“Inside every organ, cell, and piece of DNA in our bodies lie over 3.5 billion years of the history of life”, writes Shubin, whose new book aims to extend his argument beyond the history of life on earth, all the way back to the birth of the universe, some 13.7 billion years ago. It’s an ambitious thesis – that our biology, including our consciousness, was shaped by the birth of stars and the movements of celestial bodies – but Shubin unearths plenty of supporting evidence, such as the way that our internal body clocks were pre-set by a planetary catastrophe that occurred around a billion years before the emergence of life. Long-term experiments on sleep cycles have shown how our cellular clocks run on 24-hour rhythms, which require resetting whenever we cross a time zone (hence the trauma of jet lag), and which adjust themselves continually to the changing light of the seasons. All this is due to the earth’s 23.5 degree axial tilt, the consequence of a collision with a Mars-sized asteroid some 4.5 billion years ago, the impact of which knocked our planet off-centre while leaving it with a tide-creating moon. The days, meanwhile, grow ever longer as the spinning earth is slowed by the drag of the oceans: twenty-second-century days will be two milliseconds longer than they are now, an imperceptible rate of planetary change to which our inner clocks can easily adjust.
more from Richard Hamblyn at the TLS here.