USA Today

In the Blink of a Simile

Science writers are clever.

Whenever they want to impress upon a reader that a very long period of time is not so long in a geological context, they break out the inevitable blink-of-an-eye simile.

For example, when the Christian Science Monitor reported in a June 4 article that whales took only 5 million years to evolve, they quoted one researcher as saying:

Five million years is like the blink of an eye.

National Public Radio’s Andrea Seabrook made a similar assertion in a 2008 segment of Science out of the Box when she stated that the Holocene epoch

…began 12,000 years ago, a mere blink of the eye in geologic time.

And a story in USA Today from 2004 about volcanic eruptions in the Pacific Northwest of the US said:

…Rainier hasn’t blown big-time in 500 years — hardly a blink of an eye in geologic time.

Finally, Time Magazine, in a 2008 piece about climate change wrote:

In less than a human lifetime — barely the blink of an eye in geologic time — a way of life millenniums old will be lost here.

The simile by itself is just a conventional illustration of proportion. But taking the above examples together with all their discrepancies, one is left with a disturbing question.

Why can’t science writers blink like the rest of us?

One theory is that science writers are aliens from another solar system and thus have no eyelids. They have travelled great distances in space and time to come to this planet and write for USA Today. This would explain why these writers know so much about everything, but are woefully ignorant about blinking.

But that’s just one stupid theory for one of my more inane pet peeves. I’ve lost sleep wondering how much a blink of an eye really is in geologic time. Is it five million years? 12,000? 78?

The answer, as it turns out, is none of these.

Here’s why: Assuming the Earth is 4.5 billion years old, and the average life expectancy of a white man in New Zealand is 78 years (rounding down), then one year in geologic time is 1/78 of 4.5 billion, or 58.2 million years. A geologic month, then, is 1/12 of 58.2 million years, or 4.8 million years; and so on, subdividing time in like fashion down to .4 seconds, the average duration of a human blink.

Here, then, is a proper use of the blink-of-an-eye simile:

Woman-in-Labor: Finally. I thought this baby would never come out.

Helpful Physician: Ma’am, you might think nine-and-a-half months is a long time to be carrying around a baby, but it’s only a blink of the eye in geologic time. So get over yourself.

Now, applying my scale to some of the aforementioned stories, I come up with better and more accurate similes. For example:

In less than a human lifetime — roughly six blinks of a normal, non-catotonic human’s eye in geologic time — a way of life millenniums old will be lost here.

Here’s another one:

The Holocene epoch began 12,000 years ago, a mere feature-length movie called Bring it On starring Eliza Dushku in geologic time.

And finally:

Five million years is like the amount of time it took for my anti-psychotic meds to finally kick-in in geologic time.

Yes, unfortunately this is what I spend much of my time thinking about.