[...]... herrings It will be vital for these explorers to work out the geological blueprints for this planet, for some part of us will have become geology What remains of us, though, will inhabit a brief geological instant that will seem lost among many millions of other such instants that have succeeded one another in the long history of the Earth On the other hand, there might be reason to suppose that the. .. in their investigations Further, to understand the pattern of life that they will find and to illuminate its relation to the solid planet itself, they will need to understand the history of the living organisms and of the planet that they inhabit That history, they will soon realize, covers the surface of the Earth as it covers no other body in this solar system Litters it, in fact For the Earth is... extinct The world will then go on as before Once a geological age or two has passed, there will be nothing but the odd bone or gold ring to show that we were ever here 1 PERSPECTIVE In this scenario, comparison with the dinosaurs is apt They were the top predators of their day, as our single species is now But consider, also, the differences between us and the dinosaurs The dinosaurs existed on this Earth. .. dioxide, recombining them into complex organic molecules which they use to build themselves, releasing oxygen into the atmosphere as a by-product And, by further sophisticated chemical sleight-of-hand, these plants extract the stored energy in some of their newly synthesized molecules of carbohydrate by reacting them with oxygen, converting them back to carbon dioxide and water, and using the energy derived... out Like other organisms, we may leave fossil evidence, in the form of our bodies and traces of our activity in the rock record, but this record will inherently be biased, and tricky to read Human activities have also been changing the Earth s landscape, and so the way in which rocks themselves are being formed They have also been changing the Earth s climate and biosphere Will the effects of these changes... dislocation in the rock strata, another inheritance from these mountains’ violent past The team had to climb halfway up that vertiginous ravine But they had good balance, these explorers, their tails and sharp claws helping them scramble up the near-vertical rocky surfaces The hard material of the stratum formed a natural overhang, and, once they had climbed over that, they could explore in some comfort There... streamlined as the dolphins of today and the ichthyosaurs of yesteryear Among them, fish—both bony fish and the cartilaginous sharks—might still be prominent in the oceanic ecosystem Perhaps, though, as populations of the latter are now plummeting—vertiginously so in the case of the bigger sharks, because of hu9 100 MILLION YEARS AD man over-fishing—this might give a chance to other creatures, perhaps the. .. more of the continents were submerged So which future to choose—global hothouse or icehouse? One can simply use historical precedent Hothouse times were more common than icehouse times in the Earth s geological past One can also invoke astrophysical inevitability: the sun will be very slightly hotter, and so will have 8 100 MILLION YEARS AD pushed the Earth just that little bit closer to the point at... ecosystem, as in the details of its almost in nite variety Thus, they will see that the base of this immense diversity is the plant life, capturing a portion of the light from the sun and reflecting the unused portion of the spectrum back into space (aha they may say as they work that out—so that’s where the green colour of this planet comes from) Then using the energy from that captured light to split... For the Earth is active It is not just an inert mass of rock, an enormous sphere of silicates and metals to be mined by its freight of organisms, much as caterpillars chew through leaves Nor will it be inert, a hundred million years into the future It is a dynamic system, powered from inside by the heat generated from the radioactivity within its interior The internal radioactivity of the Earth is in .