What is the geologic time scale?

The Geologic Time Scale

The geologic time scale is a way that scientists work to understand the timespan of our planet based on empirical and fossil-based evidence. This evidence is then used to try and place events in Earth’s history. Many things on our planet, such as the formation of mountains, or the draining of lakes by rivers, take millions of years. The creation of life on earth and the extinction of life on earth has happened many times over. Scientists have documented at least 5 mass extinctions.

 “A Drop in The Bucket” within the Geologic Time Scale

Some of these timespans are really hard to envision. We human beings live what seem like long lives, but in the span of earth and space time, we are but the duration of a rain drop, maybe less. Three or four human generations in length might date us back to the 1800’s. This may seem like a long time, but in geologic time, 200 years is not much time at all. On a stop watch, it might be considered just a few fractions of a second in the scale of “earth-time”.

Scientists have broken up earth’s time into various epochs and eras and periods for us to place events. The diagram below is an interesting one, drawn by the amazing and imaginative artist, Ray Troll.

What is the geologic time scale timeline drawing by Ray Troll

Image Credit: Ray Troll’s creative approach on displaying geologic time is not only super cool, but inspiring. Thanks Ray for helping to bring lessons alive!

Understanding the context of these events and the large, large amounts of time things take can help us appreciate life on earth. Studying the geologic time scale can also help us understand how our impacts, although not seemingly strong, must be placed in the context of these larger time scales. We may not see in 100 years, or even 300 years, the full impacts of our effects. Many processes on earth operate on larger time scales of 500 or thousands of years (although major catastrophic events, such as asteroid impact of super volcano eruption are instantaneous).

Blow Your Mind

It is interesting to note: Something like 1:1000 species actually fossilizes. Let me phrase this again to emphasize: Not 1 in 1000 individuals, but 1 in 1000 species actually end up forming fossils. Thus, there are many species that lived and died on earth not captured at all in our lithographic record of life.

Secondly, as a result of this, a bulk sum of the geologic time scale’s fossil record is blank. We know less than what we know. We are missing huge chapters of life on Earth, as dying and decaying organisms either (a) didn’t exist at that time or (b) the conditions were not right for fossilization. New fossil evidence is discovered all of the time which can greatly change the way we perceive these biological-relationships on earth. By recognizing the vastness of what has come before us, we come to realize how small our place is today.

Our Place Today

Our place in geologic history today is very quite and most truly small. These adjectives are used for a reason!

Modern day homo sapien sapiens have arrived on the scene about 200,000 years ago, according to current scientific evidence (which could change).

Just imagine: it took 800 million years for Earth just to cool from a hot planet to form oceans.

Then another 1500 million years (that’s 1.5 billion) for Earth to go from having cynobacteria (earth’s first bacteria), to stromatolites (earth’s actual first life-multi-stuff) actually forming.

Suddenly then in the last 0.2 million years (that’s 200,000 years ago), the modern human came to be.

1,500 million years for life to aggregate to multi-life. Then 0.2 for human beings. Consider that if those numbers relate to you.

Earth has gone from her continents being broken apart, to having merged into Pangea, and then breaking back apart again to resemble today’s configuration–and then she [earth] developed soft bodied marine organisms, her first vascular plants, gymnosperms (pine and conifer trees), and then was slammed with a mass extinction via a volcano—BOOM–and then rebounded, flourished, with her life into the shapes of dinosaurs, mammals, birds, flowers and eventually in its last ticking seconds, we homo sapiens come walking onto the scene and think we own this whole show?

We are so late to the party, we haven’t taken our shoes off or even gotten appetizers yet.

We Forget the Larger Time Scale of Life

In our modern age of give me this now, and technological-inundation we forget that we are not the mastheads of this planet, nor does she run according to our watch. We’re not holding the stopwatch, mother nature is. We are but a result of many millions and billions of years of processes that set the stage for our arisal, and we’ve barely scraped the surface of time.

Just the oxygen you’re breathing into your body now as you read this sentence came from millions of years of photosynthetic bacteria respirating and oxygenating our oceans enough to saturate it and volatilize into our atmosphere.

Given our short arrival, we’ve made quite a dent in the biosphere thus far, and whether we use this mineral concentration, resource exhaustion, urbanization and technological life to explore space or fizzle out on a dead rock, the choice is up to us. If we confuse these time scales, or our place in the fabric of things, than we risk making a grave psychological error.

Mother earth will live on until the sun takes her life, or until she is zapped by a gamma ray or blasted by an asteroid the size of the moon. She’s been hit by asteroids and super-volcanos and life has been knocked back and forth before and has rebounded.

The question is–will we shoot ourselves in the foot and negate our own success? Or will we find victory through our own awareness and choice?

We are not as concrete or permanent as we think—we are susceptible to instant-death at any moment, just as each of us are within our daily lives, each breath is a gift, while our mother planet will likely carry on.

We ought to use these understandings not to be worked into fear, but to appreciate this place: one another, our planet, the masses of life that has swarmed upon here just to set the stage for us. We are a part of a time scale much larger than ourselves, and it is very likely there will be predecessors to us on planet earth, just as there have all been for all species before us. Of all the life that’s existed on this planet, 99% of it is now extinct – truly we are all the “1%”–everything you see around you is but 1% of the life that earth has seen.

When we look at geologic time, we should see the scale of things and we should see our impermanence.

When we can get a grasp of the “Bigger Picture”, we can get a bit of wisdom if we’re paying attention. We can see ourselves, this planet, our species, in a different context than before.

This new world we are creating, with technology and a changing biosphere – we ultimately must shape where it goes or it will shape us. What sort of place will we choose it to be?

500 years may not seem like much, but if you read this article you’d understand how short that time period really is. It will come and go. How are we changing earth now and in what direction? Can we be aware and consciously direct the movement and integrity of our biosphere? Unless we work to be aware and find solutions, we may never know!

Learn More

Educational Geologic Time Scale iPhone Apps:

If you want to learn more about geologic time and get your “Bigger Picture” and have an iPhone, there are some great educational apps that you can utilize. These are some great tools to really better understand the scales of time that affect our earth:

  • Geo Clock
    This is a nice little app that gives you a sweet and short animation of plate tectonic movement, as well as shows you the time scales of earth.
  • Geotime Enhanced
    This is a cool app that shows the geologic timeline, but also shows specific species information in artistic renders.

Other Websites:

All of these links are pretty cool and can teach you more than I have in this post!