Everything Everywhere Daily: History, Science, Geography & More - Carbon: Can't Live Without It

Starting point is 00:00:00 Every form of life which has ever been discovered, regardless of its size or how it metabolizes energy, has one thing in common. They're all based on the element carbon. Carbon is the most important building block for life. It holds a unique place on the periodic table, and it can combine with itself and other elements in so many different ways that there is an entire branch of chemistry devoted to it. Learn more about the element carbon, its importance, and future on this episode of Everything Everywhere Daily. What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed.

Starting point is 00:00:52 It effectively turned day into night. And how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. Carmen is a very special element. It's the sixth element on the periodic table, and it's estimated to be the fourth most abundant element. in the universe behind hydrogen, helium, and oxygen. However, it's only the 15th most abundant element in the Earth's crust. If you remember back to my episode on lithium, elemental abundance after hydrogen and helium doesn't necessarily correspond perfectly with atomic number. Carbon is created

Starting point is 00:01:30 inside of stars in a process known as the triple alpha process. In the triple alpha process, three helium atoms fuse together to create carbon. There are three naturally occurring isotopes of carbon, carbon 12, carbon 13, and carbon 14. Carbon 12 and 13 are stable, but carbon 14 is unstable and undergoes radioactive decay. And that is why carbon 14 is used for the dating of objects. I've previously done an entire episode on radiometric dating, but suffice it to say that by looking at the ratio of carbon 12 to carbon 14, you can determine the age of something. Carbon 14 gets locked in when something is alive and then decreases over time. All of the things I've just mentioned are not what makes carbon special.

Starting point is 00:02:12 What makes carbon special is its outer electron shell. The outer electron shell for elements in the first row of the periodic table can hold eight electrons. Carbon has four electrons in its outer shell, and this puts carbon in the Goldilocks region of the periodic table. It doesn't necessarily want to get rid of electrons like lithium, which is further to the left on the periodic table, and it doesn't want to grab electrons like oxygen, which is to the right. Because it has only half of its electrons.

Starting point is 00:02:40 shell filled, it can combine with a wide number of other elements in a large number of ways. Not only that, but it combined with other carbon elements in many different ways. And this makes carbon able to form incredibly large molecules. Polymers, proteins, and hydrocarbons are all large molecules based on carbon. And it can also create double, triple, or even quadruple bonds with other elements. For example, if carbon bonds with four hydrogen atoms, you get methane. Likewise, if it has two double bonds with two oxygen, atoms, you get carbon dioxide. Or it could have a triple bond with a single oxygen atom to create

Starting point is 00:03:16 carbon monoxide. And what makes carbon monoxide so dangerous is that only three of the four available electrons in the outer shell are filled. That last one wants to bind onto something, and it likes to bind to hemoglobin in blood. When it does bind to hemoglobin, it prevents oxygen from binding, which can cause hypoxia. In fact, it can bond with hemoglobin 240 times stronger than oxygen can, which is why it's so dangerous. Even a small amount of carbon monoxide can prevent your body from using oxygen, even if you're breathing in an oxygen-rich environment. There are so many possible combinations of molecules using carbon that there is an entire branch of chemistry devoted just to carbon, organic chemistry. True story, I was once at a grocery store in New Zealand

Starting point is 00:04:00 when I came across some table salt that was labeled organic, and all I could think of was, No, it's not. There's no carbon and salt. That's sort of the kind of things I think of. The subject of organic chemistry, DNA, proteins, and hydrocarbons are all subjects for future episodes, as each of those can be the focus of an entire lifetime study. The ability for carbon to create such a wide variety of molecules is why carbon is the basis for life, and why living things are often known as carbon-based life forms. More on that in a bit. Carmen also has the ability to bind with itself. Because it has four free electrons, it can do so in a number of different ways. The different forms of carbon are known as allotropes. Each different carbon aletrope has unique and exceptional properties. Perhaps the aletrope you're most familiar with is diamond. Diamond is carbon in a three-dimensional crystalline structure. The carbon bonds in a diamond are extremely rigid. Diamonds have the most atoms per unit of volume, which is why it's so hard and so difficult to compare. press. I've previously done an entire episode on Diamond, so I won't belabor the point, but

Starting point is 00:05:05 it's remarkable how different Diamond is from every other allotrop of carbon. The other common naturally occurring allotrop of carbon is graphite. Graphite is a crystalline solid that's made up of layers of flat sheets of graphene. Whereas Diamond has a 3D crystalline structure, graphene has a flat two-dimensional structure. The carbon atoms are bonded in a hexagonal pattern. While the bonds between the carbon atoms are relatively strong within flat sheets of graphene. The bonds between the sheets are actually rather weak. And this is one of the reasons why graphite is such a good lubricant. Ever since the 19th century, scientists have known that graphite was made out of sheets of carbon graphene. However, they were never able to isolate graphene from graphite. It was isolated for the

Starting point is 00:05:52 first time in 2004 by a pair of researchers from the University of Manchester. They used what is called micromechanical cleavage to separate it, but it's more commonly known as the Scotch tape technique. They used a weekly adhesive substance to remove single layers of graphene from graphite, which were only one atom thick. The researchers, Andre Gehm and Konstantin Novoselov, were later awarded a Nobel Prize for their work in graphene research. And fun fact, Andre Geim is the only person to have won a Nobel Prize and an Ig Nobel Prize, which is given for trivial scientific achievements. His Ig Nobel Prize was awarded for levitating a frog with magnetism. For the longest time, diamond and graphite were the only known naturally occurring allotropes of carbon.

Starting point is 00:06:39 In 1985, a new form of carbon was discovered when carbon was vaporized in a helium environment. The result was carbon molecules with exactly 60 carbon atoms. And it turned out the new carbon was in the shape of a sphere. It was dubbed Buckminster Fullerene, in honor of Buckminster Fuller. who popularized the geodesic dome, which looks like carbon-60. They are more commonly known as Bucky Balls. There is an entire class of fullerine molecules with different numbers of carbon atoms, and the largest fullerine molecule to date is a sphere with 3,996 carbon atoms. The discovery of Buckminster Fullerene and the isolation of graphene has had huge implications,

Starting point is 00:07:20 because it turns out they weren't that much different from each other. If you took a sheet of graphene and wrapped it around itself to create a cylinder, you would create what is known as a carbon nanotube. And likewise, a carbon nanotube can be thought of as just a bucky ball with two holes in it. So why is this important? Because carbon nanotubes have some of the most remarkable properties of any materials which have ever been discovered. For starters, carbon nanotubes have the highest tensile strength of any substance known. Tensile strength is the load a material can bear while being stretched. High-tenth-style strength is an important thing for things like cables and ropes. In the theory, a carbon nanotube with a cross-section of one square millimeter

Starting point is 00:08:03 could support a load of 6,422 kilograms or 14,158 pounds. That means something the size of a thread of dental floss could support the weight of three large pickup trucks. If we ever wanted to build a space elevator that could carry objects up to geosynchronous orbit? In theory, a cable made of carbon nanotubes or of a carbon tape of extremely long pieces of graphene could actually work. Tensile strength isn't the only incredible property of carbon nanotubes. They're also incredible electric conductors. Their use for transmitting electricity could someday revolutionize the electrical grid. They can also exhibit semiconductor properties depending on how they're made. There's already work being done on next-generation computer processors. Researchers at MIT have already built

Starting point is 00:08:53 prototype processors out of carbon nanotubes, which, in theory, would be faster than silicon. On top of that, carbon nanotubes can conduct heat incredibly well and have a high refractive index, which allows them to bend light that goes through it. These forms of carbon, whether they're in the form of a tube or a sheet, could revolutionize many industries, including electrical transmission, computers, clothing, cars, and aviation. If these forms of carbon are so, great, then why don't we use these forms of carbon and everything? It turns out creating tubes or fibers of any significant length is very difficult. Getting lengths beyond a few millimeters is really hard. The longest nanotube ever grown is only 50 centimeters, and that was done over a decade ago.

Starting point is 00:09:35 The key to wide-scale adoption of carbon nanotubes and fibers will depend on the ability to develop large pieces cheaply and at an industrial scale. And so far, this hasn't been accomplished. And creating these forms of carbon is very expensive. Before I talked about carbon-based life forms. All of the life forms that we know of, from viruses to bacteria, to worms on the seafloor to people, are all based on carbon. Many scientists and science fiction writers have wondered if it would be possible for non-carbon-based life forms to exist. The best candidate, other than carbon, would probably be the element silicon, which sits right below carbon on the periodic table. Like carbon, it has four electrons in its outer shell, and for that reason, many have speculated that it could form molecules

Starting point is 00:10:21 like carbon. We obviously will never know if non-carbon-based life is possible until we find it, but to be honest, the odds are very slim. We actually know quite a bit about silicon chemistry, and despite its electron configuration, it just doesn't behave the same as carbon. For starters, when carbon oxidizes, it forms carbon dioxide, which is a gas under temperatures and pressures which allow for water. When silicon oxidizes, it produces quartz, which is a mineral. It's been theorized that maybe, maybe such a life form could exist in lava or magma, but that would be beyond the boiling point of many of the lighter elements, which would then make the creation of complex molecules that much more difficult. And moreover, there's just way more carbon in the universe than

Starting point is 00:11:06 silicon, and amino acids, which are the building blocks of DNA, have been found in interstellar space. On top of that, silicon doesn't tend to form double and triple bonds, and it has a larger atomic radius than carbon, which affects bond angles, bond lengths, and bond strengths. So if we look for life outside of Earth, we should probably stick with what we know and look for carbon-based life. Carbon is really important. Life as we know, it literally couldn't exist if it wasn't for carbon. If we ever find life outside of Earth, it will probably also be based on carbon. And after a billion years of carbon-based life, it's possible that our lives could be transformed with new carbon-based technologies over the next several decades. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Thor Thompson and Peter Bennett.

Starting point is 00:11:59 Today's review comes from listener Demp City over at Apple Podcasts in the United States. They write, Working listener from Michigan. Consuming 10-minute snippets of information while I work truly makes my day more enjoyable and entertaining. The quick yet thoughtful content of each episode keeps me excited for more. Covering the Harlem Globetrotters to Pablo Escobar's hippos, I found very few episodes that don't strike my curiosity. I'm interested in English Bulldogs and the Appalachian Trail if you're willing to educate me more.

Starting point is 00:12:26 Keep up the great work and I look forward to many more work days with you. Thanks, Demp City. If you're listening to the show at work, you could actually listen to the podcast to use the Pomodoro time management technique. You set a task and work at it in a focused management. manner for about 20 to 25 minutes, which just so happens to be the amount of time it takes to listen to two episodes. And then when you're done, you get up, take a break before you go back to whatever you were doing before. Remember, if you leave a review or send a boostogram, you two can have it read on the show.

Everything Everywhere Daily: History, Science, Geography & More - Carbon: Can't Live Without It

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