MYTH there''s a curious pattern of dots that recurs in art around the planet and throughout history. The number varies, but commonly it''s a close-knit group of six circular spots, distinctively arranged in lines of four and two. This motif is seen in far-flung communities, from holes pierced into the gourd rattle of a Navajo tribe to a painting on a Siberian shaman''s drum. It even appears in the logo of the Japanese car manufacturer Subaru. In all of these cases, the dots represent one of the most characteristic features of the night sky: the star cluster Pleiades. This clutch of six or seven stars (the exact number depends on viewing conditions) appears close to the Sun''s annual path through the sky, and features in multiple myths and legends: in Cherokee myth, these stars are lost children; the Vikings saw them as the goddess Freyja''s hens. They are also a distinctive part of the constellation Taurus. The Pleiades sit just above the shoulder of this celestial bull, with its thrusting horns, prominent eye-the red giant Aldebaran-and another star cluster, the Hyades, splashed in a "V" across its face.

The frequent appearance of this six-spot pattern demonstrates the importance of the Pleiades in societies around the world, as well as the shared human desire to capture aspects of the starry sky in art. But there is more to this story-another example of these dots that seems, frankly, impossible. The cave of Lascaux in southwestern France is famous for its wealth of Paleolithic art: paintings and engravings of animals, thought to be twenty thousand years old, dating from the dawn of humanity. Scholars have argued over their meaning for decades. Meanwhile, barely noticed on the ceiling of its grand entrance hall, are six plain spots that match the Pleiades perfectly. Neatly painted in red ocher, they float above the shoulder of a majestic aurochs bull. At seventeen feet long, "Bull No. 18" is the largest and perhaps most recognizable painting in the entire cave.

Its striking similarity to the modern Taurus-it even has V-shaped spots on its cheek-has been known for years. Yet it goes unmentioned in guidebooks and is rarely discussed by mainstream archaeologists. Taurus is one of the earliest constellations to be described: it can be traced back through written sources nearly three thousand years to Babylonian priest astronomers who saw the Pleiades as a bristle on the back of a heavenly bull. But a star map invented by the supposedly primitive hunter-gatherers of Lascaux? The idea was not so much rejected as not talked about at all. In the last few years, however, experts in fields such as anthropology, mythology and astronomy have begun to argue for a radical reassessment of our Paleolithic ancestors'' skills, and the lasting influence of the stories they told. So in this history of humanity''s relationship with the stars, let''s start with the mystery of Bull No. 18. We''ll explore whether the artists of Lascaux could really have painted constellations, and ask why they might have cared so much about the sky.

It''s a journey that takes us to the heart of what the universe meant to the very first humans who had the ability to imagine, remember, explain and represent. The cosmos they created still shapes our lives today. On September 12, 1940, seventeen-year-old Marcel Ravidat, an apprentice mechanic, walked with three friends into the hills near his village of Montignac in southwest France. According to village legend, there were caves beneath the hills-during the wave of executions that followed the French Revolution, the AbbZ Labrousse, owner of the nearby manor, supposedly hid in one-and Ravidat wondered if they might hold treasure. A few days before, he had started to unblock a promising hole in the ground. Now, armed with a knife and a makeshift lantern, he planned to finish the job. The boys'' target was a basin-shaped depression in the ground, surrounded by pine trees and junipers and full of brambles. At the bottom was a small opening that led to a narrow, near-vertical shaft.

The boys cleared the thorns-and the remains of a donkey-and dug with their hands to widen the hole to about a foot across. They dropped down stones, and were surprised by how long they rolled and the resonance of the sound. Those brambles had been hiding something big. Ravidat, the oldest and strongest of the group, dived in headfirst and wriggled several yards through the earth before landing on a conical pile of clay and stones. He lit his lamp, which he''d made from a grease pump and a coil of string, but almost immediately lost his balance and slipped all the way to the bottom. He found himself in a large hall, about sixty feet long, and called for his friends to follow. They crossed the limestone cavern in near darkness, dodging shallow pools of water on the floor, until they reached a narrow corridor with a high, arched ceiling, like a cathedral vault. Only here did Ravidat raise his lamp, and the boys found their treasure.

Covering the white walls was an explosion of life: images from the birth of our species, pulled back into view for the first time in twenty thousand years. First, they noticed colored lines and strange, geometric signs. Then, moving the lamp around, they saw the animals. There were horses everywhere, golden with black manes, as well as black-and-red bulls, ibexes and a bellowing, antlered stag. Herds climbed the walls and tumbled across the ceiling, some defined and multicolored, others ghostly, as if falling through fog. The boys didn''t understand the full significance of what they had found, but they knew it was special, and they celebrated with leaps and cries in the trembling light. Lascaux Cave (named for that nearby manor) now ranks as one of the most spectacular archaeological discoveries in history. It is just one of hundreds of caves in southern France and northern Spain decorated between 37,000 and 11,000 years ago by anatomically modern humans who first migrated into Europe from Africa around 45,000 years ago, during the last Ice Age.

It''s a period called the Upper Paleolithic, named for the stone tools in use at the time, and it seems to have hosted an explosion in human creativity. Art from around this time is known elsewhere, too-in Indonesia and Australia, for example. But thanks to the complexity, exquisite preservation and sheer volume of its paintings and engravings-nearly two thousand of them-Lascaux is one of the finest examples. The artists at Lascaux used plant-based brushes or swabs of hair, and a palette of iron and manganese minerals, kaolin clay and charcoal sticks to cover corridors and chambers reaching over three hundred feet into the rock. Their creations provide a rare and hauntingly beautiful insight into the prehistoric human mind. Who were these early people? What did they care about, and what triggered them to create art? What was it, in effect, that made them human? In the decades since the boys'' discovery, scholars have come up with a rich parade of answers to these questions. An early idea was that the mysterious figures were simply decoration, "art for art''s sake" without any special meaning. Another suggestion was that the animals represented different clans, and that the paintings represented battles and alliances between them.

Some experts thought that the paintings were intended as magical spells, to boost the success of hunting expeditions or ward off evil spirits. In the 1960s, scholars took a statistical approach, recording how different types of figures were distributed in the caves and building theories around the patterns they saw-for example, that the horses and bison symbolize male versus female identity. Then there was Norbert Aujoulat, who perhaps came to know the paintings more intimately than anyone else. A cave enthusiast, he described himself as "an underground man." He would disappear for days at a time on solitary excursions into the French mountains, and helped to discover dozens of subterranean chambers. But he never forgot the first time he saw Lascaux, one winter afternoon in 1970. Since its discovery, the site had opened to the public and closed again: the breath exhaled by thousands of visitors per day, and the germs they tramped in, were damaging the precious paintings. Aujoulat, a twenty-four-year-old local student, joined a private tour guided by Jacques Marsal, one of the four friends led by Ravidat who had discovered the cave three decades before.

To reach the paintings, Marsal led them down a slope through a series of stone-lined entrance halls and doors, built for security, which made Aujoulat feel as if they were approaching the sacred inner space of a temple. The last door was made of heavy bronze and decorated with polished stones. Aujoulat spent only half an hour exploring the treasures beyond that door, but it was enough to set the course of his life. He was bewitched by the overwhelming sense of human presence inside the cave, powerful enough to stretch across so many thousands of years, and he set his sights on understanding how and why the paintings were created. It was nearly two decades before Aujoulat was able to fulfill his dream. In 1988, as head of the French culture ministry''s Department of Parietal Art, he began a monumental decade-long study of Lascaux Cave, from the great bulls circling the ceiling of the entrance cavern to the dense, entangled engravings in a smaller chamber called the Apse. Whereas other scholars had focused on the art, Aujoulat approached Lascaux as a natural scientist, studying every aspect of the cave from the geology of the limestone to the biology of the animals on the walls. He came to the conclusion that everyone else had missed a crucial dimension: time.

When he studied overlapping paintings where horses, aurochs and stags a.