison that had been extinct in Europe for thousands of years. Painted in reds, yellows, and browns with many of the figures outlined in black, they presented a breathtakingly colorful panorama.

 The boys' elation was beyond description. They agreed to say nothing to anyone until they could come back the next day with better equipment to finish the exploration. But who could blame them for not holding on to their vow? It did not take long for the news to spread, as the boys worked their way through the cave the next day.

 The authorities of the region decided to call in experts on Paleolithic art. Meanwhile, the boys camped in front of the cave for ten days to protect it while they waited for the anthropologists.

 The cave at Lascaux is often referred to as the "Sistine Chapel of the Paleolithic" because of the splendor of the 17,000-year-old drawings (Figure 0‑1). Hidden and protected almost from the day they were first drawn; the art is in a remarkable state of preservation. Many caves with drawings like those in Lascaux have been discovered throughout Europe, especially in northern Spain and southern France. The cave art, which includes creatures like the woolly mammoth, rhi­noceroses, birds, fish, and lions, ranges in age from about 12,000 to 40,000 years. Some of the oldest cave drawings were discovered in the latter part of 1994 in a cave at Chauvet, France.

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 At several cave sites, the walls below the drawings are pitted with holes from spears thrown by the early humans. Although there can be no doubt that much of the art was painted for religious, ritual, and esthetic purposes, the chipped walls seem to indicate that some of the art was drawn simply to recreate the hunt: the pictures serve as symbols of the creatures they hunted. If in fact this is true, the drawings represent a remarkable step in the history of life. Finally, after 3.8 billion years of evolution, apparently there was an animal capable of abstract thought – symbolic in many respects. Finally, there were beings with rich enough mental pow­ers to step along a course of reason and understanding. A course that would eventually give them a fair understanding of how they came to be. It is true, the course did not come easily – there were many setbacks along the way – but in just 20,000 years or so, a mere flash in time relative to the age of the universe, these creatures would come to understand their origins in a universe that was essentially terra incognita prior to the journey of scientific discovery.          

 It is a story about curious creatures who kept probing the unknown. Although there will always be terra incognita, the big picture is now well understood. Just think, we are living in a time when, for the first time, the story of the last 13.8 billion years can be told – the whole history of our universe, from the Big Bang and galaxy formation to the Ice Age and the great mass extinctions, – from the origin of life to the evolution of the primates. Information has been gathered by thousands of scientists over the centuries, but it was not until the 1990s and the early 2000s that research filled in some rather large unknowns, thus enabling the compilation of the story I present in this book.

 The book is really a story of how the essence of the universe – the matter and space/time within it – came to be and how it has been and will be, recycled over and over again. It is enchanting and, yet, at the same time frightening to realize that our bodies are only temporary resting places for the billions of atoms that combine to make each one of us unique individuals. Some of the atoms have a longer res­idency than others, but all will be passed on to the future. The old biblical phrase "dust to dust" comes to mind. The carbon in my brain, for instance, may become part of another entity someday – perhaps a distant human descendant or other animal, and the iron that flows through my veins may become part of a steel-plated tank used in some future war. When we die, we certainly can't take it with us.

 But it's more than just "dust to dust." We are all part of a grand recycling program. Maybe one of the calcium atoms in my bones was part of a tooth in the first creature on land and before that was recycled from a 600-million-year-old limestone deposit. The trip all atoms have taken has been an immense journey. This is all a bit unsettling. But it is com­forting somehow to understand our origins. I don't just mean in the Darwinian sense; I mean the origin of the material that we are made of and the journey through time that it has taken to reach our bodies (even though we are only a temporary collection site).

 We can go back to our roots. Science is like a time machine that can take us back to about the first 10^-43 of a second of our cosmological roots within the bowels of the Big Bang. In a way because of the discoveries of science, we can go back and witness the birth of the universe and all that has happened in the 13.8 billion years since the Big Bang occurred. I don't mean to imply that science knows all, far from it. But Einstein did once say, "The most incomprehensible thing about the universe is that it is comprehensible."

 We are about to embark on a truly immense journey; the history of the uni­verse, earth, and life, and of the men and women who made that understanding possible – the discovery of terra incognita.