To help the reader realize just how perilous Earth’s orbit actually is, Bryson leverages the metaphor of a freeway to represent Earth’s orbit. Bryson describes the perpetual threat of meteors colliding with Earth and rendering life as we know it extinct, which is what happened to the dinosaurs 65 million years ago. He illustrates this idea through the symbol of Earth as the only vehicle on a freeway—a vehicle that’s zooming along at breakneck speed. At the same time, there are many careless pedestrians who step into the freeway without looking for oncoming traffic. The pedestrians represent the hundreds of thousands, if not millions, of asteroids that regularly cross Earth’s orbit. The metaphor thus helps the reader realize that every single day, Earth happens to dodge all these obstacles completely by chance. It also helps the reader see that although it’s hard to perceive from our perspective, Earth is moving through space extremely quickly—at 66,000 miles per hour, to be exact, which explains why a collision with even a small asteroid would have such a damaging impact.
Freeway Quotes in A Short History of Nearly Everything
Think of Earth’s orbit as a kind of freeway on which we are the only vehicle, but which is regularly crossed by pedestrians who don’t know enough to look before stepping off the curb. At least 90 percent of these pedestrians are quite unknown to us. […] All we know is that at some point, at uncertain levels, they trundle across the road down which we are cruising at sixty-six thousand miles per hour. […] The number of these relative tiddlers in Earth crossing orbits is almost certainly in the hundreds of thousands and possibly in the millions, and they are nearly impossible to track.
Freeway Symbol Timeline in A Short History of Nearly Everything
