{"id":180424,"date":"2025-06-13T06:44:10","date_gmt":"2025-06-13T06:44:10","guid":{"rendered":"https:\/\/www.europesays.com\/uk\/180424\/"},"modified":"2025-06-13T06:44:10","modified_gmt":"2025-06-13T06:44:10","slug":"what-if-we-werent-the-first-advanced-civilization-on-earth","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/uk\/180424\/","title":{"rendered":"What If We Weren’t the First Advanced Civilization on Earth?"},"content":{"rendered":"

\"\"<\/a>Credit: ZME Science\/SORA.<\/p>\n

In the grand sweep of Earth\u2019s four-billion-year history, 300 years is barely a blink. And yet, that blink \u2014 our industrial era \u2014 has already reshaped the atmosphere, oceans, and sediments. If civilization collapsed tomorrow, would anything of us remain 100 million years from now? Could some alien beings visiting Earth in the future ever tell that this planet was inhabited by an advanced civilization? More startling still: if another civilization once existed on Earth long before us, could we even tell?<\/p>\n

This question lies at the heart of the Silurian Hypothesis \u2014 a playful yet serious scientific proposition by NASA climate scientist Gavin Schmidt and astrophysicist Adam Frank, detailed in a 2018 paper in the International Journal of Astrobiology<\/a>. The name nods to the Silurians, a fictional species of ancient intelligent reptiles from Doctor Who, but the premise is grounded in geology, astrobiology, and climate science.<\/p>\n

\u201cWe are not however suggesting that intelligent reptiles actually existed in the Silurian age,\u201d the authors clarify in their paper, just to be sure no one misreads them. \u201cNor that experimental nuclear physics is liable to wake them from hibernation.\u201d<\/p>\n

A Civilization Lost to Time?<\/p>\n

At its core, the Silurian Hypothesis asks: if an industrial civilization arose millions of years ago \u2014 say, during the Devonian or the Paleocene \u2014 would we find any trace of it today?<\/p>\n

According to Schmidt and Frank, the odds are slim.<\/p>\n

For one, the geological record is woefully incomplete. Ocean crust, where much sediment settles, recycles every 170 million years or so. On land, surface preservation is even rarer. \u201cThe current area of urbanization is less than 1% of the Earth\u2019s surface,\u201d the researchers note, and ancient surfaces that remain intact are scarcer still.<\/p>\n

Even human fossils \u2014 just a few hundred thousand years old \u2014 are hard to come by. So, for a civilization that existed 10 or 100 million years ago, the chance of finding fossilized bones or a lost city is vanishingly small.<\/p>\n

Yet, there\u2019s another way to detect such a presence: its planetary footprint.<\/p>\n

Ghosts in the Sediment<\/p>\n

\"\"<\/a>Credti: Meteorolog\u00edaenRed.<\/p>\n

If a civilization had industry, it likely burned energy, changed land use, and altered the atmosphere. These changes could leave subtle markers in the rock record \u2014 what the scientists call \u201cgeochemical fingerprints.\u201d<\/p>\n

Our own civilization, brief as it is, has already left such a mark. Carbon dioxide levels have surged, oceans have warmed and acidified, and plastic particles are raining into marine sediments. Persistent synthetic chemicals, like PCBs, and even radioactive isotopes from nuclear tests may linger for millions of years.<\/p>\n

\u201cThe longer human civilization lasts, the larger the signal one would expect in the record,\u201d the authors write. But that raises a paradox: \u201cThe more sustainable a society\u2026 the smaller the footprint.\u201d<\/p>\n

A long-lived, solar-powered civilization might leave hardly a trace. By contrast, a short-lived one \u2014 fueled by fossil carbon \u2014 would leave a distinctive isotopic spike, just as humans are doing now.<\/p>\n

As they scoured Earth\u2019s geological past, Schmidt and Frank identified events that eerily resemble today\u2019s Anthropocene. Chief among them: the Paleocene-Eocene Thermal Maximum<\/a> (PETM), a rapid global warming event 56 million years ago, triggered by a mysterious pulse of carbon.<\/p>\n

During the PETM, global temperatures jumped by 5\u20137\u00b0C, ocean acidity rose, and mass extinctions rippled through the deep sea. Some metal levels spiked, and erosion intensified \u2014 features that mirror human-driven changes today.<\/p>\n

There are others: Ocean Anoxic Events in the Cretaceous and Jurassic left behind black shale deposits and strange chemical signatures. In some cases, they also coincided with large carbon isotope anomalies \u2014 just like today.<\/p>\n

Still, those ancient episodes are generally linked to volcanic activity or tectonic upheaval. To claim they came from a vanished civilization would require extraordinary evidence. Frank and Schmidt themselves don\u2019t really believe any industrial civilization existed prior to that of humans. <\/p>\n

\u201cWe are aware that raising the possibility of a prior industrial civilization\u2026 might lead to rather unconstrained speculation,\u201d the authors caution. \u201cCare must be taken not to postulate such a cause until actually positive evidence is available.\u201d<\/p>\n

Why It Matters for Today \u2014 and for the Stars<\/p>\n

This thought experiment may have real implications. It highlights how little we know about the long-term survival of civilizations \u2014 ours included. If industrial civilizations tend to collapse quickly, their geological legacy might be thin. We might never find a trace of them, just like countless human societies \u2014 along with their language, customs, stories, and inventions \u2014 have been lost across history.<\/p>\n

It also reframes how we search for intelligent life elsewhere. The famous Drake Equation<\/a>, which estimates the number of communicating civilizations in our galaxy, includes a term for how long such civilizations last. If advanced societies frequently self-destruct \u2014 or shift to sustainable models that leave little trace in the geological record \u2014 then the odds of detecting them plummet.<\/p>\n

Frank and Schmidt urge scientists to think creatively: \u201cAre there other classes of compounds that will leave unique traces in the sediment geochemistry on multi-million year timescales?\u201d they ask. Could deep drilling on Mars or Venus reveal similar fingerprints?<\/p>\n

The Silurian Hypothesis is not about proving an ancient lost civilization existed. As we\u2019ve seen, it would be almost impossible to tell from very subtle geological traces. Rather, it\u2019s more about asking what signs civilizations leave behind \u2014 and what that tells us about our own.<\/p>\n

\u201cWhile we strongly doubt that any previous industrial civilization existed before our own,\u201d the authors conclude, \u201casking the question in a formal way\u2026 raises its own useful questions related both to astrobiology and to Anthropocene studies.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"Credit: ZME Science\/SORA. In the grand sweep of Earth\u2019s four-billion-year history, 300 years is barely a blink. And…\n","protected":false},"author":2,"featured_media":180425,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3844],"tags":[74269,74270,70,74271,413,16,15],"class_list":{"0":"post-180424","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-ancient-civilizations","9":"tag-civilization","10":"tag-science","11":"tag-silurian-hypothesis","12":"tag-space","13":"tag-uk","14":"tag-united-kingdom"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@uk\/114674706980637885","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/180424","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/comments?post=180424"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/posts\/180424\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media\/180425"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/media?parent=180424"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/categories?post=180424"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/uk\/wp-json\/wp\/v2\/tags?post=180424"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}