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Narrative Description of Arrow of Time Poster
Regardless of how we look at Nature, we see change. Some of that change is obvious, such as when an earthquake suddenly occurs or when a star explodes as a supernova; other kinds of change are more subtle, such as when continents drift across our planet or when a star like our Sun experiences billions of years of slow and steady fusion. Some scientists give this process of universal change a more elegant name--cosmic evolution. Simply defined, cosmic evolution examines developmental change through time.
The caption for this poster states: "The arrow of time, from the origin of the Universe to the present and beyond, spans several major epochs throughout all of history. Cosmic evolution is the study of the many varied changes in the assembly and composition of energy, matter, and life in the thinning and cooling Universe."
The arrow of time is an archetypical symbol for the construction of order from chaos, of complexity from simplicity, of organic from inorganic matter. From the beginning of the Universe (at left) to the present (at right), change has, over the course of all time and throughout all space, brought forth, successively and successfully, galaxies, stars, planets, and life forms.
This poster depicts seven major construction phases stretching across the entire arrow of time. These include all the major epochs of evolution: particulate, galactic, stellar, planetary, chemical, biological, and cultural. As such, the familiar subject of biological evolution--neo-Darwinism-- becomes just one segment of a much broader evolutionary scheme stretching well beyond mere life on Earth. In effect, what Darwinism does for plants and animals, cosmic evolution attempts to do for all things.
Specifically, in each of the diagonally oriented "windows"
along the arrow, we have:
1. A particle collision in a high-energy accelerator, typifying events
in the aftermath of the big bang, roughly 15 billion years ago.
2. A spiral galaxy, such as those that emerged in the relatively early
Universe, about 10-12 billion years ago.
3. An average star, like our Sun, typical of those that have originated
(and continue to do so) within galaxies.
4. Our planet, the Earth, one of several known balls of heavy-element
gas and rock that accompanied the birth of our Sun some 5 billion years
ago.
5. A scene from a volcano, much like those that perhaps helped to trigger
the origins of life on Earth, a series of events in pre-biology known
as chemical evolution thought to have occurred here some 3.5 billion
years ago.
6. A trilobite, or extinct marine invertebrate, symbolizing one of the
greatest advances in biological evolution, a little less than a billion
years in the past.
7. A symbol of our technolgical society--a telescope, among other "modern"
inventions such as the wheel, clock, piano, and aircraft.
It is the telescope, in fact, that, as a time machine, enables us to look back into our distant past, to study epoch-making events that occurred along earlier parts of the arrow of time--and thus to understand the nature of the Universe before the arrival of sentient human beings. In this sense, cosmic evolution is an attempt to understand who we are, and whence we came.