over 13 billion years to reach us. The distance from Earth adds up to about 100,000,000,000,000,000,000,000 miles. Lightman questions whether we as human beings can actually comprehend such enormous expanses of distance and time. “Science has vastly expanded the scale of our cosmos,” he writes, “but our emotional reality is still limited by what we can touch with our bodies in the time span of our lives.” He wonders whether Illingworth and other astronomers can feel connected to this huge cosmic terrain: “Or are such things instead digitized abstractions, silent and untouchable, akin to us only in their makeup of atoms and molecules?” In other words, can we only comprehend and feel we are a part of the same reality with the cosmos when we reduce it all through physics to basic particles?
Lightman quantifies our existence within the cosmos in another way, a way that makes us seem like a random, insignificant detail in the general cosmological scheme of things: the totality of living matter on Earth—everything
from human beings to the scum floating on a pond—accounts for 0.00000001 percent of the amount of the mass of the planet, and based on the best research we have at the moment for the potential for life-sustaining environments elsewhere in the universe, that number for living matter in the universe amounts to 0.000000000000001 percent of the mass of the universe. A very small number indeed. Beyond insignificant in fact. Yet such reductionism doesn’t actually help our understanding of our place in the cosmos.
It’s more relevant, Lightman implies, to look at our personal experience. The physicist both begins and ends his essay remembering an experience he once had of “infinity” when he was sailing on the Aegean Sea. He and his wife found themselves in a place where they could look fully around themselves and see neither land nor any other boats. Just water and sky. It was then that he realized some sense of infinity: “a sensation I had not experienced before, accompanied by feelings of awe, fear, sublimity, disorientation, alienation, and disbelief.” And with that moment of insight he understood more about what it means to be human in this vast universe than all the numbers and digital images of far away galaxies could ever convey to him. So perhaps we can only be truly at home in the universe, not by intellectualizing it or analyzing it, but just by settling right in and fully experiencing it.