Short Wave - Siriusly, It's The Dog Days Of Summer!

Episode Date: August 9, 2021

Ever wonder why we call it the Dog Days of Summer? Today on the show — Emily gives Maddie an astronomical reason why we associate the sweltering heat of summer with the dog star, Sirius. So, before the dog days are over, have a listen — perhaps as you head out to the sky in search of the dog star. You can email the show at [e-mail] pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, Duteritos, Maddie Safaya here. And Emily Kwong. So, Madi, how's your summer been? Buh, mixed bag, to be honest. You know my two moods in the summer on any summer are hot and sweaty. Yeah, same. It's the dog days of summer, that hot, sultry window of heat and humidity and napping in the AC.

I mean, I don't know if I'd go with sultry, but yeah. Okay, well, teach his own. Maddie, do you know why, though, it's called the dog days of summer, this period from July and to August? I actually have no idea. Like, I can't even make something up right now, Emily. Okay, I'll help you out. To uncover the historical origins of this term, we got to trace a path up through the night sky. Okay, to the constellation Orion and those three stars that make up his belt. Look at Orion's belt and there's a diagonal. Orion happens to be Kirsten Bowley's favorite constellation.

Kirsten is a Ph.D. student at the Ohio State University, and she says that if you follow that belt toward the horizon, if you're in the Northern Hemisphere, you'll find your answer. The next brightest star that you see should be serious, and that's on basically Canis Major, which is the dog constellation, and it's like the top of its chest. So you're telling me the dog days of summer has something to do with the dog constellation, Canis. Kind of. It has to do with Sirius. That's super bright. right, star on the chest of Canis. So here's the story. Ancient Greeks, Romans, and Egyptians all noticed that during the peak of summer, Sirius rose and set right next to the sun. It was so close to the sun that it kind of blended into the sun. And those ancient skywatchers thought it might be the combined power of those two

stars, our sun and Sirius, that sent temperatures soaring. Oh, so they thought hot weather was literally driven by dual star power. I mean, that makes sense. That makes sense to me. Yeah, and it forever associated Sirius, the dog star, with the heat of summer, even though we know now that it doesn't cause the heat at all. Yeah, among other things, the summer heat has to do with the tilt of the Earth's axis. This time of the year, the sun hits the northern hemisphere at a steeper angle, meaning energy hits the hemisphere more directly, butto-boom heat. Maddie's plain summer. There you have it. While Sirius is not to blame for your AC or.

obsession. It's still got plenty going for it. Serious, for instance, is a binary star. Ooh, what's that? Okay. It means that there's another star that rotates around it. It's got like a friend. Cute. Yeah, new research suggests that almost all stars are born in pairs. This isn't unusual. Sirius's companion is this faint white dwarf star that some astronomers call the pup. The Cuisan spoke very fondly of the pup. Although Sirius has a companion, you won't really be able to to see the companion by eye because it's a white dwarf, which means that it's a remnant of a star. So some star basically ran out of fuel. And so it's not burning anything.

It's basically just cooling off now. Wow. This story took a turn. I didn't expect the puppy star to be dead, Emily. I mean, the pup died 120 million years ago, but, you know, go off. Okay, another star fact, you may have noticed. that Sirius is the brightest star visible from Earth, aside from our sun. And that's because it's really, really big.

How big are we talking? Twice the size of our sun. And 25 times brighter. So if you were to put our sun besides Sirius, it would be brighter than our sun. But you got to remember that our sun is much closer. Right, right. It's eight light minutes away compared to Sirius, which is like eight light years away. So because it's farther away, it does.

doesn't appear as bright, which is probably a good thing because I imagine it is much, much hotter. Yeah, so think your lucky stars, you don't have to experience serious burn. Okay. Like from serious. No, I get it. Worst tan of your life. Okay. Why are you like this?

Anyway, ironically, in summer, it can be kind of hard to spot serious. Often it's obscured by dawn's early light as it's rising with the sun. But you might be able to in the wee hours of the morning. Just follow Orion's belt, like Kirsten recommends. And because it is the dog days of summer, shortwave nerds, we've got a treat for you. All this week, we'll be sharing some of our favorite conversations about real dogs, not celestial dogs, with some incredible scientists and science communicators. We'll talk about dogs in the lab, dogs in the mirror, dog love. We may even have a day where we give cats their due.

What do you think, Maddie? You're going to revive that cat versus dog Smackdown? It may be the dog days of summer, but that doesn't mean it has to be boring. And Catless. That's your tagline for Dog Week? It doesn't have to be boring, or Catless. It sounded better in my head.