When we look up at the night sky or try to count the number of galaxies we think might exist – a number with a trailing line of zeros – it can be hard to conceptualize just how big our universe really is. That can make us feel separated; how could human beings infinitesimally small compared to their own planet, let alone the entire universe, play any part in the cosmic story unraveling around them?
It’s important to remember that our planet is just as much a part of the universe as any star we see out in space. Every one of us, and everything we touch or see or do, is made of the universe. Let’s think about this in terms of the Big Bang and the material created during the start of the universe.
As far as we know, there was nothing before the Big Bang, which we think happened about fourteen billion years ago (The implications of the term “nothing” raise more questions, of course – see Stephen Hawking’s article here for more.). The first atomic particles were created during the moment that this explosion happened, and in the first few minutes of the universe’s existence, hydrogen and helium were created in a process called nuclear fusion.
This hydrogen and helium were released, free to travel outward in all directions. Accompanied by photons – small particles of energy in the form of light – some of the particles collected in areas that were denser. These concentrations of particles swirled together over time to form stars and galaxies like the ones we see in our night sky today.
These stars continued to create hydrogen and helium at their cores by fusing together atomic nuclei. Though it took billions of years, (more on life cycles of stars at Space.com) some of these stars eventually exhausted the fuel at their cores and started to die. The end of this process involved stars exploding in giant supernovae and then collapsing into black holes. During a supernova, pressure and temperature reach such high levels that fusing together even more atomic nuclei can create new elements. In regular cores of stars, there is not enough heat or pressure to enable these reactions. All other elements aside from hydrogen and helium were created from supernovae – carbon, neon, oxygen, silicon, iron – elements that we hear about every day (Smoot Group).
When a supernova happens, these elements are projected out into space. In turn, they collect with hydrogen and helium in other denser areas of space and collect into stars, galaxies, cosmic material like asteroids, and planets like Earth. So every ring of Saturn, every crater on the Moon, every person on planet Earth is made of material that was produced in the very cores of stars. Material that was constructed during the Big Bang is part of the ground that we walk on and the energy that we use, and more dirt and dust from space falls down to Earth every day.
We are an active part of the aging universe. Elements that were catapulted through space and into the center of stars and back out again are the same elements that run through our veins. It’s easy to feel like space is far away, but it’s also important to remember that we are, in a very literal sense, the universe.
