THE role of bubbles in the creation of life on earth is one of the newest approaches to solving the scientific mystery that is probably second in importance only to the problem of how the universe itself began. No one is suggesting that bubbles might explain everything. But in a new hypothesis receiving close attention, the multitudes of bubbles forming on the surface of the primordial seas must have collected chemicals and concentrated them for synthesis intocomplex molecules. Eventually, through multi-stage reactions constantly repeated by uncounted generations of bubbles, the molecules grew in size and ambition, ready for the transition to living, reproducing cells. The bubble hypothesis was described recently by Louis Lerman, a geophysicist at Lawrence Berkeley Laboratory in California. Biologists said the concept seemed sound, was based on well-established physical principles and was certainly worth detailed study. The earth is about 4.5 billion years old, and the earliest unequivocal fossil evidence of living organisms is dated at 3.5 billion years. According to Lerman's hypothesis, some time before those fossils the earth was already seeded with prebiotic organic compounds, composed mainly of carbon atoms, which would later be synthesised into the building blocks of living organisms. The initial organic material could have been delivered from space by falling meteorites, which are known to contain such molecules, or spewed out by volcanic eruptions - or it could have come from both sources. Once dispersed in the air and the sea, then covering almost the entire earth, the simple organic chemicals were trapped by underwater bubbles and atmospheric aerosols and droplets. When the bubbles rose to the surface and burst, according to the hypothesis, the more concentrated organic material was ejected into the air and carried upward by winds. Atmospheric chemistry, triggered by lightning or solar ultraviolet radiation, then altered the material into complex organic molecules that precipitated back down to earth as rain and snow. Raindrops and snowflakes, as well as the wind and waves, created more bubbles on the sea surface, starting the cycle all over again. Lerman called the cycle ''a natural reactor for prebiotic chemistry''. As he remarked, ''It may not have been a global primordial soup which was the key to chemical evolution, but the primordial bubble.''
