There have recently been some thoughtful diaries [here and here] on the nature of people, things and the universe and whether our collective time here on Earth is limited. I feel our time here could be unlimited but for the fact that most people act like unthinking organisms in that they continue to increase in numbers and increase the quantity of things they consume. Obviously, if that trend continues and if we do not escape the planet our time here is limited. Its simple physics, or even just accounting. One of the reasons I've thought that people continue to act as if they are not part of the universe and can continue to act as if we are not subject to the greater laws of the universe is that too few people understand the nature of time. An understanding of the nature of time and of our place in time, I believe, necessarily leads people to rethink their actions. It had that effect on me, anyway. I would therefore propose that an appreciation of TIME become a central part of every school child's education so that children everywhere would know how and why they are each inseparable from the greater Universe. We are of it, and this is what I would teach them.
When I say we are of it I mean we are inseparable from it, that we are just as ancient and profound as the universe itself is ancient and profound and that each of us while individually new to the world contains all those elements of the old, old universe that make it miraculous. The universe is filled with wondrous things and we are one of them.
One of the more wondrous of things is the full Moon in the night sky. Moreover, if you look up on a clear night out in the country there is essentially no limit to how far you can see beyond the full Moon because you can see far beyond your capacity to physically appreciate how far you can see. The "Real" World appears to extend forever in all directions, and the Moon is but a stone’s throw away.
The universe may even be much bigger than we can know. There are some who think it extends forever in directions we can’t see, directions we cannot even think of or about because our minds are not built to see or think about them. Directions that define other dimensions. . .
Even if there are no other dimensions, though, the world we can see is immense and ancient. I realized an analogy was necessary to me when I was trying to understand evolution within this context. I first thought about evolution seriously many years ago while a graduate student studying geology. It was while doing this that I began to appreciate the span of time over which life has left a record in the rocks under our feet. I needed an analogy so I came up with this.
The earth is approximately 4 billion years old, and the record of life on earth stretches back nearly that far. The fossil record of greatest interest to most people is the fossil record of animals and by animals I mean creatures of appreciable size that can be picked up and inspected. This fossil record can be traced back approximately half a billion years, (that is 500,000,000) but just what does that mean? Simply saying these numbers is an insufficient stimulus for inducing an understanding of them because an understanding of something new requires a relation back to something already known. One way to express a distance in time, therefore, is to relate it to a distance in space. This is something with which everyone is already familiar - a timeline.
To establish a timeline describing the duration of the Age of Animals on Earth consider the distance of two feet and eight inches, or 32 inches. If you hold your arms outstretched, with the palms toward each other, and place each hand about eight to ten inches outside its respective shoulder, you will be marking off a span of about 32 inches.
Consider this distance to be analogous to one year composed of the last 12 months. Each month will therefore be represented by about 2 2/3 inches and each day will cover just under a tenth of an inch. Then, measuring directly away from yourself, everyone under 30 years of age will have been born within 80 feet and everyone under 50 years of age will have been born within about 150 feet. The maximum time any of us can have on this earth, so far anyway, is around 120 years. Everyone under the age of 120 will have been born within approximately 100 meters of where you are standing. This distance is not much greater than the length of a football pitch. That short distance, a football pitch with a day equal to just under one-tenth of an inch, on the timeline I am describing, encompasses the lifetime of everyone now alive,
The calendar we use starts 2000 years ago, which converts to a mile (or 1.6 km), and a mile is a distance many people can cover in six or seven minutes on foot. Agriculture dates back 10,000 years, or about 5 miles, which is a pleasant walk of two hours or so, or ten minutes in a car moving 30 miles per hour (or 50 kph). The origin of our species supposedly dates about 2.5 million years, which takes us out about 1260 miles (~2100 km). This is the distance in a straight line (out over the Atlantic Ocean) between Miami and Boston, or between Phoenix and Kansas City, or between Moscow and the Adriatic, or Tokyo and Beijing, and so on. The time of the dinosaurs ended about 65 million years ago which would be two and one-third times around the earth at the equator, if one year equals 32 inches.
To understand when animals of appreciable size first appeared on earth, have this time scale in mind - one day is just under a tenth of an inch, all people currently living were born within 100 meters, and the last 2000 years of history is a mile - the next time you gaze up through a clear night's air at the Moon overhead. That gulf between you and the Moon is how far back in time you have to cast your imagination in an attempt to understand the passage of 500 million years. This is how long complex organisms have lived on Earth. The length of the history of complex organisms on Earth can thus be measured with the same yardstick that we use to measure the age of the whole Universe.
Gazing into the depths of time is also the same as gazing into the depths of space. Both are endless, and we are of this endlessness. We have emerged out of it. Friedrich Nietzsche said "If you gaze long into an abyss, the abyss will gaze back into you." I’ve never been sure what he meant by that, but when I’ve looked at the stars through a powerful pair of binoculars long enough, I start to get a feeling of what I would have meant had I said it.
But, there is no qualitative difference between one day and a million years, it is all duration, and the nature of duration is unchanging. It just is. But what is important is the content of the time, the events it enfolds. A duration as long as the history of the Earth is large enough that it enfolds a remarkable fact about Earth that never seems sufficiently appreciated. During its history, the Earth that you can see out your window has been many different planets. [I tried to explain what I mean in a comment the other day, and it bears repeating here.]
I do not mean literally that the Earth has been different planets. I mean that its appearance, the arrangement and nature of the continents, the size of the continents, the number and types of different forms of life, and the planetary climate have all changed drastically over the course of the eons since animals first appeared. It would have appeared to be a different planet to a visitor, if he or she could have visited Earth at widely separated times during all those different eons.
There have been times when the Earth had only one vast continent, and an even vaster ocean over which you could have sailed for thousands, and thousands, and thousands of miles without sighting land. At other times it has had smaller, numerous continents spread over the surface. There have been long eons of geologic and climatic serenity. In these more peaceful times life has flourished in riotous variety and intensity. There have been other times when the surface of the Earth was ripped from underneath by the sudden eruption of cubic miles of lava that poisoned the air with noxious gases. It has been blasted from space by meteors whose impacts have boiled the ocean, cracked the crust, and killed nearly everything. It has been populated repeatedly with immense herds of large animals, innumerable deadly carnivores, forests stretching thousands upon thousands of miles, and deserts that today would encompass whole, and large, continents.
The Earth has had many climates. It has been a hot, blasted wasteland, and it has been a frozen ball where once nearly the entire planet was covered in thousands of feet of slowly flowing cold, blue ice. It has been a garden of Eden, with verdant forests and azure seas stretching around the globe, a place where unknown millions of forms of life have arisen, lived for eon after eon after eon, and then perished. Many left no trace. Over that gulf of time, the Earth has been many things, and it has been each of those many things for millions of years at a time. All of Earth's surface attributes, patterns, and life forms have arisen, shifted, developed, ebbed and flowed. It is well worth noting that creatures like us, and by that I mean creatures that possessed intricate, vertebrate brains, have endured over a large portion of that immense span of time.
We are therefore part and parcel of the most ancient orders of the universe. We are possessed of and express attributes that have arisen out of the depths of time and the unending reaches of space. Einstein once said "There are two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle." My understanding of the history of the Earth has left me with only one of these choices. I’m not religious in the normal sense by any means and I sometimes have a difficult time dealing with people who are, but I’ve come to appreciate that the Universe and the Earth and all creatures, us included, are indivisible parts of a much greater and miraculous whole.
I’ve said too much already as I tend to run off at the keyboard, but in closing I have to say that I cannot help but think that if children are better taught to appreciate their true place in the observable Universe, that better behavior will result and that maybe that would contribute to us not becoming extinct.