Learn about why natural selection favors superstitions; why the way our noses smell is way more complicated than we thought; and where scientists think Oumuamua, the first interstellar object, came from.
Learn about why natural selection favors superstitions; why the way our noses smell is way more complicated than we thought; and where scientists think 'Oumuamua, the first interstellar object, came from.
How natural selection favors superstitions by Cameron Duke
The way our noses smell is way more complicated than we thought by Cameron Duke
We might finally know the origin of the first known interstellar object 'Oumuamua by Grant Currin
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/an-interstellar-objects-origin-revealed-why-superstitions-evolved-and-how-the-sense-of-smell-is-more-complicated-than-we-thought
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about how natural selection favors superstitions; why the way our noses smell is way more complicated than we thought; and where scientists think the first interstellar object came from.
CODY: Let’s satisfy some curiosity.
Do you have any friends who believe strange things, like superstitions and conspiracy theories? Well don’t be too quick to judge, because we humans evolved to be that way. That superstitious behavior might not be an error in thinking, but an unavoidable byproduct of evolution.
Superstitious behaviors are often the result of seeing a pattern where none actually exists. The fancy term for this is “apophenia” [APP-uh-FEEN-ee-yuh], and it’s pretty common — thanks to the fact that our brains are really good at seeing patterns in everything. In fact, our survival depends on it. An ability to see patterns in nature is an obvious survival advantage; I mean, it’s good that you can figure out how the seasons affect your food sources — or what behaviors keep you safe from predators — because that kind of thing helps keep you alive to procreate. People who can’t connect cause and effect don’t tend to survive as well.
Natural selection is really good at discouraging harmful false beliefs, like “that snake won’t hurt me!” But natural selection doesn’t really care about harmless false beliefs, like “that snake was a bad omen.”
This is all because of the way behaviors evolve. Natural selection will help a behavior spread IF the likelihood of benefiting from it multiplied by the size of its benefit is greater than the cost of the behavior. The mouse that sees a snake and runs away lives to have babies, but so does the mouse that sees a stick and thinks it’s a snake. It’s a false belief, but it doesn’t pose a disadvantage to its survival. The mouse that thought the snake was a stick, though? That mouse was eaten a long time ago.
Evolution isn’t about perfection — it’s about making things “good enough.” So it favors spotting patterns, even false ones. Since telling the difference between a true pattern and a false pattern isn’t as evolutionarily important as the difference between seeing patterns and not seeing patterns, less-harmful false beliefs will inevitably make it through. Superstitions and conspiracy theories are a small price to pay for keeping our place in the gene pool.
Your nose is incredible. It can detect a huge number of different smells, and can even make sense of some incredibly complex smell mixtures. So maybe it’s understandable that researchers from Columbia University have discovered that the way our noses smell is way more complicated than we thought. So let’s talk about the surprisingly intricate way your nose knows.
When you smell something, you’re sensing rogue molecules floating through the air called volatile organic compounds, or VOCs. So let’s say the molecule vanillin wafts into your nostrils. It’ll find its way up to a thin layer of tissue deep within your nasal cavity that’s covered in neurons. And each of those neurons contains one scent receptor. When the vanillin molecule meets the right receptors, your brain gets the message that you’re smelling vanilla. There are about a thousand of these scent receptors, and it’s generally thought that a given odor will activate them in a pattern that your brain can decode to let you know what you’re smelling. Scientists estimate that humans can detect at least 1 trillion different odors, and we’re often detecting several at the same time. You can probably relate if you’ve ever walked down a city block and smelled coffee, car exhaust, and Indian curry all at once.
Exactly how the brain makes sense of all of those scents has been a mystery. Recently, a research team at Columbia University used 3D imaging techniques to watch how receptors in a mouse’s nose reacted to complex odors. This new approach allowed researchers to watch how hundreds of receptors behave, all at the same time — and what they saw was surprising. It turns out that the old idea about odors activating a handful of receptors was way too simple. Instead, odors can actually turn receptors off or on, or turn their response up and down. Sometimes one odor can even alter a response to a completely different odor. The authors even say that a molecule with no odor at all could alter the perception of another odor.
Perfumers have always known that different odors can mask or enhance each other. But researchers had assumed this happened in the brain, and not the nose itself. This means that smells are not simply the combination of odors the nose receives, but also how the individual scent receptors in the nose interact with each other to create the signal the brain receives. That means that every smell you smell is much more than the sum of its parts.
[CODY: It’s kinda like last week when Lisa Feldman Barrett was on our podcast. She talked about how there aren’t like, SPOTS in the brain where emotions come from. Instead, it’s more about how combinations of neurotransmitters talk to each other, followed by how you interpret those emotions]
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In October of 2017, a visitor from another star passed through our solar system. And it was the first confirmed interstellar object to visit our place in space! It was so strange, scientists actually scanned it for alien radio waves (they didn’t find any). They named it ʻOumuamua [oh-MOO-uh-MOO-uh], which is the Hawaiian word for “scout.” And now there’s a new study that may explain where it came from.
ʻOumuamua is small, reddish, and shaped like a cigar. It’s about 3,000 feet long and only 500 feet thick, or about 900 by 150 meters. First, scientists thought it was a comet, but they declared it an asteroid when they realized it didn’t have a comet’s characteristic tail. But then, they realized it was accelerating, which is textbook comet behavior. It was a big fat question mark until researchers in China and at UC Santa Cruz ran some high-resolution computer simulations and determined that it’s an “active asteroid” — a relatively new term for an asteroid that has some features of a comet.
They think ‘Oumuamua’s story began when a planetary body got a little too close to its star. By planetary body, they mean a big, rocky object that’s prominent in its solar system. Think planets, dwarf planets, and really big moons. Most of them are made of a lot of pieces of rock that are held together by gravity. One of the study’s authors said, quote, “You could imagine them as sandcastles floating in space,” end quote.
Objects like that can get in trouble when they pass near their star. When they get a little too close, it turns into a game of gravitational tug-of-war. The force of the star’s gravity can cause the planetary body to stretch and bulge. It’s a lot like the pull the sun and moon have on Earth’s oceans. That can also cause parts of a planetary body to break off, littering space with rocky fragments. That’s what the researchers think ʻOumuamua is: a leftover fragment that made a long, unlikely journey to our solar system.
Heat from the star that made ʻOumuamua break off also probably made most of the ice and other volatile substances boil off of its surface, but there could be more inside. As it gets closer to our sun, that ice may be melting and turning to vapor — and that might be why it’s accelerating so incredibly quickly as it passes through the neighborhood.
So no, ‘Oumuamua isn’t an alien spacecraft. It’s just a funny looking piece of rock that traveled a really, really long way to visit.
C: Let’s recap today’s takeaways
[ad lib optional]
CODY: Today’s stories were written by Cameron Duke and Grant Currin, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Today’s episode was produced and edited by Cody Gough.
CODY: Join us again tomorrow to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!