In "A Short History of Nearly Everything," Bill Bryson presents the idea that the vast majority of the Earth's habitable space is unavailable to human exploration and habitation. According to an estimate, over 99.5 percent of this space is essentially inaccessible, highlighting our limited reach in the grand scheme of the planet's geography and ecosystems.

This statistic underscores the vastness and complexity of the natural world, suggesting that even though we may occupy a small portion of habitable space, the intricate dynamics, life forms, and environments that exist beyond our immediate grasp remain largely mysterious and uncharted. Bryson encourages readers to appreciate the wonders of the world while acknowledging the limits of human exploration.