Let’s put things into perspective. It’s important to realize that regardless of how wound up we become in our individual lives, in our hopes, dreams, struggles and concerns, we take place in a much larger picture that determines most of our lives. Our families, our nations, our cultures and civilizations – there is a large background to everything we do that is often obscured, blocked out by our narrowly evolved attention and limited focus. In a society of millions, in a culture of tens of millions, in a civilization of hundreds of millions and a world of billions, we live out our lives in relative ignorance of most of what goes on. This article attempts to give some context to just how, well, big, everything is compared to one of us.
Our place in Time
Humans, in good condition, can live to be around 80 to 90 years – that’s roughly 30,000 days. Presently there are 7 billion other people walking around the planet, and since we all experience time at the same rate, that’s 7 billion human-days per day. Each day on Earth represents 230,000 human life times in terms of raw human experience, therefore even if you live to be 85 years old you’ll hardly experience a millionth of a percent of what goes on among humans on Earth in a single day. This is just current events; things get bigger if we look backwards.
50,000 years ago lived a couple from whom the entire human race descended (we know this through Mitochondrial DNA – google it). Since then, in all of our history there have been 107 billion humans that have walked this Earth. That means right now, only 7.5% of the human population is alive. How many days have been lived over the course of history? Naturally this depends on the size of the population and life expectancy, which both change over time, but using a weighted mean we can figure out that since our Mitochondrial Adam and Eve there have been just shy of 6 trillion years of human life lived, or about 20 years of human life for each star in the Milky Way Galaxy. In our 85 year life span, we experience seven trillionths of a percent of all of human history. And you thought you could keep up with things on twitter. Looking beyond the Earth is even more humbling, or depressing, depending on your outlook.
The Universe began 13.7 billion years ago, which means us humans as individuals have lived, in aggregate, over 400 times longer than the Universe we inhabit. If we imagine the whole history of that time as a single calendar year, splitting those 13.7 billion years into 12 months so that the Big Bang is at 12:00am, January 1st, and the present is midnight, December 31st, where do we come along? On this timeline, the Milky Way Galaxy forms around May 11th, and our own Sun first starts shining in the beginning of September. By October the Earth is teeming with photosynthetic life, but its not until December 14th that we see simple animals arise. Us humans have to wait until December 31st, 2:00pm, before we come on the scene. When does our recorded history start, wherein began every tradition, invention, poem, and story that make up the roots of our cultures? 15 seconds to midnight, December 31st. All of the Enlightenment, modern science and technology, human rights and democracies, everything that defines the present-day world began at 23:59:59, 1 second to midnight. Our time as individuals is utterly dwarfed by both the past that has come before us, and the magnitude of the activity around us. We cannot hope to experience it all, so spend your time wisely.
Space is a different story. Accessing space is much more difficult than time: we have the benefit of travelling through time even when we’re standing still, which means we can cover a good distance by not moving. To travel through space you need to move, however the faster you travel through space the less you travel through time. The conversion factor between space and time, or the “exchange rate”, is the speed of light: if a person travels at that speed through space their travel through time stops completely; likewise if they stand still they travel through time at the speed of light (also called “C” for celeritas, the latin word for swiftness). Space, and time, are both measurable by the same quantity, C, and our travel through either can never exceed C.
In practice, the space we can access is largely 2-dimensional. We live on the surface of a planet, not in the sky or in the sea, in which case our living space would be much more 3 dimensional. Yes, we can walk up stairs or on to a plane, however our range of movement is confined to flat surfaces that we can stand, walk, or maybe jump on. Intuitively this sounds odd, but of all the volume of Earth (all 3 x 1024 m3 of it), the most we can access by running around the surface is a spherical shell extending from the ground to however high you can reach, probably not much more than 2 meters (a volume of 1 x 1015 m3 for comparison). In other words, as surface-crawling creatures we can access about a billionth of the volume that counts as our planet, atmosphere and all.
Some might argue we don’t need to be someplace to access it. We can use a video camera, or microphone, or long stick to get the sensory experience of a remote location. In that case, the range of space we can access is limited by how fast we can send electronic signals, which of course travel at C. If we want to experience relevant events, i.e. events that occurred while we are alive, we couldn’t receive signals from a distance further than our lifespan in light years If we live to be 85 years old and get a signal that originated 90 light years away, that signal was sent 5 years before our birth. Our “accessible space” volume is now a sphere with radius of 85 light years. How does that compare with what’s out there? Of the 400 billion stars in the Galaxy about 70 are within our life-time accessible sphere, which is ten millionths of the total. With a radius of 46 billion light years, the fraction of the universe we ever experience is comparable to the size of a proton relative to a light year. In other words, the space we can hope to reach is utterly insignificant compared to the total there is.
Some may come away from these numbers a bit depressed, others, a bit amazed. In our efforts to stay connected, be informed, up-to date, well travelled or well-read, we are always comparing ourselves to our peers and what we think of as the potential out there. Keep in mind that no matter what you do, it is only the barest fraction of a percent of all there is. We are far better off focusing on making meaningful lives as individuals, and cultivating experiences that are rich and of high quality, than trying to be the greatest, do the most, see everything, or be everywhere at once. It is simply impossible, and once begun the process of comparing ourselves can only lead to disappointment and dissatisfaction.