2187: Geologic Time
Title text: Ok, well, we'll be sure to pay you sometime soon, geologically speaking.
Analogies to explain the passage of billions of years are often used in popular science explanations, to help compress these huge spans of time into something the human mind can comprehend; the football field analogy is one such analogy. The Earth is approximately 4.54 billion years old; if you were to present a timeline of Earth as long as a football field (100 yards or 91 meters), then each inch of that length would comprise more than 1.26 million years of Earth's history and each millimeter nearly 50,000 years.
- Complex life refers to the various animal species which arose in the Cambrian explosion 541 million years ago; the length of time that complex life has existed would translate to 11.9 yards on the football field.
- Dinosaurs are estimated to have first evolved as early as 244 million years ago, and survived until the Cretaceous–Paleogene extinction event 66 million years ago; thus it would begin at the 5.37-yard mark and continue up to the 1.45-yard mark.
- Although the evolution of mammals can be dated to around 220 million years ago (depending on definition), they didn't truly become dominant until the aforementioned extinction event paved the way for them to grow and diversify 66 million years ago. The age of mammals therefore extends from the 1.45-yard mark to the goal line (present day).
- Homo sapiens is estimated to be 350,000 years old; our species takes up only a meager 0.28 inches on the football field, or 7.1 millimeters.
- The Holocene era, or the age in which humanity rapidly grew to dominate the Earth, is even less geologically significant, having lasted about 11,650 years so far, which translates about 0.234 millimeters.
- Recorded history begins with accounts dating back to roughly 3500 B.C.E., about 5500 years ago as of this comic's publish date; it would take up a width of about 111 micrometers. A human hair can be as thin as 17 micrometers, or as thick as 181 micrometers, so Megan's claim that all of human history can fit within the width of a human hair depends largely upon the sample being used.
Megan, a geologist, tells a story about how small the timespan of human history is compared to Earth's total history. She does this to juxtapose it with normal human time-scales, to imply that her being two weeks late turning in her project is immaterial by the standards of the Earth's tremendous age. She tries to sell this story to Cueball and Hairbun, but Hairbun's response does not seem to bode well for Megan.
Megan's delay of two weeks would map to three nanometers on the football field. The most powerful electron microscopes have a magnification of ten million, which would make it look like three centimeters (about an inch), so her statement about it being "too small to see even with a powerful microscope" is a bit of an exaggeration. The most powerful optical microscope has 6500x magnification,(New York Times, March 8, 2011) which would indeed be inadequate.
Randall states in the caption that this is a trick that geologists always try to use when being late turning something in.
In the title text, Hairbun and Cueball reply by turning Megan's own argument against her. They promise to pay her for her work in what could be considered a short amount of time on the geological scale - which could easily be many, many times longer than Megan's own lifespan. Megan, like all working people, wants to be paid in a timely manner for her work, and would be deeply dissatisfied to have her payment delayed for so long. Thus, Hairbun and Cueball's rebuttal proves a point: when other people require you be punctual, it's easy to dismiss them as just being impatient; when you're the one who needs other people to be punctual, it's not so easy to criticize yourself.
The comparison with a football field is a typical, but doubtful practice to explain people what the size of an area is (1257: Monster). Here it is used as an analogy with a one-dimensional timescale.
- [Megan, arms spread out, is delivering a long-winded explanation to Hairbun and Cueball.]
- Megan: Imagine Earth's history as a football field, from the planet's formation at one end to today at the other.
- Megan: Complex life would be largely limited to the final ten yards. Dinosaurs appear at the five-yard line, the age of mammals happens in the last 1½ yards, and humans arise in the final few millimeters.
- Megan: All of written history would fit in a strip narrower than a single hair.
- Megan: "Two weeks" would be too small to see even with a powerful microscope.
- Hairbun: Mm hmm.
- [Caption below the panel:]
- Geologists always try this when they're late turning something in.
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