Suppose we could fly to another solar system or even to another galaxy. In that case, we will find the same chemical elements we know very well here on Earth. Not only chemical elements but also molecules that we are familiar with. The most surprising thing we discovered in space is maybe water (depending on who you ask). Still, there is also methanol (wood alcohol), ethanol (yes, the same alcohol found in alcoholic beverages is present in space, particularly in molecular clouds), formaldehyde, glycolaldehyde (essential for RNA) and the everyday propylene used to make plastic bags here on Earth. Distant and cold, the cosmos is not as unfamiliar as we think it might be.
How do we know about these without physically going there?
We use telescopes. Combine that with a spectrograph, and the Universe unfolds without ever leaving your armchair. A spectrograph is an instrument that splits light (or, more generally, electromagnetic radiation) into its constituent wavelengths, producing a spectrum. This, in turn, provides a wealth of information about that object’s composition, temperature, density, mass, distance, luminosity, and relative motion.
In our quest to understand the universe and its vast complexities, we often turn to a cornerstone of chemistry: the periodic table. This table, with its neatly arranged boxes and symbols, represents the building blocks of the universe—especially what we identify in our “matter” basket for young learners.
92: Matter’s Intricate Tapestry: The Naturally Occurring Elements of the Universe
Out of the many elements listed on the periodic table, only 92 are naturally occurring, spanning from hydrogen, the lightest and most abundant, to uranium, the heaviest naturally found element. These elements compose stars, planets, rocks, oceans, and even the cells in our bodies. They’re the substances that make up the tangible world we interact with daily. As far as things that we can see go, the entire Universe is only made of these 92 chemical elements we know so well from the periodic table. Is not like you can go to another planet or solar system and the laws of chemistry will be different there, or we would find different types of naturally occurring elements. Perhaps, to paraphrase the Hitchhiker’s Guide to The Galaxy, the answer to the Universe and everything is 92.
Yet, it’s crucial to recognize that this “matter” we see and feel—known as baryonic matter—constitutes just about 5% of the universe’s total content. The vast majority is hidden from our view, being dark matter and dark energy, mysterious entities that challenge our understanding of the cosmos.
Beyond the 92 naturally occurring elements, scientists have synthesized additional ones in laboratories. These man-made elements, while intriguing, are transient; they decay quickly and aren’t found in nature in any substantial quantity. Their existence stands as a testament to human curiosity and our push to explore the boundaries of the natural world.
Out of these elements, six are indispensable for life: CHNOPS – Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus and Sulphur. When the rover Curiosity went to Mars, it first looked for these, and found them.
When teaching the periodic table and introducing the “matter” basket, it’s essential to emphasize that these elements, vital as they are to our observable world, represent just a fragment of the universe’s broader composition. Yet everywhere we look, the matter we see is the same as the one we observe on Earth.
With this perspective, we can inspire students to delve deeper into the mysteries of the universe and our place within its vast cosmic tapestry.
The periodic table song
There are a few versions of this, but this version is by far our favourite. Enjoy.