Image from clipartpanda.com
Halloween is coming up, and popular culture is being filled its annual dose of references to the supernatural (including the recent season premier of the show Supernatural, which is probably not a coincidence). Ghosts, monsters, black magic, vampires, witches, and others all fall under this umbrella of “the supernatural.”
But what does it mean to be supernatural?
My dictionary defines “supernatural” as “(of a manifestation or event) attributed to some force beyond scientific understanding or the laws of nature.”
Being beyond scientific understanding is actually very mundane. Most of the way the brain works is beyond our current scientific understanding, but no serious researcher is throwing up his or her arms and declaring it supernatural. The relationship between mass and energy was beyond scientific understanding until Albert Einstein figured it out. The origin of mitochondria and chloroplasts were beyond scientific understanding until Lynn Margulis figured it out. Every issue of every scientific journal is filled with things that were beyond the understanding of science just a year or so prior. This is not what people mean when they say that something is supernatural. They mean the second thing — beyond the laws of nature. The word supernatural literally means “above nature,” or, more figuratively, outside or separate from nature.
But what is nature and what are its laws?
Consulting my dictionary once again, “nature” is defined as “the phenomena of the physical world collectively, including plants, animals, the landscape, and other features and products of the earth, as opposed to humans or human creations.” And once again, my dictionary fails to provide a completely cogent or useful definition. If humans and our creations are not natural, does that mean that the computer I’m writing on is supernatural? Again, no one would reasonably make this claim. The first part of this definition, “the phenomena of the physical world collectively,” is actually pretty good as it is. Nature, or the physical world, is made up of two things: matter and energy, which Einstein showed us are the same thing. Nature is everything that exists. It is all of the animals, plants, fungi, bacteria and all of the rest of life. It is all of the rocks and minerals and water and air. Even humans, which are animals, are part of nature. Everything beyond our planet is part of the natural world, as well. All of the undiscovered types and forms of matter and energy are part of nature. Every answer to an empirical question is part of nature, and it is the job of scientists to discover nature as it exists.
Are ghosts real? This is an empirical question because the answer is not subject to ideology or personal preference. It’s not possible for ghosts to be real for me but not real for someone else, any more than the statement “the earth’s atmosphere is 78% nitrogen” can be real for me but not real for someone else. Correct answers to empirical questions are correct whether you like it or not. Likewise, either ghosts are real or they are not. If they are real, they are part of nature, and are therefore natural phenomenon. It may come as a surprise to people that, if ghosts are real, it will be scientists who discover them. This is true of everything else that is commonly labeled as “supernatural.” If everything that exists is part of nature, then what does that mean? If something is truly supernatural, it doesn’t exist.
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3 Comments | tags: Albert, Angel, Animals, Atmosphere, Bacteria, Biology, Brain, Chloroplast, Einstein, Endosymbyosis, Energy, Existence, Fairy, Ghost, Human, Journal, Landscape, Leprechaun, Life, Lynn, Magic, Margulis, Matter, Mineral, Mitochondria, Monster, Natural, Nature, Neuroscience, Nitrogen, Philosophy, Physical, Planet, Plants, Reality, Religion, Rock, Science, Scientific, Supernatural, Vampire, Water, Werewolf, Witch, World | posted in Science
Image from “Little Shop of Horrors.” Linked from filmlinc.com
Most of us are taught in school that plants make their food out of sunlight. While this is true in some sense, it is easy to miss what is really going on inside plants. Plants are sometimes depicted as receiving sustenance directly from the sun, just as we do from eating food, but this is not correct. I recently encountered a person who, upon hearing that plants make their food out of sunlight, believed that plants harness Einsteinian physics to convert energy into matter. This is not such a strange thing to believe, given the ubiquity of the “plants eat sunlight” meme. I want to set the record straight in this post.
So what do plants eat? The short answer is that they eat glucose. Glucose is a simple sugar and it is the same thing a lot of other organisms eat for food. What’s different about plants (as well as some bacteria and protists) is that they make their own glucose. When animals want to eat glucose, they need to eat something that is already made of it. When we eat plants, a lot of the nutrition we are getting out of it is the glucose. Unlike animals, plants have the ability to build glucose out of other molecules — carbon dioxide and water. Once plants have built glucose, they can use it as a building material and they can us it as food.
But what is food really? Food is energy stored in chemical bonds. When the chemical bonds are broken, the energy is released and can be used to power different body functions (a few more steps are involved, but this is the short version). Carbon dioxide and water are relatively low-energy molecules. Glucose has much more energy, and turning carbon dioxide and water into glucose requires the addition of energy. Plants harness the sun’s energy to make this happen. Glucose molecules are therefore vaguely analogous to batteries. Breaking down glucose into carbon dioxide and water is like releasing the battery’s charge, and combining them back into glucose is like recharging the battery.
So do plants make their food out of sunlight? In one sense, glucose is made out of carbon dioxide and water, not sunlight. In another sense, the point of making glucose is to capture the energy from the sunlight. Water and carbon dioxide combining to form glucose is the vessel that carries that energy.
Venus Flytrap. Image from wikipedia.org
What about carnivorous plants, like the pitcher plant, venus fly-trap and sundew? These plants have evolved to trap, kill and digest animals. Carnivorous animals eat other animals for the protein and fat, but this is not the case for carnivorous plants. Plants need carbon dioxide and water to make glucose, and carnivorous plants are no different — but these are not the only molecules that plants need to thrive. Plants need to make proteins and other molecules that cannot be built using only carbon dioxide and water. These require nitrogen, phosphorous, potassium, calcium, and other molecules. Carnivorous plants live in environments where these other nutrients are rare, and it is these nutrients that carnivorous plants are after when they eat animals.
Have a topic you want me to cover? Let me know in the comments or on twitter @CGEppig.
4 Comments | tags: Animals, Carbon Dioxide, Carnivorous, Energy, Fat, Food, Glucose, Molecules, Nitrogen, Oxygen, Phosphorous, Pitcher Plant, Plants, Protein, Sun, Sundew, Sunlight, Venus Flytrap, Water | posted in Science