Touring the Solar System
For those of us who were paying attention in science class (somewhere between 5th and 8th grade) we learned that our planet was one of the four in the solar system that is made of rock. The outer planets (don’t get me started on Pluto) are giant balls of gas and liquid methane. Jupiter is likely a failed star, unable, for whatever reason, to ignite and become our Sun’s smaller sibling. The rock closest to the Sun, Mercury, may have a bit of wispy atmosphere, but not enough to breath or support a creature in winged flight.
Between us and Mercury is Venus. Great name. Exotic place. It is covered in atmosphere but not one good for breathing. Too much CO2! This thick atmosphere causes a greenhouse effect. The sun’s heat doesn’t escape into space on the night side of the planet, so it is just constantly cooking. Any liquid water that might have existed has boiled off the surface. No one seems too excited to go there. Skipping over us for a second gets us to the planet that everyone has waxed on about forever as a place crawling in war like creatures (“War of the Worlds” to and through “Mars Attacks!”) who are either jealous of us or stand as a reminder that the good times can dry up and go away. But, however we conjure it, Mars appeals to us and has fired our imaginations since the days of the Roman Empire. We have spent billions of dollars sending probes and landers there. We now dig incessantly in the Martian soil in search of evidence of life, past or present. Elon Musk wants to live out the end of his life there. It appeals to us because we are, by nature, wanders. What we keep missing though, with our sights locked on this new horizon, is the realization that we inhabit the most exotic planet in our solar system.
We live on this globe that is mostly covered by an exotic material called water. H2O. If we look across the solar system and probably the universe. water exists primarily as ice. In most places it spends little or no time as liquid, going straight from solid to vapor, like when a comet comes in close to the Sun. Here on Earth (even in very dry places) it is a constant. When it evaporates into the atmosphere it doesn’t stay there for long, precipitating back down to the surface, as ice, snow, or water in what has been an endless cycle of renewal of life as we know it. We, and most other living things are composed mostly of water. In this intimate compact between life and water all civilizations have evolved, along with all our hopes and dreams, and it is part of all the blood, sweat and tears that have come into existence. And because, as we dangle here in space at just the right distance from the sun, this delicate dance creates the oceans, glaciers, rivers, deep lakes, ponds and even the nectar of flowers that bring life to this rock on which we stand.
Astrophysicists refer to our orbit around the Sun as the Goldilocks zone. Not too hot. Not too cold. Just right. In addition, our little orb is in a Solar System with two extraordinary “Comet Catchers” (namely Jupiter and Saturn) that over the eons have absorbed countless comet strikes that might have derailed evolution on this planet. Keep in mind Earth has been whacked by plenty of comets. They’re why we have water. Our atmosphere has been hot and cold. 165 million years ago it was very warm. All the time. No polar ice. No massive glaciers. The age of dinosaurs. This prompts some people today to say, “look, there hasn’t always been ice and snow here. We’ll be fine if it warms up.” An interesting perspective. Also remember that at the time all the continents were squished together into one giant landmass called Pangea. The oceans (which covered even more of the planet than today) teemed with life while we were not even a remote glimmer in any primitive mammal’s eye. Over thousands of centuries the continents were pushed apart as tectonic change happened on a grand scale and the climate shifted. This new climate that varies between large glaciers and small glaciers became the norm. We, whether we like it or not, are creatures that evolved on this alternately cooling and warming planet; as did most of our fellow travelers.
The question we now face is how far can we push the biosphere that brought about life as we know it? I tend to think about it this way. If we were building a fantastic, multi-generational spaceship to carry us to some distant star, would we bring along lots of extra CO2 to make the air hard to breathe? Would we have giant piles of burning coal strategically placed inside the ship to generate electricity? Probably not. We’d think it was stupid. I hate to break it to you but, we live on a giant spaceship. If someone else owned it, they would have evicted us long ago for damaging their property. But we, the selfish and destructive tenants, have nowhere to move. There’s no planet B.
Reversing the damage here is still very doable. It requires concerted effort. We have proven ourselves on several occasions of being able to do amazing things.
We need to stop risking the very environment of a world that gives us everything. It’s time to grow up. I am a firm believer that the planet will be just fine without us. If we can sort through how to keep this place from becoming inhospitable for us, we may finally begin to see how truly rare this third rock from the sun really is. Remember - our other mostly water co-inhabitants are counting on us. If you were asleep in science class, it’s time to wake up.