Our Place in Time

“The only reason for time is so that everything doesn't happen at once.”

~ Albert Einstein

Consider a measuring tape, one of those soft cloth yellow ones used in tailor shops—perhaps a tailor shop in Boston. If this measuring tape represented time, instead of distance, perhaps we might decide one inch equals a century—100 years. For most of us, if we’re lucky, our lives will span somewhere between three quarters of an inch and an inch. Make a mark, anywhere on the tape, to indicate today.

Looking back in time on our timeline measuring tape, the American Civil War, 1861 – 1865, occupies a tiny sliver of an inch, about one-and-a-half inches left of our mark. The Declaration of Independence was signed in the summer of 1776, about two-and-one-third inches to the left of our mark. Columbus landed on Hispaniola in 1492, a little over five inches to the left of our mark.

Christ lived 20 inches left of our mark. The Battle of Thermopylae, in the fall of 480 BC, in which a small Greek force, led by Leonidas and his 300 Spartans, confronted the invading Persian army, took place about 25 inches, just over two feet, left of our mark.

Stonehenge was built on the southern plains of England in about 3000 BC, about four feet to the left of our mark. The first written records of history began being kept about 3700 BC, or four-and-three-quarters feet left of our mark, about the same time the last woolly mammoth died.

Mesopotamian civilization arose and flourished during the period 8000 BC – 7000 BC, seven to eight feet left of our mark. About this same time, the last saber-toothed cat became extinct. Ten feet left of our mark, the last Ice Age ended. Twelve feet left of our mark, what is now the Sahara Desert was moist and fertile. The earliest permanent human settlement (in what is now the Czech Republic) was established about 23,000 BC, about 19 feet left of our mark.

Anatomically-modern Homo Sapiens first appeared in Africa about 120,000 years ago, or 100 feet (six feet longer than an NBA basketball court) left of our mark. Homo Sapiens and Homo Erectus diverged on the evolutionary chart about 250 feet left of our mark (Homo Erectus had colonized what is now modern Eurasia about 416 feet left of our mark).

Somewhere between 660 and 1300 feet (two to four football fields) left of our mark, Homo Erectus first learned how to control and use fire.

The genus Homo first emerged 2.5 million years ago, approximately 2100 feet, or about four tenths of a mile, left of our mark. The Hominid family emerged somewhere between 12 and 18 million years ago, or between two and three miles left of our mark.

The first grasses emerged on our planet about three miles left of present day. The first elephants appeared about four miles left of our mark. Cats began evolving almost five-and-a-half miles to the left, and canines at about six-and-a-third miles. Seven-and-three-quarter miles left, whales returned to the Earth’s oceans from land. Nine-and-a-half miles left, primates began evolving. Our timeline tape is still within the greater Boston metro area.

The last dinosaurs became extinct 65 million years ago, a little over 10 miles to the left of our mark. The Himalayas began to reach for the sky at about the same time, as the Indian subcontinent began its tectonic collision with Asia’s underbelly. The first mammals debuted about 31 miles left of today on our timeline tape. The age of the dinosaurs began about 250 million years ago, almost 40 miles to the left of our mark, or a few miles west of Worcester.

The first lunged organisms emerged about 420 million years ago, or about 66 miles to our left. The original vertebrates emerged about 85 miles left of our mark. The first complex, multi-celled life forms appeared about 600 million years ago, or 95 miles left. The very first life on Earth likely appeared somewhere in the range of 600 to 650 miles left of our mark. If our present day is in Boston, and each inch represents a century, life began somewhere around Cleveland (I hope no one from there interprets these words out of context!).

Our planet, Earth, formed about 4.5 billion years ago, or about 710 miles to the left. Our Solar System coalesced about 730 miles left of our mark. Scientific consensus suggests the universe began with The Big Bang around 13.5 billion years ago, or about 2150 miles left of our mark—or roughly the distance between Boston and Billings, Montana.

Getting back to the mark on our (extremely long) measuring tape in Boston, what about the part of the tape to the right—our future? What lies ahead? There seems to be a growing consensus among astronomers—particularly among specialists in stellar evolution—that our Sun will continue to get brighter, more intense (as it has for its first 4.5 billion years). Some scientists project that a billion years from now, our Sun will be 10 percent brighter. Our oceans will boil away and, at some point, far out to the right along our measuring tape, our Earth will no longer be capable of hosting life as we know it. At perhaps 5.5 billion years, our Sun will run out of fuel in its core. As it begins to burn hydrogen in the surrounding layers, our Sun will expand into a red giant. Somewhere around 7.5 billion years hence, our long-since dead planet Earth will vaporize as it spirals into our engorged, red Sun.

This future sounds bleak. Keep in mind, however, Homo Sapiens have only been around for about 120 thousand years, or about 100 feet of our measuring tape—just a bit longer than the Boston Celtics’ home court. We didn’t even begin recording our history until less than five feet ago. Even if our Earth only supports life for another 500 million years, that doomsday is still farther into our future than the advent of lunged creatures is into our past. 500 million years is about 80 miles to the right of our mark, a nice drive up the coast to near Portland, Maine. A lot will happen on that journey.