Whenever I hear myself whining about the rudely curtailed, sheltering-in-place, convalescent life I am forced to lead these days, I remind myself of the odds that I beat, that we all beat, in order to get into this world at all. Odds that make the Powerball jackpot look like a sure thing. Odds that confer an inestimable value on human life under any conditions.

Dr. Francis Collins, director of the project to map the human genome, says that there are 15 characteristics of the physical universe — "constants," he calls them — that have been precisely determined by physicists. These characteristics seem to have been arbitrarily set, and if any one of them were only slightly different, we would not be here.

Take the gravitational constant. If gravity were only slightly weaker than it is, stars could not have coalesced from the primordial cloud of hydrogen. The universe would have remained a shapeless lifeless hydrogen soup. We would not be here.

If gravity were only slightly stronger, the universe would stop expanding, the Big Bang would become the Big Crunch and life would not have had time to form. We would not be here.

"And that's just one of about 15 such constants," says Collins, "all of which, if you tinker with them, result in a universe not capable of sustaining any form of life. I'm not just talking about life like we recognize it, but anything that involves complexity."

There's more. The first generation of stars consisted entirely of hydrogen and helium, with none of the more complex elements, like carbon or oxygen, that are necessary for the development of life. These elements were manufactured in supermassive stars by fusion and supernova explosion, and spewed out into the universe in clouds from which a second generation of "metal-rich" stars formed, including our sun and its surrounding disk of elements from which the planets coalesced.

One of the planets was a rocky little world that formed in the middle of the Goldilocks zone, the range of possible orbits around the sun where temperatures were neither too hot, as they are on hellish Venus, nor too cold, as they are on frozen Mars, for liquid water, essential to life, to exist. Our Earth is a watery world and our bodies are 70% liquid water, and so here we are.

There's more. Early in its history, our still-molten earth collided with a Mars-sized planet. Had the collision been direct, the earth would have been shattered and we would not be here. But it was a glancing blow that knocked the earth's axis 23.5 degrees from the vertical, thus causing the seasons, which are thought to be necessary for the development of complex life.

What's more, the collision knocked loose material from the earth that coalesced into the moon, virtually a twin planet that has acted like a pendulum to our earth, stabilizing it on its axis and preventing the kind of tumbling that has afflicted our rocky neighbors and that would produce radical climate changes, making the development of complex life unlikely. Finally, the influence of the moon has encouraged human reproduction, or so many poets have informed us. And so, here we are.

There's more. For 3 billion years, the life that arose for reasons not clearly understood on this rocky planet took the form of single-celled organisms, bacteria and algae. And then, for reasons not understood, complex multicellular life appeared, plants and then animals, in the sea and then on the land, covering the earth and filling the seas over the course of 500 million years.

For tens of millions of years, much of the complex life that developed on our rocky watery little world took the form of giant, ferocious meat-eating predators, and our distant mammalian ancestors were small furtive shrew-like creatures cowering in the shadows, a negligible set of species unlikely ever to amount to anything. The dinosaurs were so good at surviving and multiplying and filling Darwinian niches that there seemed to be no end to their rule, or to our ancestors' cowering in the shadows.

But then one day, 65 million years ago, a 6-mile-wide asteroid collided with the earth. Had this rock landed in the oceans that covered most of the planet, the resulting watery disorders would have been great but would probably not have killed all the dinosaurs. But it struck on land, so that the trillions of tons of rocky dusty debris it spewed into space scorched the earth on its meteoric re-entry and shrouded the globe for years after the impact.

Scorched and then deprived of sunlight, the plants died, the plant-eating dinosaurs died, the predatory eaters of the plant-eaters died, the furtive shrews emerged from the shadows to inherit the earth. They multiplied and diversified, producing in the course of tens of millions of years homo sapiens, a species of hairless primates who because of their physical defenselessness and large brains learned to use tools and thus came to dominate the planet.

Twelve thousand years ago, at the end of the last ice age and for reasons that are not clearly understood, humans began to abandon their nomadic hunter-gatherer ways, to settle down, to practice agriculture, to domesticate animals, to live in villages, and then, in the river valleys where cooperation was necessary, to build cities, to organize countries, empires, civilizations. These civilizations spread from the river valleys to cover the world.

One of these civilizations, in a backwater called Europe, developed a scientific technology that produced a population surplus and the mechanized means to ship it elsewhere. In geological time just a few fractions of a second ago, in human time 170 years ago, a farmer in Norway decided to emigrate across a wide ocean. He settled in a region called Minnesota, resumed farming and had many children and grandchildren. At the same time, a carpenter in Dublin, Ireland, decided to cross the ocean and make a new life in a new land. He settled in a region called Iowa, and had many children and grandchildren, some of whom went to work for the railroad.

In 1940, the great-grandson of the Norwegian immigrant farmer was a soon-to-be college graduate looking forward to graduate study in history at the University of Minnesota. The great-great-granddaughter of the Dublin carpenter, daughter of a railroad station agent and a recent high school graduate, had left her home in a small Iowa town to stay with an ailing aunt in New Jersey. The chances that these two social atoms would ever meet were extremely remote.

At his mother's request, the young man deferred his graduate study for two years and took a teaching job in a small Iowa town so he could send money to his brother, a medical student. The young woman returned home from New Jersey to that same small town. They met, they fell in love. But she was Catholic and he was Lutheran. Interdenominational marriages were difficult, if not impossible. Impasse.

Then the Japanese attacked Pearl Harbor. The nation was at war. The young man enlisted in the Army Air Corps., was soon to be shipped out. If they were to have any life together, it must be soon. Against her family's wishes, the young woman traveled to New Jersey, where the young man was stationed, married him in a civil ceremony, spent a single night with her husband amid weeks of separation, past and future.

The chances that a healthy egg would be waiting on that night were, let us say, one in four; the chance that the child born nearly nine months later is the person he is and not someone quite different is as steep as the father's sperm cells are numerous, several hundred million to one; again, greater than Powerball jackpot odds.

Yet, against multiple great odds going back to the Big Bang itself, a billion billion-to-one shots, here I am. Me, myself and no one else.

The gift of life. Use it well.

Michael Nesset lives in North St. Paul.