Against the backdrop of blue skies, crashing waves, and steep, rocky cliffs, and clad in his iconic rust-colored jacket, Carl Sagan uttered perhaps his most famous quote. In the first episode of his acclaimed television series, Cosmos, he said, “We are made of star stuff.” He was alluding to the awe-inspiring scientific theory called “supernova nucleosynthesis” which suggests that the elements we are made of, the wide variety of atoms that make up the planet on which we live, were formed in the fiery, dense hearts of ancient supernovae. Sagan states, “The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars.”
Without going into great detail, here are some brief notes on the process. Though the simplest element, hydrogen, makes up about 75 percent of the matter in the Universe, there is quite a large quantity of other stuff around; how did it get here? Well, a star is basically a huge oven, and at its core, it is tremendously hot and incredibly dense. The heat and pressure there fuse the nuclei of hydrogen atoms together to make helium, releasing a huge amount of energy. The outward “pressure” of the nuclear explosions happening inside and the inward gravitational pull of the star’s mass come to a sort of equilibrium, and the star becomes stable. This process goes on for many, many years, but at the end of a giant star’s life, it runs out of the hydrogen that has kept it “inflated” throughout its life. After the hydrogen has run out, the gravitational forces overcome the star’s structure, and it contracts. As this happens, the star’s core becomes even more tightly packed, which causes the helium atoms produced during the star’s main sequence to fuse into heavier elements like carbon, nitrogen, and so on. This process happens several times in a relatively short amount of time, forming bigger and bigger atoms until finally, the dying star explodes in an enormous burst of energy. In this final stage of its life, the star scatters the heavy elements it has produced during its last days throughout the Universe, where they can become part of a planet, or a comet, or perhaps even a part of us.
Now, how does this fit into our lives as Catholics? How can all this science mumbo-jumbo possibly be worth studying and understanding? Well, science is conducted in pursuit of the truth, and any truth about ourselves, our planet, or the cosmos simply cannot be contradictory to the revelation of God to his people. Since he is the Divine Creator, there can only be one all-encompassing reality, which must necessarily (and complimentarily, I think) include both the laws of physics and the Good News of our salvation in Christ. Both religion and science work toward a common goal: understanding God’s creation and our place within it. For more reading on this, an excellent place to start is in the Catechism of the Catholic Church, paragraph 283.
I think the idea that we are made of star stuff points to a deeper understanding of our oneness with God’s creation and gives a profound perspective on the Incarnation. God became one with his creation by taking on the human form and living among us. What a wonderful and significant statement. But perhaps we can gain a greater sense of wonder and astonishment of the Incarnation if we look at it with a bit of a cosmological flavor.
Perhaps we could realize that God, who wrote the laws of physics and guided the development of the Universe and the stars within it, became human by assembling atoms formed in a supernova explosion billions of years ago into a human body. God became one with his creation by becoming star stuff inside of time and space. Not only did Jesus share our human experience on Earth, but he unified himself to the whole cosmological history of the entire Universe. He became one with humankind, but he also became one with planet Earth, the moon, the planets of the solar system, the sun, the stars, and the hundreds of billions of galaxies throughout the Universe; he became one with everything. God, who is the creator of everything, and the author of the natural laws, sent his only Son to become one with Creation, to exist as we do, with a body made of star-stuff, and in doing so, perfectly reconciled the things of the world to himself that in Christ, God and his creation would be purely and forever unified.
This perspective makes it easy to see that no matter where we look, we see evidence of the Divine Creator. There is not one portion of creation reserved for the faithful, and some other portion reserved for scientists to study. There is only Creation. It is a magnificent and complicated creation that we, as a part of our lives as human beings, are invited to investigate. Science and religion are complementary, and it should be no surprise that scientific discovery, while shedding light on the natural phenomena we observe, can enhance our understanding of who God is and the mysteries of our faith.