Have you ever heard someone say something dismissive about chemicals? Like comments that indicate these substances are somehow separate from us? It’s pretty common to see some people advocate for “natural” or “organic” products. Or, they preach against vaccinations because they wrongly assume these lifesaving injections are somehow “full of toxins and chemicals”.
It always sounds so silly, to me. I mean, the entire detectable universe consists of chemical elements. That means you and me and the planet and the Sun and Moon and… well, everything we can directly detect. So how can substances or objects consisting of chemicals be somehow unnatural?
Yes, I get that these people are often referring to specific things in vaccinations, for example. (Things that aren’t there, by the way. Or, they’re completely misunderstood or misinterpreted by people with a lack of critical thinking skills. But that’s a different topic.) That old argument about chemicals being somehow “unnatural” and “toxic” just ignores the reality of our existence.
Chemical Ingredients for Life Are as Old as the Universe
Take a look at your hand. Or the apple you’re eating. Or the coffee in your cup. And, the cup itself. Every object you can sense is made of chemicals. Or, to be more specific, chemical elements combined into molecules. Those are, themselves part of some kind of cellular matrix. I always liked the bit in the first “Cosmos” series where Dr. Carl Sagan suggested that, “If you wish to make an apple pie from scratch, you must first invent the universe.”
It’s true. The apple is a construct of atoms of elements that formed complex molecules. They combine to make the apple’s structure. So is the crust. So is the sugar (if you use that), and so are the other ingredients. And, so are all the things inside vaccines. In some cases,they have killed viruses that we wish to inoculate against. And, the viruses themselves are incredibly complex mixtures of molecules made of chemical elements.
So, where do those “fixin’s” come from? Why from the stars, of course. Other than hydrogen and a little lithium, most other chemical elements come from stars. So, calcium (for your bones), iron (for your blood), potassium (to regulate heart activity), and other elements, come from stars. They cook them up as they age and evolve, and when they die, stars scatter that “stuff” to the universe. There, it gets taken up (eventually), into clouds of gas and dust, which are the birthplaces of stars and planets. And, planets (as we suspect from our sample of one) are formation places for life.
Chemical Clouds Hold Clues to Life
We know that interstellar clouds contain hydrogen. That element was created in the Big Bang. The clouds also harbor complex organic molecules. Many of those substances are actually the building blocks of life. And, they seem to be in many such cloud complexes.
Astronomers, astrobiologists (the folks who study life elsewhere), and astrochemists (who study chemical elements in the universe) want to know how soon in the universe these molecules appeared. What causes their formation? In a disk of gas and dust, when do the building blocks of life appear? One suggestion is that they form in response to rising heat and pressures in a protoplanetary disk. That’s the part of the cloud where a star and its planets are born.
When Do Chemical Percursors Form?
At least one study shows that those complex organic molecules can exist long before a protostar begins to form. In that research, scientists found molecules of methanol and acetaldehyde in a large number of starforming regions called “pre-stellar” or “starless”. These places don’t have stars, yet. However, they seem to be places where cold dust and gases coalesce. There, they form the seeds that eventually will give rise to stars (and planets). And, according to the scientists who are studying these regions, they contain life’s building blocks, before worlds exist to take advantage of them.
These two molecules aren’t the only prebiotic precursors found in such clouds. A simple sugar molecule called glycolaldehyde has been detected, along with a host of other carbon-based molecules. These discoveries show us that we are in a chemical universe that provides the seeds of life.
Finding Chemical Precursors
To study the clouds for their particular discovery, a team of scientists at the University of Arizona’s Steward Observatory, used a 12-meter dish telescope to study emissions from interstellar clouds. They peered at 31 starless cores scattered throughout a star-forming region known as the Taurus molecular cloud. That cloud lies about 440 light-years from Earth. Each core is quite large, about the width of a thousand solar systems. None of the cores has a star at its heart, and probably won’t for several hundred thousand years.
That’s according to Yancy Shirley, who worked with graduate student Samantha Scibelli on the project. “This tells us that the basic organic chemistry needed for life is present in the raw gas prior to the formation of stars and planets,” he said. The processes that bring chemical elements together to form organic molecular building blocks of life aren’t well understood. “The exact processes at play are still being debated because the theoretical models still don’t quite match what we see,” Scibelli said. With the current research, she and the team can constrain the formation sequence that might be taking place in the clouds.
Their work will tell theorists how abundant these molecules are. Eventually, it may be possible to figure out exactly how these molecules form and why they exist where they do. That would open up a wider range of places to study the chemicals that create life. (You can read more about this specific research here.
Accepting a Chemical Universe
It’s thanks to the prebiotic molecules that formed in our local neighborhood that we even exist today. Studies like the one at Arizona are the first steps toward trying to figure out where life exists elsewhere. Even more intriguing: it plays a big role in revealing where life could form next. And, we have chemical elements to thank for it. We’re all made of star-stuff, which is, in turn, made of chemicals. So, now I wonder, what could be more natural than chemicals? After all, they’re what we are.
