electrical device, driven by the myriad tiny electric motors and the other electrochemical nanomachinery of cells. Viewing the world this way reveals hitherto unappreciated dangers in some modern science.
Some molecular biologists are doing research on ways of inserting genes into microorganisms in order to create new kinds of life that have never previously existed. Others are busy working out whether the cellular nanomachinery itself might be improved. Falkowski recommends that ârather than tinker with organisms that we canât reverse engineer, a much better use of our intellectual abilities and technological capabilities would be to better understand how the core nanomachines evolved and how these machines spread across the planet to become the engines of life.â
*
Just how far we are from obtaining an understanding of the evolution of the nanomachines is conveyed in Peter Ward and Joe Kirschvinkâs latest book, A New History of Life . Both authors are iconoclasts, and their book is at times breathtakingly unorthodox. Yet their ideas are at the cutting edge of many debates about the evolution of life, making their book challenging and rewarding. The work of the paleontologist is like that of a restorer of ancient mosaics: the further we go back in time, the fewer tesserae, or mosaic components, we have. Those seeking to understand the origin of the nanomachines have to work with the equivalent of just half a dozen pieces from a picture comprising tens of thousands. Time and our restless Earth have destroyed the remainder. Despite this awesome handicap, Ward and Kirschvink are convinced that, owing to the new technologies, we are at last asking the right questions.
We have a reasonably concise date for the formation of Earth â 4560 million years ago, give or take 10 million years. The half a billion years that followed, known as the Hadean Eon, were momentous. A huge asteroid slammed into the planet, forming the moon and transforming Earth into a ball of molten rock. As Earth cooled, the progenitors of the modern core and crust were formed. Earthâs oldest rocks â tiny, 4.4-billion-year-old zircon crystals from Western Australia â are the only physical evidence we have of this period. Chemical analysis reveals that they formed where ocean water was being sucked down into the mantle â the layer of the earth between the crust and the core. So we can surmise that Earth cooled quickly after the asteroid collision, and that at an early stage it had oceans.
Despite the presence of oceans, Earth was almost certainly hostile to life in the Hadean Eon. Asteroid impacts repeatedly shook the planet, boiling its oceans and changing the atmosphere. But by four billion years ago, things had begun to settle down. The 1.5-billion-year-long Archean Eon had begun, and it was over the first third of this period that the nanomachines either evolved or, as Ward and Kirschvink argue, colonised Earth from elsewhere.
As we ponder lifeâs origins, Ward and Kirschvink warn against thinking in simplistic terms like life and death, instead encouraging us to consider the ânewly discovered place in betweenâ. Lifeâs most distant origins lie in the nonliving precursor molecules for RNA, organic compounds known as amino acids. They have been found in meteorites, are presumed to be widespread in the universe, and their origins must greatly predate Earthâs origins. The nanomachines possess attributes of life, and when brought together in a cell they clearly cross the threshold into the self-regulating, replicating entity that we recognise as a living thing.
A slick layer of graphite preserved in 3.8-billion-year-old rocks near Isua, Greenland, was long believed to contain the earliest evidence of life on Earth. But recent studies reveal that the carbon composing the graphite was not formed by life at all. The next oldest evidence was long thought to be 3.5-billion-year-old microscopic
Some molecular biologists are doing research on ways of inserting genes into microorganisms in order to create new kinds of life that have never previously existed. Others are busy working out whether the cellular nanomachinery itself might be improved. Falkowski recommends that ârather than tinker with organisms that we canât reverse engineer, a much better use of our intellectual abilities and technological capabilities would be to better understand how the core nanomachines evolved and how these machines spread across the planet to become the engines of life.â
*
Just how far we are from obtaining an understanding of the evolution of the nanomachines is conveyed in Peter Ward and Joe Kirschvinkâs latest book, A New History of Life . Both authors are iconoclasts, and their book is at times breathtakingly unorthodox. Yet their ideas are at the cutting edge of many debates about the evolution of life, making their book challenging and rewarding. The work of the paleontologist is like that of a restorer of ancient mosaics: the further we go back in time, the fewer tesserae, or mosaic components, we have. Those seeking to understand the origin of the nanomachines have to work with the equivalent of just half a dozen pieces from a picture comprising tens of thousands. Time and our restless Earth have destroyed the remainder. Despite this awesome handicap, Ward and Kirschvink are convinced that, owing to the new technologies, we are at last asking the right questions.
We have a reasonably concise date for the formation of Earth â 4560 million years ago, give or take 10 million years. The half a billion years that followed, known as the Hadean Eon, were momentous. A huge asteroid slammed into the planet, forming the moon and transforming Earth into a ball of molten rock. As Earth cooled, the progenitors of the modern core and crust were formed. Earthâs oldest rocks â tiny, 4.4-billion-year-old zircon crystals from Western Australia â are the only physical evidence we have of this period. Chemical analysis reveals that they formed where ocean water was being sucked down into the mantle â the layer of the earth between the crust and the core. So we can surmise that Earth cooled quickly after the asteroid collision, and that at an early stage it had oceans.
Despite the presence of oceans, Earth was almost certainly hostile to life in the Hadean Eon. Asteroid impacts repeatedly shook the planet, boiling its oceans and changing the atmosphere. But by four billion years ago, things had begun to settle down. The 1.5-billion-year-long Archean Eon had begun, and it was over the first third of this period that the nanomachines either evolved or, as Ward and Kirschvink argue, colonised Earth from elsewhere.
As we ponder lifeâs origins, Ward and Kirschvink warn against thinking in simplistic terms like life and death, instead encouraging us to consider the ânewly discovered place in betweenâ. Lifeâs most distant origins lie in the nonliving precursor molecules for RNA, organic compounds known as amino acids. They have been found in meteorites, are presumed to be widespread in the universe, and their origins must greatly predate Earthâs origins. The nanomachines possess attributes of life, and when brought together in a cell they clearly cross the threshold into the self-regulating, replicating entity that we recognise as a living thing.
A slick layer of graphite preserved in 3.8-billion-year-old rocks near Isua, Greenland, was long believed to contain the earliest evidence of life on Earth. But recent studies reveal that the carbon composing the graphite was not formed by life at all. The next oldest evidence was long thought to be 3.5-billion-year-old microscopic
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