Humans, we’re not good with time. Let me qualify that: we’re good with short time, like how long until lunch or how long ago did the Mets win the World Series. Usually, if something happened within your lifetime, the conceptualization of that duration of time isn’t too bad. Even when you get older and it seems like 1995 wasn’t 30 years ago, you still can wrap your head around the fact that idea.

Dive Back in Time

When time gets longer, things get harder. What was happening in your home town 100 years ago? That is only looking back to 1925. There are still people alive who were born before 1925. We had car, planes, vaccines – all features of modern society. Things were different, but not unrecognizably so.

How about 1,000 years ago? That would be 1025 CE. Any idea what was going on then? If you’re like me in the American Midwest, people were living here, but they were very different than today’s population. This would be close to the boundary (developed in modern times) between the late Woodland period and the late Prehistoric Period when people were building earthwork monuments like Serpent Mound (but we’re 1,000 after the Newark Earthworks). If you’re in Cornwall, you’re looking at Anglo-Saxon England before the Norman invasion with Cnut the Great in the throne. In China, we’re in the Liao Dynasty. The Holy Roman Empire is seeing the end of the longest ruling emperor, Basil II. The world was very different.

What about 10,000 years ago? We’re looking at ~8,000 BCE. That’s about 3,000-4,000 years after the last Ice Age. In parts of the Middle East, this is would be smack in the middle of the Neolithic Period, when stone tools were all the rage and pottery was being developed while Europe was closer to the Paleolithic – that’s the period that goes back to the first use of stone tools! There was likely fewer than 40 million people living on the planet, or roughly the population of Tokyo today. Even mammoths were still around in small pockets across the shrinking post-glacial northern latitudes.

Jump back even further to 100,000 years ago. That might seem like a long time, but that is only 0.002% of the history of our planet. We’re still in the most recent period of the geologic timescale (the Quaternary), but there aren’t any people (well, modern humans) in the Americas. Or Australia. Or most of Europe where you’d run into Neaderthals rather than “modern humans”. The Earth was colder, bouncing between Ice Ages after just getting out of the last “interglacial” warm period about 120,000 years ago.

Earth Before Us

Spin back to 1,000,000 year ago. That’s got to be a long time ago, right? Well, we’re actually still in the Quaternary Period. Sure, our ancestors like homo habilis and homo erectus was showing up in Africa, but we’re still 800,000 years from homo sapiens. The planet is still in its “icehouse” period, with general cooler climates compared to today. All sorts of giant mammals existed across North America, like mastodons, sabre-toothed cats, giant sloths and more. If you showed up in downtown Cleveland, you’d hardly recognize the place … especially considering that the Great Lakes wouldn’t show up until over 985,000 years later.

10,000,000 years? Now we’re in the Neogene. The planet’s climate is likely pretty close to today’s conditions. Our ancestors are deciding that maybe it would be cool to come down from the trees once in a while. North America was dominated by these megafauna, with rhinos and camel-like mammals roaming a Great Plains that looked a lot like African Savanna.

Launching back even further, 100,000,000 years ago, still only 2.2% of the planet’s history, we’d have dinosaurs ruling the planet instead of mammals. Birds have had about 50,000,000 years to evolve since the archaeopteryx, but we’d be dodging triceratops, velociraptors and tyrannosaurs. They’d still all have almost 35 million years to be in charge before the asteroid impacted in what is now the edge of the Gulf of Mexico.

A Billion Is a Lot

Pushing back even more, 1,000,000,000 years ago, you’d like think you were on an alien planet. Earth is teeming with life, but you’d need to bring your microscope to see a lot of it. Multicellular life exists including fungi and maybe lichen, but the first plants and animals as we know it are still hundreds of millions of years in the future. Thankfully, you could breathe the air thanks to all this tiny life adding oxygen to the atmosphere about a billion years before you got there. That far back, what would become Ohio would be somewhere in the southern hemisphere as part of a giant landmass called Rodinia. Still, we’re only about one-quarter of the way back to the start of the planet.

Deep time is a hard thing to handle, much like deep space. Our brains aren’t designed to handle time that transcends one lifetime let alone one species or all species. The processes driving these changes like plate tectonics, (most) climate change and evolution happen on such long horizons of time that we need to unwrap them in a way that has meaning to those of us who don’t dwell in deep time.

Why You Need Deep Time

So, why do you need to think about deep time? Two reasons. First, deep time allows for perspective. The world moves very fast – too fast a lot of the time. Understanding that although many things can change in an instant, not everything can. Second, looking back across the deep time of the planet can create an appreciation of the resilient of life on Earth.

This isn’t to say we shouldn’t be stewards for the planet, especially considering how many humans live here now. If anything, we should look at the Earth’s resilience as an inspiration for our own ability to persevere through our human-focussed “short time”. Yet, deep time is also a reminder than nothing is forever and change is the only thing on which we can be certain. Unless you’re lichen.