Oh, How Times Have Changed

By Michael Hawkins

In all my attempts to explain certain things about science, I’ve noticed something: a lot of people just don’t know the general timeline of significant events. These are important things to know, if only so one can at least have a general idea of what’s going on whenever science is discussed. Even more to the point, I would have to imagine a lot of people care where their money is spent. In Europe, for instance, one of the largest scientific collaborations amongst nations, the Large Hadron Collider, has a budget of roughly 9 billion dollars. Most of that is not American money, but regardless, the people who are paying for it ought to know that it is entirely predicated on the notion that the Universe emerged from the Big Bang roughly 13.7 billion years ago. If someone believes instead that the Universe is, say, 6,000 years old, then there is clearly an issue. The predication on which the Large Hadron Collider stands doesn’t make much sense for that person.

So it is with that in mind that I present my own attempt to knock down that sort of ignorance, or at least give a refresher. “BYA” stands for “billion years ago”, with the substitute “M” meaning “million”, and “T” standing in for “thousand”.

13.7 bya – Big Bang
13.0 bya – First galaxies form
10.0 bya – Milky Way forms
4.6 bya – The Sun forms
4.5 bya – Earth forms
3.9 bya – First life appears
3.0 bya – Photosynthesis appears
2.1 bya – Eukaryotic cells appear (you are a eukaryote)
1.0 bya – Multicellular life appears
580 mya – Cambrian explosion, tons of complex arms races evolve
400 mya – Tetrapods evolve
360 mya – Amphibians evolve
230 mya – Dinosaurs evolve
200 mya – Mammals evolve
150 mya – Birds evolve (we would have called them dinosaurs at the time)
65 mya – Big ol’ asteroid. Dinosaurs that can’t fly die out
50 mya – With T-Rex et al gone, mammals diversify
5-7 mya – Great apes, monkeys split (humans are great apes)
2.6 mya – Earliest tool use detected
150 tya – First anatomically apparent humans emerge
30 tya – Last Neanderthals die
15 tya – Wolves domesticated as dogs
11 tya – End of last ice age
5 tya – First preserved written language
3 tya – Egyptians build pyramids. Also praise cats.
476 AD – Fall of Rome
1643 – Newton is born
1743 – Thomas Jefferson is born
1809 – Charles Darwin and Abraham Lincoln are born (same day)
1999 – Mystery Science Theater 3000 is cancelled
2009 – See evening news

So there you have it. A basic sketch of what has happened over the past 13.7 billion years. While most events, such as the extinction of the dinosaurs 65 million years ago, don’t tend to be as hurtful as the cancellation of Mystery Science Theater 3000, they are all important.

Finally, the point of the time line I want to really take a moment to point out is with the evolution of humans. The split between us and other modern apes occurred roughly 5-7 million years ago. Emphasis on “other”. There is no taxonomic grouping that separates humans and, say, orangutans on the Family level. Humans, orangutans, gorillas, and chimpanzees are all Great Apes. Further included in that grouping would be a massive number of extinct species, many of which would resemble early humans in a number of ways. (And by “early”, I mean humans from just 50,000-100,000 years ago.) We are apes, which are first primates which are first mammals which are first vertebrates which are first animals which are first eukaryotes which are first simple replicators which are first the stuff of stars.