For now, a followup to my idea to carry a trilobite fossil everywhere. I did some research.
717 years ago the modern era began in the West. I date it to 1277 when a papal bull was issued, declaring that anyone who sought to find regularities in God's handiwork (what we would now call Natural Laws) was a heretic, because they were implicitly denying God's ability to act on His whim. This bull was a bust, because before the bull, only a handful of guys at the Sorbonne had a clear idea of this Natural Law thing and where or how it differed from the teachings of the church. After the pope spelled it out so clearly, the idea was here to stay. Oops. Of course, the Sorbonne itself was an expression of the 13th century cultural fluorescence which produced the Middle Ages, so we can say ~800 years. Western culture has existed for ~800 years.
2300 years ago -- 3 times as long ago as our Western Culture has existed -- Alexander of Macedon conquered the known world. (Using his father's army, tactics, treasury, maps, and plans, be it noted.)
4200 years ago -- almost as long before Alexander as Alexander is before us -- Sargon of Akkad conquered the known world, the first person in history to do so. There wasn't so much to conquer, but his empire, the first Empire, stretched from the Mediterranean to the Red Sea.
5500 years ago -- 1300 years before Sargon (from the fall of Rome until today) writing was invented.
7500 years ago cities were invented. People lived in cities for 2000 years before writing was invented, and for 3000 years before Sargon established the first Empire.
12,000 years ago agriculture was invented. Agriculture existed for 4500 years before there were cities -- as long as the time from Sargon to us. Alexander could remember the invention of agriculture as distantly as we would remember him if the same distance lay between us then as now, and we were founding the first city.
Homo sapiens has existed for 250,000 years, and spent 20 times the amount of time we have with agriculture chasing reindeer and making cave paintings and so forth.
Fire has been used by hominids for 500,000 years. Homo erectus and that lot were using fire before we existed at all for as long a period of time as we have existed.
Hominids have existed for 2,000,000 years. 1.5 mil without fire. Primates for 4,000,000 years. Mammals for ~40,000,000. Vertebrates have existed for 220,000,000 years. Multicellular organisms for 540,000,000. Eukaryotic organisms for 1,400,000,000 years. Life itself for 3,500,000,000 years.
The earth is 4,500,000,000 years old. For a billion years there was nothing, then for 2 billion years there was nothing but bacteria, and then for a billion years we had bacteria + algae, and then finally the exciting half-billion years of multicellular organisms.
Just to catch up, that means that for as long a period of time as there have been multicellular organisms, there was nothing more complex than algae, and for as half again as long a period of time as there has been algae, there was nothing but bacteria. There have been multicellular organisms for 100 times as long as anybody has been using fire, which itself is twice as long as homo sapiens has existed.
That trilobite fossil you can get for a couple of bucks at a rock shop and carry around with you in order to remind you what's important and what's not was among the earliest multicellular organisms. They all went extinct 250,000,000 years ago, so any such fossil is no less that one quarter billion years old and maybe as much as half a billion years old, when it was a bug crawling around under water.
Tom Price firstname.lastname@example.org
snarl-headed curs fell to a-kicking and cursing of me