Think about what happened the last time you took a breath, and consider the cosmic machinery that made it possible:
- Within your body, the oxygen that you inhaled got combined with the energy-storing molecules in your food to release energy. That energy was used by your brain, your muscles, etc., to leave the cosmos just a tiny bit different than the way it was before.
- The energy you used to make that cosmic change had to be packed into your food somehow. As we know from high-school biology, plants stored that energy in the food's constituent molecules, using CO2 from the air and sunlight as "feedstocks" for photosynthesis.
- One of the byproducts of your changing the cosmos was your release of a certain amount of carbon dioxide back into the air when you exhaled.
- Your exhaled CO2 will eventually be recycled by other plants — again using solar-powered photosynthesis — into still more molecules that will show up in foods, building materials, etc.
- Oh, and this: All those molecules we've been talking about? Every single molecule on the planet (apart from hydrogen and maybe some of the helium) is composed of atoms from the ashes of one or more exploded stars.
- And those dead stars? They came about as a result of a titanic process that's been in progress for billions of years, starting with the unimaginably-huge release of energy at (what we call) the Big Bang.
So let's sum up: We humans are part of a very-long-term process by which the energy from the Big Bang is being busily transformed into an ever-evolving universe.
If we wanted to speculate, we might even call this process a project — a continuing creation — in which we get to participate.
(Inspired by an NPR commentary yesterday by astrophysicist Dr. Adam Frank reminding us of the wonder of photosynthesis.)
