I was eating some hard-boiled quail eggs this morning.
These Coturnix quail really put out, and we've got bowls of the things sitting around. Lucky for us. They're delicious!
I was thinking about the fact that these little birds are magical factories for turning grain into protein. And about all the crazy steps our bodies take when we eat that protein, to disassemble the eggs down to the amino acid level and put them back together in forms we can use.
Metabolic pathways are more complicated than the US tax code. We didn't even figure out the Krebs cycle until the late 1930s, and I doubt there are many practicing doctors that could explain it to you step by step without consulting a textbook.
Protein folding and synthesis is another level of crazy magic entirely. A shit-ton of work goes into every one of those quail eggs. And the quail just poop 'em out!
Life is going on at so many different scales.
All the way down you've got the molecular level: carbon atoms are tossing around electrons like swingers at a key party. They form wilder and wilder combinations with nitrogen, hydrogen, and oxygen.
Wave a magic wand or wait a billion years1, suddenly those carbon-heavy molecules combine into factories for churning out proteins, including DNA that can self replicate. So you've got basic single celled organisms. Then there's bigger, more complex ones which the simpler ones move into (mitochondria!) happily pumping out energy for the larger cells in what's got to be the most intimate form of symbiosis in the history of the planet: Eukaryotes, y'all.
Bacteria start grouping up into multi-cellular forms of life, which form organs and organ systems and eventually entire bodies. Not that the bacteria is done for at this point. Far from it. Even though we're unaware of it, we've got more bacterial cells within us than we have cells that are us. We're more like walking colonies then people.
Plus we've got things like red blood cells that circulate and white blood cells that go around zapping the baddies with a level of agency and self-determination and, by all appearances, a great sense of job satisfaction.
Thanks to 
At each level of complexity, life seems utterly oblivious to what's going on "above" and "below" it in terms of scale.
Those lymphocytes, for example: inasmuch as they're "aware" of their immediate environment, they seem perfectly happy to attack invading cells and vigorously prosecute their jobs, while remaining utterly ignorant of the larger body they keep healthy with their actions.
On more relatable levels, our quail don't have any idea they're supporting us with their handy, pill-sized pods of egg protein. Suckers! we think. They don't even care that we're eating their eggs.
We fancy ourselves superior because we can see the big picture.
Are we really, though? Think for a minute about what you do for work.
Personally, I could go back to work at a corporate chain store and devote myself entirely to the daily struggles of sales figures and merchandising strategies, and actually be a pretty effective middle manager. That doesn't mean I'd have any clue about what I'm doing for the larger corporate body and it's shareholders - who likewise wouldn't give two shits about me so long as the dividend checks kept rolling in.
Biological systems scale way down. But they get huge, too: you could argue that communities, economies, and ecosystems are just extensions of the same processes, writ large. In my business example: bad decisions made at the store level can spiral out of control and wipe out a company, which can lead to lost wages dragging down the welfare of a country. The consequences touch on politics: a lousy trade agreement can disrupt things on a global scale and lead to all-out war.
I doubt there's anyone up there at the pinnacles of power who really understands everything going on below them - even if they have tickets to the Bilderberg conference. Things are just too chaotic and complicated2.
So why is it that, after we extend life to the global level, there's a lid clamped down over our sphere of influence?
Why this particular barrier? Why this membrane?
Carl Sagan's Pale Blue Dot speech is so moving because it shows just what a tiny, insignificant speck we are in the greater universe.
And by "we," I don't mean "we people." I mean, "We, Life."
Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam....
The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.
Once you start to realize how vast and interconnected living systems are - from chemical interactions through biology to psychology and culture - it feels impossible to accept that it all comes screaming to a halt right at the boundary of space.
Yet, other than a few astronauts spinning around in orbit, and maybe a handful of tardigrades clinging to the hulls of distant satellites, all the wildly complicated interplay of life comes to a sudden stop just a few miles above the surface of the planet.
Out in the bigger picture of the universe, things are still interconnected. The cosmos is wired together by chemistry and physics. There's the play of gravity and light, the hum of the cosmic background radiation, quantum particles popping in and out of existence, and whatever the hell dark matter's up to. And even though we don't know what goes on behind the event horizon of the black holes, we still know they're doing their part to pull us closer.
But the influence of biology ends with the vacuum. "The sky is the limit." Terminus Est.
A butterfly flickering its wings in the Amazon may bring a hurricane to your town, and every glass of water you drink contains a few molecules that passed through Julius Caesar's urine (and mine too!) - but despite your most herculean efforts, nothing you do here is going to impact events on Alpha Centauri. Or even on the moon3.
Footnotes
1. Yeah, we're oversimplifying here. What did you think this was? College?
2. I think this is why we pray to an omniscient god. It's comforting to think there's one mind in the universe capable of really understanding everyone.
3. Feel free to prove me wrong on that last point, though. I would love to be wrong about this.