The Fresh Perspective Podcast - Episode 26

How’s it going everyone? I’m Nick and you are listening to the Fresh Perspective Podcast.

You’ve reached part four of our guided audio tour of the night sky! Tonight, you will be given the steps needed to locate the constellation Boötes, (properly pronounced “Boh-OH-tease”) otherwise known as “the herdsman.” Do these stars depict an ancient rancher, an inventor, a hunter, a king, a winemaker, or the grandson of a werewolf? We will see if we can find out by exploring several of the myths tied to these stars. We will then wrap this episode up by dipping our toes into one of the deepest cosmological mysteries of all time known as the “Boötes Void!”

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The Boötes Void shouldn’t exist. Our current models of the big bang and the expansion of the universe work extremely well. They accurately explain almost everything we observe about the cosmos itself. The big bang theory has incredible predictive power, but only to a point. When we use that theory and its models to try to explain the Boötes Void, we end up with a giant question mark. It is one of the biggest unsolved mysteries of the night sky. But before we dive into that strange abyss, let’s see if we can spot Boötes himself.

Boötes is often described as the big ice-cream-cone-shaped constellation. It contains the third-brightest star in our sky and five of its stars have their own planets. It is easiest to spot in the spring and always follows just behind Ursa Major, the big bear. This is where we’ll start. To find Boötes, draw an imaginary curved line that begins with the three stars of the little dipper’s handle. Keep going past and behind the handle in that same arc. After you fly past a few dimmer stars, your nice wide arc will run directing into a really bright star. It is a star that has consumed all of its hydrogen and has swelled in size, shining with 133 times the luminosity of our sun. That star is Arcturus! To remember this trick, just think, “Follow the arc to Arcturus.”

The bright star that you are looking at now is at the bottom of the ice-cream-cone shape. Although, I’m sure, this is not at all what the ancients imagined, I like to think of Arcturus as the overlapping ankles of the herdsman, as he stands like a ballerina, with his long boots pointing out to his left and right. He probably isn’t a very good herdsman with those giant boots, but I digress.

The upper-body of Boötes leans toward the tail of the great bear as if he has a rope connecting him to Ursa Major, who is pulling him along. You’ll notice that he has a very narrow waist. If he is facing us, then the next star we find is on his right hip. “Izar” (meaning “loincloth”) is the name of that star, and it is 300 light-years away. Izar is actually a triple-star system containing a bright orange star orbiting a central point with two smaller blue and white stars.

Moving on to the herdsman’s right shoulder is the star, “Delta Bootis.” It is also called, “Princeps” meaning “Prince,” which I like better because it is with that arm that you can imagine him holding the crown that is Corona Borealis, the U-shaped constellation, to his right.

The next star marks the neck of the herdsman. I say it’s his neck because the name of the star is “Nekkar.” It means “cattle driver” or “rancher.” Nekkar is 215 light-years away and used to be a blue-white star. It is now a yellow flare star. It’s called that because it is a kind of star with unusual magnetic activity, causing it to irregularly produce bright flashes that each last only a few minutes.

The left shoulder of Boötes, the one closer to Ursa Major is Seginus, shining from 85 light-years away. It is a Delta Scuti type variable star, which means that, among other things, its brightness and size rapidly oscillates, making it useful to asteroseismologists who study the inner workings of stars. Some depictions of this constellation show Boötes holding his left arm up high, as if he is pulling back on the leashes of his dogs. If the night is clear, you may be able to trace up from his shoulder to find his elbow and hand.

Found at this rancher’s left hip, we see Rho Bootis, another orange star. I like to think that if Boötes has a belt, it is definitely an orange one, given the kind of stars that make it up. Rho Bootis is 160 light-years from us. It is 10 billion years old, and is moving toward us at a speed of about 30,000 miles per hour!

Let’s now jump down to the big boots we found before. The star at the herdsman’s left boot’s toe is Muphrid. It is one of the closest stars we’ve found at only 37 light-years away. It is also a close neighbor to Arcturus. Only 3.24 light-years separate the two stars. Unlike most stars which are made of mostly hydrogen and a little bit of helium, Muphrid is comprised of an impressive collection of heavier elements.

Finally, the star at Boötes’ right toes is Zeta Bootis. Zeta Bootis is another binary star system, found 180 light-years away. The cool thing is these two giants are the same size, rather than what is more usual, with one member of the binary being much larger than the other.

In our episode about Ursa Major, you may remember me talking about the mythological story of Zeus and his mistress, the nymph Callisto. Many storytellers over the ages pointed to the little dipper, Ursa Minor, and identified him as Arcas, the great hunter, and son Callisto, who nearly accidentally killed his mother when she was in the form of a bear. To save them both from this tragedy, Zeus turned the boy into a bear and spirited them both into the night sky as constellations. But just like with today’s comic books, non-cannon fanfictions, or conflicting religious texts, classical mythology is filled with imaginative alternate endings and “what-if” scenarios. What if Arcas never hunted his mother? What if he grew to adulthood, raised by his villainous maternal grandfather, king Lycaon? To many storytellers, this alternate ending of the story is where we get the constellation Boötes and the mythological origin of werewolves.

Lycaon’s people were barbaric and engaged in cannibalism and ritualistic human sacrifice. Once a devoted worshiper of Zeus, Lycaon grew to despise the king of the gods. Perhaps this had to do with Zeus’ treatment of his daughter, Callisto. Maybe he grew jealous that Zeus showed favor to his grandson. One day, Zeus joined the king at a dinner party. As a cruel trick, and to show his subjects that Zeus really wasn’t all-knowing, King Lycaon had his grandson Arcas sacrificed and secretly served in a meal to Zeus. (In some versions, it was one of Lycaon’s sons, such as Nyctimus, who was actually the one sacrificed.)

By the way, cannibalism shows up a few times in Greek mythology. We have even run into it before with the story of Cronos. I’m sure this trope has some meaningful archetypal message behind it, but to our modern sensibilities, these stories come off as bizarre, at best.

Of course, Zeus recognized what had happened immediately and threw the meal over the table in a fit of fury. Many things fueled his rage. He was mistreated as a guest by a king who should have been a gracious host. He was also the subject of a vile plot meant to humiliate him. His lightning cracked through the dining hall and he struck dead all of Lycaon’s supporters including his 50 sons. With another flash of light, he cursed Lycaon by turning him into a she-wolf. This is why the king’s name can be found in words like “lycanthrope” and “lycanthropy,” the supernatural transformation of a person into a werewolf.

As a demonstration of his true power, Zeus brought Arcas back to life, to reign in his grandfather’s place. Soon, Arcas learned that his mother had been cursed by a goddess (either Artemis or Hera), and doomed to wander the earth as a bear. He spent years looking for her, trusting his faithful hunting dogs to follow her scent. Eventually, he found her, and took care of her, ensuring that no harm would come to her. “Arcturus,” the name of this constellation's brightest star, comes from the Greek word meaning "guardian of the bear." Arcas would later go on to become a great king who reformed the kingdom. He taught his people how to weave and how to bake bread. After his reign, the land was renamed Arcadia, recognizing him as its noble founder.

Which ending of the story do you like better? Did Arcus become a celestial bear, or a great king, and grandson of the first werewolf? With Greek and Roman mythology, there often aren’t “official canonized versions” of these stories, so you are free to tell the version you like best.

Other myths are attached to this constellation as well. One simple story is that of an inventor. Boötes was the first person to create the plow. The agricultural goddess Ceres (as in the dwarf planet Ceres and the root for the word, “cereal”) was so impressed that she immortalized him in the stars. Today, he is still driving his plow with the help of several oxen. But maybe this constellation isn’t of Arcas or Boötes. Perhaps it depicts Icarius, a master wine-maker and prized student of the God of wine and theatre, Dionysus. When the ancient Chinese looked at these stars, they saw great weapons of war, a king’s throne, and a dragon’s horn. Some Native Americans saw these stars as a fish trap. Most interesting to me is how the Egyptians saw these stars. To them, it looked like the forelimb of an animal, like the paw of a dog, or the leg of an ox.

I can enjoy some mythology as much as the next guy, but the real story that comes from Boötes deals with the scientific mystery it conceals. The time has come to gaze into the abyss, one of the most massive, empty, dark, and spooky parts of the entire universe. Go back to Nekkar, the star we visualize as being in the center of the neck of the herdsman. Now take a moment to visualize the head of Boötes just above it. Imagine that Boötes’ head is turned in profile, facing the tail of Ursa Major. Ignore the last star of the bear’s tail and look at the line created by its other two stars, Alioth and Mizar. If you trace a straight line from the first two stars of the bear’s tail to where the eye of Boötes would be, you have crossed over the void. The center of the Boötes Void is actually about one-quarter of the way between his eye and the tail of the bear.

In 1981, American astronomer Robert Kirschner was studying the big bang, inflation, and the expansion of the universe. He was measuring the changing distances between galaxies when he came to this exact section of the sky. What he found sent chills down his back. You see, the big bang theory predicts that matter and energy should be spread out across the universe in pretty predictable ways. All the matter and energy was once equally spread out, and gravity and dark matter worked to clump everything into stars and galaxies here and there. Galaxies clumped together, and over time, the universe looked more and more like how we see it today. So, what should we do if we find a giant hole in the universe? When I say giant, I mean it. This void is roughly sphere-shaped and has a diameter of 250 million light-years. In that space, there should be about 10,000 galaxies. So far, we have only found about 60. Where did all the other galaxies go? How can the distribution of matter in this area be so unusual? Is it possible that voids can group together? Is this pocket of space-time home to something strange such as massive amounts of dark energy, quantum anomalies, or something even more bizarre? The answer is that we simply don’t know.

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That is all I have for you today, but the conversation continues across social media and in the comment sections below. Do you agree with today’s message? Am I mistaken about some detail? How can I better elaborate on this topic in the future? Feel free to share your perspective!

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Written By Nicholas Burk, Executive Board Member © 2019 Free Thought Initiative