Editor and General Manager
Please sit down. Are you sitting? Okay, question: How fast are you going? Answer: About 66,000 miles an hour. Pretty fast, huh? And, if you happen to be near the equator, the screaming-fast planet you’re traveling on is spinning at about 1000 miles an hour.
Some other fun facts: the Earth is approximately 150 million kilometers from the sun, which is so big we can see it with the unaided eye. Its rotation exposes the entire planet to light and dark periods in turn every 24 hours. Plus, wobbling on the axis provides a gradual back-and-forth tilt, so that the further reaches of the Northern and Southern hemispheres get to enjoy what we happily call the four seasons.
While we fly through space we have a partner, the moon, a planet-like body one-quarter the size of Earth that travels with us. An atmosphere surrounds the Earth, and its gases help trap just the right amount of heat for the planet and include all-important oxygen. Seventy percent of the planet is water—right up there with oxygen in importance—and, amazingly, this does not leak off the bottom of the planet. This is because of gravity, which I know exists because of the physical evidence, but whose explanation is beyond my grasp. Gravity keeps the moon nearby too. And the universe together. I think.
The Milky Way, the galaxy where we live, is itself barreling through the cosmos and contains between 200 and 400 billion stars, maybe more, and at least 100 million planets, spread out over, roughly speaking, 100 million light-years (really big). It is currently estimated that there are between 100 and 200 billion galaxies, each of them chock-full of stars and planets.
As many as 50 billion species have inhabited the planet at one time or another, and more than 99% of those are gone forever. The millions of species that remain today—including humans, you in that chair and me in mine—are a statistical fluke. In the 4.5 billion years since the planet was formed there have been at least 20 periods of extinction, in which a
large amount of the planet’s life disappeared. (Most extinctions take place over long periods of time as a response to environmental changes, and not in grand cataclysmic events.) The causes, when known, are varied, and sometimes multiple. There have been five mass extinctions, in which upwards of 75% or more of existing species disappeared forever. Many scientists believe that the planet is in the throes of an extinction event at this moment, known as the Holocene, and attribute it to the climactic changes resulting primarily from the burning of fossil fuels.
So, what does all this mean? Where does that leave us, besides holding onto our seats? First, it would seem that whatever creation story you might favor, it is clear that we do not inhabit a garden designed just for humans—one that has our needs in mind, one in which we can romp and exploit at will and without consequence. No, we’re just the wrong side of a Holocene event away from becoming just another fossil. Should we disappear, the trillions of stars and planets and billions of galaxies out there will not notice.
We won’t live on another planet anytime soon. It takes seven months to get to Mars, the closest planet. It’s not inhabitable in any way that could be classified as “living,” and never will be. With all those galaxies containing all those stars and planets, is there a chance that another planet is out there that could support human habitation? Statistically, it seems possible that the extremely rare conditions and unimaginably sophisticated events that transpired here, or something similar, might be replicated elsewhere. We don’t know. Even if such a planet was identified, it might take more than one human lifetime just to get there to find out. And if there is one, it might already be occupied.
Point being, we’re on the one we’ve got, a rock hurtling through space and on which arose the conditions to support life—the basic chemical building blocks and the environment and billions of years for them to interact and evolve. If scientists are correct about the longevity of the sun, more than half of this planet’s useful time is past, and yet we still have a billion or more years to go before we need to find another celestial home. The only question is, will we still be around to make that journey when the time comes?
“Good planets are scarce and few
Earthworms and caribou
Strong food chains and tasty meals
Textiles and plants that heal
Iron mountains and skies of blue
Good planets are scarce and few.”*
*“Good Planets are Hard to Find,” written by Steve Forbert and released on his album Rocking Horse Head
Steve Ernst is editor and general manager, American Laboratory/Labcompare; [email protected]