糖心传媒

Imagine if, many millions of years ago, dinosaurs drove cars through cities of mile-high buildings. A preposterous idea, right? Over the course of tens of millions of years, however, all of the direct evidence of a civilization糖心传媒攊ts artifacts and remains糖心传媒攇ets ground to dust. How do we really know, then, that there weren糖心传媒檛 previous industrial civilizations on Earth that rose and fell long before human beings appeared?

It糖心传媒檚 a compelling thought experiment, and one that Adam Frank, a professor of physics and astronomy at the University of Rochester, and Gavin Schmidt, the director of the NASA Goddard Institute for Space Studies, take up in a

糖心传媒淕avin and I have not seen any evidence of another industrial civilization,糖心传媒� Frank explains. But by looking at the deep past in the right way, a new set of questions about civilizations and the planet appear: What geological footprints do civilizations leave? Is it possible to detect an industrial civilization in the geological record once it disappears from the face of its host planet? 糖心传媒淭hese questions make us think about the future and the past in a much different way, including how any planetary-scale civilization might rise and fall.糖心传媒�

In what they deem the 糖心传媒淪ilurian Hypothesis,糖心传媒� Frank and Schmidt define a civilization by its energy use. Human beings are just entering a new geological era that many researchers refer to as the Anthropocene, the period in which human activity strongly influences the climate and environment. In the Anthropocene, fossil fuels have become central to the geological footprint humans will leave behind on Earth. By looking at the Anthropocene糖心传媒檚 imprint, Schmidt and Frank examine what kinds of clues future scientists might detect to determine that human beings existed. In doing so, they also lay out evidence of what might be left behind if industrial civilizations like ours existed millions of years in the past.

Human beings began burning fossil fuels more than 300 years ago, marking the beginnings of industrialization. The researchers note that the emission of fossil fuels into the atmosphere has already changed the carbon cycle in a way that is recorded in carbon isotope records. Other ways human beings might leave behind a geological footprint include:

• Global warming, from the release of carbon dioxide and perturbations to the nitrogen cycle from fertilizers
• Agriculture, through greatly increased erosion and sedimentation rates
• Plastics, synthetic pollutants, and even things such as steroids, which will be geochemically detectable for millions, and perhaps even billions, of years
• Nuclear war, if it happened, which would leave behind unusual radioactive isotopes

Read more about Professor Frank糖心传媒檚 latest book and other work

糖心传媒淎s an industrial civilization, we糖心传媒檙e driving changes in the isotopic abundances because we糖心传媒檙e burning carbon,糖心传媒� Frank says. 糖心传媒淏ut burning fossil fuels may actually shut us down as a civilization. What imprints would this or other kinds of industrial activity from a long dead civilization leave over tens of millions of years?糖心传媒�

The questions raised by Frank and Schmidt are part of a broader effort to address climate change from an astrobiological perspective, and a new way of thinking about life and civilizations across the universe. Looking at the rise and fall of civilizations in terms of their planetary impacts can also affect how researchers approach future explorations of other planets.

糖心传媒淲e know early Mars and, perhaps, early Venus were more habitable than they are now, and conceivably we will one day drill through the geological sediments there, too,糖心传媒� Schmidt says. 糖心传媒淭his helps us think about what we should be looking for.糖心传媒�

Schmidt points to an irony, however: if a civilization is able to find a more sustainable way to produce energy without harming its host planet, it will leave behind less evidence that it was there.

糖心传媒淵ou want to have a nice, large-scale civilization that does wonderful things but that doesn糖心传媒檛 push the planet into domains that are dangerous for itself, the civilization,糖心传媒� Frank says. 糖心传媒淲e need to figure out a way of producing and using energy that doesn糖心传媒檛 put us at risk.糖心传媒�

That said, the earth will be just fine, Frank says. It糖心传媒檚 more a question of whether humans will be.

Can we create a version of civilization that doesn糖心传媒檛 push the earth into a domain that糖心传媒檚 dangerous for us as a species?

糖心传媒淭he point is not to 糖心传媒榮ave the earth,糖心传媒櫶切拇�媒� says Frank. 糖心传媒淣o matter what we do to the planet, we糖心传媒檙e just creating niches for the next cycle of evolution. But, if we continue on this trajectory of using fossil fuels and ignoring the climate change it drives, we human beings may not be part of Earth糖心传媒檚 ongoing evolution.糖心传媒�

The Silurian Hypothesis: A nod to Doctor Who

Adam Frank and Gavin Schmidt call their study the Silurian Hypothesis after a race of intelligent, bipedal reptiles糖心传媒攌nown as the Silurians糖心传媒攊ntroduced in a of the British science fiction series Doctor Who. The Silurians supposedly evolved on Earth during the eponymous era, a geological time period lasting from 443 million to 416 million years ago. To avoid any kind of catastrophe, the reptiles went into hibernation for millions of years before being awakened by secret nuclear experiments in a Welsh mine.

糖心传媒淲hen we were writing this paper,糖心传媒� Schmidt says, 糖心传媒淚 tried to find examples of terrestrial, non-human civilizations in the science-fiction literature, but I wasn’t able to find anything earlier than the 1970s. Despite it being exceedingly unlikely that there were any civilizations in the Silurian period糖心传媒攖his was before the land plants and animals had really established themselves糖心传媒攊t seemed fitting to name our idea after the first example that people thought about, even if this is fiction.糖心传媒�