This week, "New @ MPL" is proud to showcase the writings of local teens and young adults from MPL's very own Teen Writing Group. (Our Teen Writing Group meets every Monday afternoon at the Library.)
Today, enjoy this entry from Bruce Howard, who takes us on a tour of very ancient history:
The "nearby" Andromeda Galaxy -- located 2.5 million light-years away
It is almost quintessentially human to ponder matters of history and to perceive the passing of time. In my early twenties, it’s sometimes easy to feel like you’ve been around a while. I’ve been through 16 years of schooling (with about seven more to go before I’m done). I’ve also witnessed several world-, nation-, and life-changing moments in history.
However, I did not just suddenly appear out of nowhere, a newborn baby in a foreign universe. The rules of physics might have a few problems with that scenario. I’ve been alive for less than .0000002% of the time the universe has been around, and inevitably, that which came before me factors into who I am.
Obviously, I directly owe my existence to the fact that my parents met. If that were the only factor, though, this wouldn’t be much of a story. Stepping a bit further back, I can trace my ancestors to World War II, World War I, the Civil War, and even the American Revolution. War is quite obviously a dangerous thing, so it might seem a bit odd to note that had my ancestors not been in these conflicts, I might not be here. Consider this: a young soldier heading off to war would have to put starting a family on hold for the duration of his service. If not for that setback, perhaps that soldier would never have had a child when they had your mother, father, grandmother, grandfather, and/or other ancestor. One might even say that every little thing that has happened since the rise of humanity has, in some way or another, affected today’s world. There is that famous quip about how going back in time and killing a single animal could drastically change the present. But I don’t want to stop this tour of history at the rise of humanity.
There are approximately 13 billion years of universal existence. So let’s start a bit further back than the mere dent in time that is human existence. Shortly after the universe was created some 13 billion years ago, in what is called the Big Bang, the universe had expanded a bit, enough that the universe was able to cool some and allow particles to combine. Thus, the first atoms were formed. These were mostly hydrogen, with only small amounts of a few other elements (like lithium) forming. If only these very light atoms had formed in the Big Bang, one might wonder how it is that the atoms we’re made of formed.
Drawing an atom
As the universe continued to expand, gravity did its thing, pulling the hydrogen and trace elements together. Eventually, these elements had formed clumps. Then, in time, these clumps had condensed enough to reach the conditions necessary for nuclear fusion. These giant balls of mostly hydrogen gas had become the universe’s first stars. Stellar nuclear fusion is the process by which stars continually produce their energy. A few nuclear processes steadily convert hydrogen atoms into helium atoms, giving off other things as well. Among these are light, along with somewhat elusive particles called neutrinos that have been the focus of intense study recently. Indeed, this has been the focus of my research experiences. The process of converting the maximum amount of hydrogen to helium takes varying amounts of time. However, after this process is complete, the star will then convert helium to heavier atoms, and then those atoms to heavier atoms still. This process will continue on until the star runs out of fusion material. If the star has enough material, it will continue undergoing fusion until reaching iron. Due to nuclear properties, it stops being energetically preferable to fuse elements heavier than iron. This concludes the fusion process. Big stars, those several times the size of our sun, will supernova after ending its fusion process. The supernovae produce incredible energies, allowing elements heavier than iron to form. In the process, the star’s material is ejected into the vast … space … of space.
So, after these early stars went supernova, their heavier elements (among them oxygen, carbon, iron, and others necessary for life) mixed in with other hydrogen nuclei. By approximately five billion years ago, some of the mix that had been made by prior stars had collapsed to form the Sun and its satellites. Contained on Earth were carbon, oxygen, iron, and the other elements necessary to produce life as we know it. Fast forward upwards of five billion orbits of the Sun, and here we are, inhabiting the Earth today. We are literally made of star atoms.
The closest star to Earth -- our Sun
So, clearly, both human history and cosmological history play quite prominently in determining how it is that a person came to be here and now. The cosmic story doesn’t end with us, though. What about the future of the universe? Our sun has about five billion years of hydrogen-burning left. Once it starts to fuse helium, it will swell, making Earth uninhabitable. If we can find a way to inhabit another planet or another system by then, the story of humanity can continue with that of the cosmos. Who knows when the end of the universe will be? A lot of that depends on certain parameters like dark energy -- which, notably, was only discovered 14 years ago.
I feel that it is a very neat thing that we can trace our lineage to the stars. As you can see from this musical YouTube video below of several talks put together, I’m not the only one. However, while it is easy to get caught up feeling small when thinking of the universe as it is, there are some important things to remember. We may not have a long life span in terms of the life of the universe, but that doesn’t mean we can’t do beautiful things with it. What we do in our lives can affect both the world itself and the generations to follow. These effects can, in turn, affect the generations to follow them. Who knows? One day, those effects might even be carried to other planets or other star systems. It’s the human perspective that guides our lives, not the cosmic perspective, from which we appear to be mere mayflies. And remember, you’re all stars in my book.
-- Post by volunteer Bruce Howard
(For more on the history of space and time, check out MPL's cosmology collection.)
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