A drawing of a woman in silhouette wearing headphones in front of planets and shooting stars.

Podcast

Stars Above Haleakalā

Haleakalā National Park, Natural Sounds and Night Skies Division

Join in a night sky program from your own backyard! The Stars Above Haleakalā podcast features topics about the night skies we all share and the connections we forge between our Earth, our Universe, and each other. Each podcast focuses on a particular astronomy event for families to enjoy while they tune in to learn a little more about what they're experiencing. Your adventure to the stars (and beyond!) starts here!

Episodes

Splitting Sunlight - The 2021 Summer Solstice

Open Transcript

Transcript

Aloha, kākou. It's Ranger Laurel again, back with another “Stars Above Haleakalā” podcast. Today's podcast is going to address the elephant in the room—the star that's such an obvious force in our lives that we often forget that it's a star at all. I'm talking, of course, about our sun.

As always, please be respectful of those around you when you listen to this. If you chose to listen to this in a public place, use headphones to avoid disrupting those around you. Remember to use Leave No Trace principles wherever you are, from your local playground to your national parks—leave wildlife and plants alone, pack out any trash that you bring in, and respect your fellow visitors.

This podcast is intended to be listened to on Sunday, June 20th, 2021. This particular day happens to be the summer solstice for the Northern Hemisphere, which is the longest day of the year. Of course you can listen to it any day, but if you haven't taken the time to sit out in the early morning or late afternoon, I highly encourage it. The sun rises every single day; by most standards it defines a day itself. It is both commonplace and significant—we turn towards it again and again, but rarely do we sit out to appreciate it. I'm here today to make the argument that it is very important to appreciate our Sun. While most folks think astronomy is something that can only happen at night, a huge amount of effort goes around the world in to solar astronomy and studying our Sun, which is good because it turns out the sun is a lot more than a blinding disc in our sky. I could do a whole podcast series just about our sun, but that's a lot of ground to cover (93 million miles, to be precise). So to start things off, I want to talk about the obvious thing that our sun provides us, because it turns out that this simple thing is much more complicated than we ever could have guessed: sunlight.

[Introduction music]

We humans have known from time immemorial that light is hard to define but crucially important. Light drives in the broadest sense our ecosystems, economies, and cultures. But for a long time we struggled to unravel its mysteries. But let's start with the basics, first.

Your garden variety sunlight, the sunlight you're hopefully enjoying right now, is white light. The first thing that makes light tricky is how it gets different colors. For example, we all know that if you mix paint together, like red paint and blue paint, you mix them together, you get purple. If you mix in some green with that purple, you'll start to get a weird mud color. We all know the more colors of paint you add, the darker and muddier your end result will be. Light is the opposite. Mixing together all the colors of light creates white light, not darkness. This is called additive color mixing, and it has no bearing on what we're going to talk about today so don't worry about remembering it. Just know that white light is the combination of all colors. If you're interested in learning more about additive color mixing, you can look it up. It's pretty cool.

The point of this color mixing experiment is this: white light, can be helpful, but its often too much. When science really began digging in to sunlight was when we began splitting the sunlight into its spectrum. What exactly is its spectrum? That answer is easy. In this instance, spectrum is just a fancy word for “rainbow.” You're gonna hear me use those two words pretty much interchangeable throughout the course of this podcast. And that's where our story gets interesting.

Rainbows may be kinda sappy or cliché, but they’re also extremely interesting for scientists. In the simplest terms, rainbows are light broken down into its visible component parts. Most of us know that a rainbow is something we might see in an odd reflection, or arcing overhead after a rainstorm. Most of us also probably know that the rainbow goes from red all the way through violet. . A rainbow is a pretty, corny, pretty corny thing. So if I were to hand you a prism to cast a rainbow, and tell you to use it to divulge the deepest secrets of the universe, you might consider that an impossible task.

But believe it or not, the humble rainbow, a product of split sunlight, was actually the key to cracking significant astrophysical challenges. From the rainbow, we are able to identify the atomic makeup of stars billions of miles away. We developed technology so essential to our lives today that you’ll find it in your dentist’s office. In fact, we began to better understand the fabric of space-time itself. Think you can do that all with a rainbow, sunlight split six ways through a prism? Sounds like an impossible task. But our world is all about impossible tasks. So let’s dive in. [Brief static.] Laurel: TEst... Okay, um, so could you tell me your version of the Māui story? Kuaola: Okay. So long ago, the sun traveled much too quickly across they sky. Sara: It moved way too quickly. Chris: And one of the things that is a consequence of this is that Hina, the mother of Māui, isnʻt able to dry her kapa cloth. Kuaola: Drying is an important part of the kapa making process, so, making things difficult. Chris: And, so, Māui wants to right this so he goes to the top of the Haleakalā. Kuaola: Climbed all the way to the top of Haleakalā. And with one foot on Puʻukolekole, which is not the site of the Haleakalā Obervatories, and his other foot the top of Hanakoʻopiʻi, and their two miles apart, he stood atop the mountain and thatʻs where he snared the sun. Sara: Māui used rope to snare the sun at the top, and hold it in place. Um... they had a long conversation about it... Chris: and he convinces the sun that he should slow down. Sara: Other version say that he actually ripped off some of the sun's rays, in order to make the sun move slower, and it all just depends who's telling they story whether or not he ripped off those rays. Chris: And because of this, that's why we have the days that we have, the heat that we have, and the people were able to do all the work they needed to do. Hina and the people in Hawaii were able to dry their kapa cloth. Laurel: Great, that's perfect! Thank you so much!

[Music builds.]

The story about Māui is an important one for Haleakalā. After all, according to the story, right here on our crater edge is where he came to accomplish his feat—a seemingly impossible task to slow the sun's movement through the sky. You could ask anyone on the island of Maui to tell you the story, and you would get a different version every time. But one thing is always true: he will always attempt to snare the Sun, and he will succeed. In a way, you have Māui to thank for today of all days—he snared the sun, convinced it to slow down, and that brings us to the longest day of the year, our summer solstice.

For the longest time, the Sun was an inscrutable force in our lives. Early solar astronomers rigged projections of the sun, just to be able to make out any details on what appeared to be the sun’s surface without blinding themselves. And today there is a network of solar telescopes trained on the sun around the world. We have come a long way to see past the glare and begin to study our closest star in earnest. However, we still contest with significant challenges.

[Music notes]

One of the most advanced solar telescopes is the world sits next door to Haleakalā National Park. The Daniel K. Inouye Solar Telescope has taken some of the most detailed photos of the sun to date. It works its magic with a mirror that’s 4 meters--that’s 12 feet—wide. Plenty of telescopes have components that are larger than this, but the subject matter for the Inouye telescope presents unique issues. Remember how the kid in your recess (maybe it was you) used a magnifying glass to focus sunlight and set paper on fire? The lens of that magnifying glass that was hot enough to ignite paper was maybe two or three inches across. Now imagine the intensity of sunlight being captured by a mirror 12 feet across. That is some serious heat.

In order to combat the intense power of its subject, the Inouye includes a variety of cooling methods and safeguards. The telescope was designed with seven miles of pipe running through the observatory that deliver coolant to the system. The various mirrors themselves are also cooled, and a specially chilled metal donut eliminates about 95% of the heat from the incoming sunlight, before it affects the system. That’s a lot of engineering dedicated to beating the heat, and the painstaking research that goes into these cooling logistics is what makes the telescope operational. Today, we have it down to a reasonable science, but it hasn’t always been that way.

This problem of heat has plagued solar astronomers for as long as they've been pointing telescopes at the sun. So we're going to step back from the Inouye for now, and instead look back in time, and the very start of solar astronomy.

[Music break.]

OKay, so: The year is 1800, and astronomer William Herschel is confronting a safety issue. While the rest of Herschel’s astronomy colleagues are obsessed with creating star charts to improve navigation, Herschel has been nursing a fascination with our Sun. He faces a similar conundrum as the Inouye solar telescope—how do you study something that puts off such intense energy that it can crack the mirrors of your instruments and permanently blind you? Herschel begins experimenting with different colored glass filters, hoping to find one that reduces the intensity of the light and heat being focused by his telescope.

He comes to the conclusion that different colors transmit heat and light differently. For instance, red tinted glass stopped the glare but cast intense heat on the viewer’s eye—not ideal. By contrast, green glass stayed cool but allowed too much light through to be a viable telescope. This intrigued Herschel, and he set about designing an experiment to test the temperatures of different shades of light. And this is where that famous rainbow comes in: using a prism in a window to split the sunlight into the color spectrum, Herschel set about testing the temperatures of the rainbow, one color at a time.

As Herschel moved his thermometer along the spectrum, from one sliver of color to another, he noted something that seems obvious now: the light towards one the end of the spectrum—violet and blue—was the coolest in terms of temperature, and as he slowly moved the thermometer up the rainbow, the temperature steadily increased. Red light—on the opposite end of the spectrum, was the hottest. Herschel repeated this experiment a couple of times, and began using a secondary control thermometer, to make sure he wasn’t just documenting the rising ambient temperature of the room. Comparing his rainbow results against his control thermometer proved his theory that different colors of lights are associated with different degrees of heat. But what was truly groundbreaking about this experiment was a serendipitous moment after the initial experiment was done. After documenting the rising temperatures of the rainbow colors, on a whim Herschel moved the thermometer one more step up the spectrum—out of the red light and into what appeared to Herschel to be simply the darkness of the room. To Herschel’s amazement, the mercury in the thermometer continued to climb, as if some invisible heat source, even more intense than the red light, acted on it in a way he could not see.

In fact, Herschel had just discovered what we now know of as “infrared” light—light that we cannot see, but which acts upon our world in significant ways as heat. This story marks an historic moment in the study of light, heat, and the eventual discovery of the electromagnetic spectrum, which today drives much of our understanding of our world and the greater universe. This idea—that there is light that is invisible to us—is what eventually leads to the discovery of ultraviolet light, which I hope you are protecting yourself from as you sit out in the sun. It establishes the spectrum that runs all the way from radio waves to gamma waves: in truth, that beautiful rainbow from a prism represents only the tiniest section of the actual “light” out there. Everything from radio communication to x-rays became possible, when Herschel moves the thermometer into the dark unknown next to red light and revealed the unseen yet omnipresent nature of energy.

But when Herschel made this discovery, people struggled to accept the implications—how can you study something you can’t see or hear, or even barely feel? How can light be invisible to us? It was too mindblowing, and at the time it led to extremely flawed conclusions about the natural world. Much of the success of the scientific process depends on being willing to let go of assumptions when confronted by unyielding evidence, and that willingness can sometime take a little while to develop. Herschel’s discovery was a baby step, a challenging but necessary one.

[Music notes]

The resulting fixation on prisms and rainbows, however, would lend itself to another important discovery, which molds astronomy to this day. Around the same time that Herschel is understanding the infrared and invisible light of our Sun, other scientists are noticing bizarre anomalies in the sunlight's spectrum itself. Joseph von Fraunhofer, a young glassmaker, could not shake a particular feature of the rainbow: with a good enough prism, within the split sunlight he could identify vertical black lines, shadows, interspersed at random through the smooth continuum of one color to the next. You can picture, like, a rainbow barcode, stretching again from violet to red, with black lines of varying widths interspersed throughout. Fraunhofer meticulously documented the placement of these lines, and realized no matter the prism, no matter the day, the sunlight split into the same pattern without fail. With a good enough prism, you can see these lines, known as Fraunhofer lines, to this day. What was more curious, using specialized glass more precise than a prism, he could split the light from distant stars as well—and the resulting rainbows of those stars also had these mysterious black lines, some that matched those of the Sun, and some that landed in very different spots. Different stars had different barcodes. [Music building] Like Herschel’s infrared discovery, understanding the significance of these lines took decades of experimentation and discussion. Pursuing the relationship between color, spectra, Fraunhofer Lines and energy, scientists realized that established elements, like sodium and copper, caused flames to turn different colors when they were burned. Returning to our friend the prism, enterprising scientists vaporized various elements, and split the resulting colored firelight through a prism, and discovered a bizarre and exciting inverse of the sunlight spectrum: instead of a complete rainbow with dark bars, elements vaporized in flames exhibited a dark spectra with a few brightly colored bars interspersed throughout—a sliver of teal, some ways away from a strip of scarlet. In essence, each element, when heated to a gas, emits light that can be split through a prism to reveal a unique “fingerprint” of colored lines. Hydrogen has a unique set of colored lines; sodium has a different set, and copper does too.

Well, it didn’t take long to put two and two together: the bright bars present in the spectra of the elements line up with the dark bars in the spectrum of sunlight. Scientists realized that every element will absorb its particular slivers in a continuous spectrum. All of these Fraunhofer Lines that we detect in sunlight’s spectrum are actually giving away the elements that are vaporized around the sun—by matching up the elements bright lines against sunlight’s dark lines, we can identify each element present in our sun.

The physics of this get complicated very quickly, and the rules that dictate these particular reactions, are part of Kirchoffʻs Rules, are worth a look if you’re wanting to take a deep dive into how this works and how we know.

THe bottom line is this is the beginning of a field called spectroscopy (say that five times fast), studying the absorption and emitting spectra of elements to delve into chemical realities. [music building] What is so crucial about this discovery of sunlight barcodes and elemental keys is that the only thing we needed to be able to understand the components of far-off space stuff is light, which is very good at crossing the great expanse of our universe. If we can see it, we can understand what it is made of.

Using spectroscopy, we now know that the element gold is present in trace amounts the atmosphere of our sun, in a vaporized form, because we see the shadows of gold's known barcode present in our split sunlight. And if you have ever wondered how we know what kinds of elements are out there—how can we prove that stars throughout our galaxy are made up of hydrogen, considering we have never visited a star, never mind gotten close enough to one to sample its chemical composition—this is how. Spectroscopy, the harnessing of spectra, light, and shadow, to unlock our Universe. Tell your friends. And thank your nearest rainbow.

[Music crescendos.]

I sometimes... often, wonder how people way in the future will perceive our “breakthroughs.” Like, waaaay in the future, what will we make of these moments? I think about what makes Māui a myth, and Herschel a scientist, and I wonder if time plays more of a roll than we realize. I think about our descendants telling of the legend, “How Herschel Split the Sun,” ages from now, maybe as we bask in the light of a remote star as intergalactic travelers. That sounds ridiculous,like too far off, and impossible. But in the bright light of day, I find that “impossible” turns out to be a relative term. [Music notes.] I hope you can forgive me for finding solace in our myths about tackling impossible problems. I think I'm drawn to these stories because as a park ranger and a citizen of this Earth, I realize I am in the thick of a lot of impossible-seeming problems. Here in Hawaiʻi, we battle the extinction of unique species at an accelerating rate. We see smoke drift over, all the way from California, and we watch our coral reefs lose their rainbow of colors, bleaching to a ghostly pale as ocean temperatures warm. Climate change feels like an impossible problem, a mountain that keeps piling on—where is our Māui, to set things right again?

Well, Māui may have been demigod, but it was his actions and deed, rather than his superpowers, that we tell each other about today. With that in mind, anyone of us can feel empowered to take action for the things that matter: to stand up for our communities, find creative solutions, think through impossible tasks. Same as Herschel, who wanted to stare at the sun. Herschel died well before anyone thought they could create a telescope like the Inouye for solar observation, but the two live on the same continuum of baby steps, and sharing what we know.

This story does not end in the past with a clean resolution or on some distant summit far from your grasp. Every one of us can experience the everyday phenomenon of sunlight, the heat it provides or the light it offers, and what's more, thanks to the electromagnetic spectrum that Herschel revealed, we share our experiences like never before. So here's what I'm thinking:

If you have a true prism at home with you, that's awesome. With a few other supplies and equipment, you can repeat the experiment conducted by Hershel to discover infrared light. However, you don’t need a true prism to get a sense of the rainbows inherent in sunlight or to see the sliver of the electromagnetic spectrum we call visible light. You can make a rainbow with the mist of a hose, a drinking glass filled with water, or even a CD (if you remember what those are). As long as the sun isn't too high in the sky, you can catch the sunlight at the right angle and create a rainbow and show it off. In fact, I want to see a rainbow of rainbows, folks, so get ʻgrammin. Take a moment today, with all this extra sunlight on our summer solstice, to find some rainbows and take a photo to share with the world. Pretty sappy, right? Well, I think I'll lean into it, so when you share your photo and tag it #sappyrainbowphoto on social media, along with #HaleakalaNationalPark, so we can all enjoy the rainbows out there. And just a heads up, we might share some of your photos on our Haleakalā NP pages for everyone else to enjoy.

If rainbows are corny or sappy or sentimental, so be it. The universe can be much worse things, and after enduring such long dark nights in the past I have no problem whatsoever taking a few minutes to let the sun shine, appreciating the simplest of wonders, and marveling at something as simple as split sunlight. [Music building, continuing under:] Today’s podcast was a production of Haleakalā National Park, written and narrated by myself, Laurel McKenzie. Special thanks to Rangers Kuaola Raymond, Sara Peyton, and Chris Petruccelli for helping me tell the Māui story. The podcast graphic was designed by Katie Matthew. A big mahalo, thank you, from me to all you listeners who tuned in on what was hopefully a sunny solstice day. For more information on Haleakalā National Park, the various resources we protect, and how to submit take and share your sappy rainbow picture, visit www.nps.gov/hale, or drop us an email at hale_interpreation@nps.gov. Until next time, enjoy the new day, and happy rainbow hunting. Aloha. [Music fades out.]

What comes to mind when you think of summer? Our long days and short nights around the summer solstice may mean less time for stargazing, but there are secrets to unlock even in our Sun!

Join Ranger Laurel on a crash course adventure through solar astronomy. Hear about the legends we tell, the science behind our knowledge, and the data of our universe locked up in something as simple as a beam of sunlight.

Gifts of the Geminids - The 2020 Geminids Meteor Shower

Open Transcript

Transcript

Aloha, kākou. Hello, everyone.

Welcome to Gifts of the Geminids from Haleakalā National Park. I'm Ranger Laurel. Today, I'm going to be sharing with you a little bit about the how and the why of meteor showers, and in particular, the Geminids. It is December, which is a season for giving and gifts, and so it seems fitting to me that when we watch the meteor shower tonight, we'll explore some of the unique gifts that the Geminids can provide for us.

A few quick reminders before we dive in. If you are listening at Haleakalā National Park, or in any other protected or natural area, please use headphones or earbuds to listen to this program, so you don't disturb others around you or the wildlife. And also keep in mind social distancing guidelines. I know we're all very used to hearing it now, but please avoid crowding, if you're out in a public space have a face covering ready in case you can't maintain that social distancing. Above all, just respect your surroundings and be kind to your fellow stargazers.

This program has been recorded with the intention that you will hear it the evening of Sunday, December 13, 2020, which is the night of the Geminids Meteor Shower. I'll be making references to this particular day in time, and this particular meteor shower. However, if you happen to be joining us from another place, or another time, and you're interested in hearing a little bit about... the end of the world, the patterns that define us through time, what the future hold, maybe... stick around. Because we're happy to have you go on this journey us.

[Music--piano that leads into synth melody.]

I'm going to start tonight off with a question. And just a heads up, this is not how I usually work. I usually have my audience directly in front of me, in person, and we share and learn in a very collaborative way. However, tonight is a little different, but I don't want to give up on asking questions, because I think questions are really important ways for us to learn and connect with the world around us. And I know this question will probably strike most of us as a little heavy, especially given the year that we've had. But maybe this is a benefit to us not being in person, and having a little bit of space. Because I am not in front of you, you don't have to feel pressured to answer in any particular way, or at all, really. You can just let the question wash over you. And if you don't like it, let it go. Let it drain away. But if you are willing, and interested, and want to engage in it, I want you to consider this:

"If you could go back in time to exactly one year ago today, what is one thing you would tell your past self?"

And I'll repeat it...

"If you could go back in time to exactly one year ago today, that would be December 13, 2019... what is one thing you would tell your past self?"

Woof, right? I bet we'd all write novels to our past selves, if we could. Silly stuff, like "stock up on toilet paper and flour." Or frustrating stuff, like "now is the time to take that trip you've always wanted to take." Or even sad stuff, like "don't keep telling yourself you'll visit your relatives next month." Lots and lots of stuff. So many lessons learned, regrets, heartbreaks, struggles. I know what I would say. If I could talk to myself one year ago from today, I would say "be prepared to let things go." But I would also say, "you are about to find yourself blessed by some pretty incredible gifts."

No matter how you think about it, this year has not been easy, by any means. So why am I even asking about this? What does this have to do with a meteor shower? Well, it turns out that between meteor showers, a feeling that the end of the world is nigh, a sense of return or repetition, this Groundhogs day that we seem to be stuck in, there's a lot of common ground.

We'll get to that, but first, I do want to set you up for success, because I'm pretty sure most of you are here mainly for a meteor shower, and I just happen a distraction until it gets dark enough. So. Before we get too deep into the end of the world, I want to talk about good meteor shower watching. Which also happens to be the very first gift of the Geminids.

[Musical notes.]

Gift number one: front row seats.

[Musical notes.]

So like I promised, we're gonna talk about good meteor shower watching. There are some things you can control, and there are some things you can't. The biggest thing that tends to impact meteor shower watching is the moon cycle. On a full moon, stargazing is, let's just say, not ideal. Our moon is the second brightest thing in our sky, after our sun, so when meteor showers happen on full moons, it's just not the best viewing. But new moon nights, there is no moon out and there's no natural light pollution competition, so the meteors can really shine their best. Tonight, we're pretty lucky, we have a new moon. So given the new moon, and hopefully some good weather for you, which is unfortunately another thing that you cannot control, you should have a pretty decent view of this meteor shower, right off the bat.

As far as things you can control, when it comes to optimal meteor shower viewing. Look around your surroundings for light pollution. You might be able to ask your neighbors to please turn off their blinding security lights next door--I don't know, kinda depends on your relationship with your neighbor. Do you have security lights that you can turn off? Did you leave lamps on inside that you can dim? How 'bout the flashlight that you brought out with you? Is that off? Is your phone? You can listen to this podcast without scrolling on your phone, I promise. All of these things are important for making sure that you can have a good meteor shower experience. So turn down the brightness on your phone, or your tablet, or your screen, or whatever, and put it away, and resist the impulse to check your screens.

If you need motivation, think of it this way. The human eye, in general, can take up take about half an hour to adjust to darkness, about thirty minutes. Luckily for you, this program is about half an hour, so the timer starts now. If you can keep your devices tucked away for thirty minutes, you will have a nice meteor shower.

Finally, you can control in the night sky where you look, and a lot of folks might think that that is the key to seeing the most meteors. However, I'm gonna say, "don't bother." The Geminids, like everyone meteor shower, is named after the constellation from which it appears to radiate. "Geminids" literally means "Children of Gemini," so in this case we're talking about the constellation Gemini. But all that really means is when you see meteors tonight, you could trace them back to the constellation Gemini. But by no means should you fixate only that constellation because the truth of the matter is meteors can and will appear throughout the entire sky. So gift number one of the Geminids: don't stress about the right place to see them. Wherever you are, you have front row seats. So sit back, relax, because now we're going to talk about the end of the world. Bum bum bum...

[Music notes.]

Gift number two: tomorrow

[Music notes.]

So, for thousands of years, humans have been watching meteors and meteor showers. A meteor is really just a shooting star, it's that bright flash of light streaking across the night sky. Often, they've signified the end of the world. A particularly infamous meteor shower occurred in 1833, during the Leonids, which is an annual November shower, but in this year, 1833, there was such an intensity to the shower that people who were watching thought the world was surely ending. It didn't, obviously, but it made a lasting impression on those Northern Hemisphere observers. Likewise, in native Hawaiian traditions, astronomical events could be foreboding, or they signify significant things to come. Certainly meteor showers stand out, but up until recently it was more because of the doom and gloom, a sense of anxiety and bad things to come rather than the pretty sparkly stars that we're watching tonight.

So what is a meteor shower, exactly?

You could see a shooting star on any random night, if you happen to be looking at the right place at the right time. However during the many annual major meteor showers that pepper our skies, for one or two nights at a time you don't have to be so lucky. Depending on where you are and the darkness of your particular sky, you could see close to a hundred or more meteors fall over the course of just one hour. How do I know that? Well I looked it up on a bunch of astronomy websites. How do the astronomers know that tonight, on all nights, and reliably the same night every year, we can brave the cold to watch the Children of Gemini light up the night sky?

Well, it all comes down to our place in the solar system.

[Music notes.]

Picture Earth's orbit. It's an approximate circle around our sun, and this is our annual orbit. It defines a year for us, one year. Around and around and around we go on this disc, following the same path and because we do this we occupy the same space on the same day, year after year after year. Now, imagine a dust cloud smack dab in the middle of that path, just somewhere in our orbit. It's not an enormous dust cloud, nor is it catastrophic, but it does take us a few days to move through it. So as our earth moves through this particular dust cloud, which we encounter in the same place, every year, some of that dust and debris enters out atmosphere. These particles heat up as they careen towards earth; eventually friction ignites a trail of air behind the particle and this is what causes that brilliant streak of light we call meteors, which quickly disintegrate back into the darkness of the sky.

Another way to think about is like on a long highway road trip. So most of the drive is clear, but for five minutes you drive a big cloud of bugs. So the meteors we see during a meteor shower are like the gnats, hitting the windshield... which is not entirely appetizing, but there you have it. Now whenever you see a meteor, you can think of a smushed bug, on your car... great.

Take heart in the fact that unlike the bugs on our windshield, there's almost never anything left of a meteor once it makes its dramatic appearance. Now might be a good time for a little bit of space vocabulary--a meteor is just the thing that we see lighting up the night sky, that shooting star. A meteorite is something that survives the atmosphere, and makes it all the way down to our surface. So folks might think that during meteor showers, there's a higher incidence of meteorite. Right? That kinda makes sense, because that's when more things are falling through our atmosphere, so wouldn't we find more things on our surface. However, there's no correlation between the two. Just because we have a meteor shower, doesn't mean you are going to get hit in the head by a space rock.

And the reason for that is all around you on the ground. Look at whatever you're sitting on, standing, might be dirt, might be pebbles, gravel, sand. All of these things--that little rock, that big grain of sand--are about the same size as what makes up your average meteor, which is pretty incredible given just how bright they are when they shoot through our atmosphere. Though they be but little they are fierce, and their entry puts on quite a show.

So here we are tonight, of all nights, sailing through a dust cloud, which is super romantic. It's the same dust cloud that we sailed through last year, and it'll be the same one that we encounter pretty much exactly one year from now. So where or where did this dust cloud come from?

You'll remember that I mentioned that not too long ago, hundred years ago, maybe a little bit more, meteor showers were mainly taken as a sign that the world was about to end. But of course, in our modern era, we know that's all just speculation, right? Knowing what we know today, there's no relationship between meteors, and the end of the world... right?

Well... the truth is, meteor showers are kinda evidence of the opposite. Instead of signifying that the world is about to end, they are a good reminder to us that while we may feel kinda unlucky sometimes, life actually could have been a whole lot worse... or even ceased to exist a long, long time ago.

[Music notes.]

To explain it, let's go back to our image of Earth's orbit. Imagine watching the year go by, from the bird's eye view above our solar system. Earth is spinning along, it passes through the dust cloud of the Geminids meteor shower without a problem and continues on. But while we, Earth, are somewhere else in our orbit, something big, something rocky, something very bizarre is making its way from beyond Mars and into our neighborhood, leaving behind a trail of dust. What just happened? Well that was an asteroid that crossed our path.

Let's put this into perspective. Meteor showers are the result of space dust entering our atmosphere. They don't really pose a risk to us, as their material is tiny. However, the source of that material is an entirely different story. We can all remember a famous example of when an asteroid actually made it to Earth--think of the dinosaurs. And yet, we just watched in our imaginary Earth's orbit, an asteroid that passed us by. It zipped in, close to the Sun, left that trail of dust scattered across our orbit, and then went on its merry way. I'm very glad we weren't home for that, but it's a good reminder that hazards can zoom out of nowhere. In this particular case, this big, beautiful, beloved hazard is an asteroid known as 3200 Phaethon, which I'm just gonna shorten to Phaethon for now.

So. Gift number two from our lovely Geminids? They remind us every year that life could have been a whole lot worse. In fact, every single trail of dust we encounter for every single sparkly meteor showering throughout the year serves as a reminder that the Universe is kind of a dicey place. In fact, don't get super worked up about this, but the asteroid, Phaethon, parent body of the Geminids, is considered a PHA, which is just a fancy way to say "potentially hazardous asteroid." Uhg, right? That is the last thing we need right now.

The good news is that Phaethon is good ol' reliable. Its path is extremely well documented as it rockets near our sun, and us, and back out into the reaches of the asteroid belt. Earth is rarely nearby when Phaethon crosses our orbit. Its latest near swing near Earth was in 2017, three years ago, and it won't be back in our neighborhood until 2093. So I think we're good... at least for a little while.

Before we go any further with Phaethon, I do feel like I should throw in a quick space disclaimer. If I were to talk about any other major meteor shower, I probably shouldn't even be mentioning the word "asteroid." Asteroids are rarely the source of our meteor shower dust streams. Typically, it's comets that leave behind the ideal debris for these kinds of events. For example, the Orionids, in October, are the result of the most infamous comet of all, Halley's Comet. Comets are rocky snowballs, wandering bodies that are composed of ice and dust. It's the ice, vaporizing as it approaches the sun, that gives a comet its tail. Asteroids are not icy. Instead, they're composed of rock and metal. Without the volatile icy debris, asteroids are not typically considered to be good candidates for creating meteor showers. But Phaethon is no ordinary asteroid.

While we've been observing the Geminids for centuries, the parent body Phaethon was only discovered in the '80s. That's 1980s. It still proves to be mysterious. It's a plucky little asteroid that could. When it crosses our path, it manages somehow to leave behind quite a bit of debris for us to orbit through. Scientists are not entirely sure what Phaethon's complete backstory is. Perhaps it once was a comet but was long ago stripped away of its ice, but it still continues its usual orbit. Perhaps its incredibly close encounters with the sun causes it to dry and crack enough to deposit those debris. Perhaps there's a really good reason as to why it's blue in color, and not red, or gray, as asteroids normally are. The answers are out there, but for now we're not able to find them. We just get to watch the annual byproduct of this eccentric solar system resident and wonder and wait... until 2093.

[Music--piano that leads into a synth melody.]

So that's the long and the short of our meteor showers. Unfortunately, like a lot of the things going on right now, the realities of distant asteroids and solar system debris... while they can impact our lives, they're just out of our control. There's nothing we can do about them. We’re just passengers in this planet, spinning along, weathering the space dust from day to day, year to year. A lot of the time, we may feel pretty helpless. But there is one last gift of the Geminids that I want to share with you.

[Music notes.]

Gift number three: a bucketful of sand.

[Music note.]

I feel pretty confident that next year, we will see the Geminids meteor shower. This year has taught me a lot about what I should and can expect from the world. Certainly, much fewer things are a given than I would have thought. At the start of this program, I asked you to think about what you would tell your past self from one year ago. That was just a rhetorical question. There are no actions you can take to communicate with your past self, obviously, even though that might be pretty satisfying.

Instead... I want you to start thinking about what you would tell your future self. What might you want your future self to know on the eve of the next Geminids shower, 2021?

While I am confident that we will see the Geminids next year, one day, of course, the Geminids will peter out. It's happened before, to other meteor showers. The parent body ceases to cross our path, the debris are eventually scattered, or incinerated. Observations from the 1800s tell us about fantastic meteor showers that have just faded into oblivion. All things change including space, though often on a scale that we struggle to recognize.

One day, though hopefully not any time soon, Phaethon might scoot just a little bit too close to that sun and rejoin the heart of the stars and be gone forever. Or, the asteroid might even make good on its namesake. For those of you who maybe aren't as familiar with Greek mythology, Phaethon is the child of Helios, and Helios is the god of the Sun. As a teenager, Phaethon wanted to drive his father's flaming chariot, which was the Sun... it ended poorly, and Phaethon ended up crashing into the Earth. Sometimes astronomers have a really uncomfortable, albeit well-read sense of humor. Thank you, astronomers.

In spite of the chaos that tends to permeate our Universe, we humans seem to make a really good habit out of finding patterns across space and time. For example, certainly one good change is the fact that we can now enjoy meteor showers without fearing the end of the world. Because we have studied them, researched them, figured things out, we know that when we see a meteor shower, we don't have to worry, like I said, about getting hit on the head by a space rock. We don't have to worry about a vengeful god. Instead, we can look up and see meteor and make a wish... which is pretty nice.

But humans can't easily shake our obsession with doom and gloom. Sometimes I wonder what it must have been like to step outside under those Leonids in 1833 and feel, in the pit of my stomach, that sense of dread of the end of the world. And then I remember that we have just figured new ways to instill that sense of dread in our society. So maybe in our modern world, we look for other places for signs that things are going wrong. Like nowadays, the newspaper headlines and the social media feeds might strike the same sense of fear or anxiety that a meteor shower once did centuries ago. Its funny things can change, but somehow stay pretty familiar.

The day for Phaethon's end is, inevitably, one day, but I really really really don't think it will be tomorrow or the next day or even the next century. The tricky thing about doom and gloom is while we might be tempted to look toward the end of our planet, our Universe, or even just our lives, and throw up our hands and say "what does it matter, if it all comes to an end?" I would urge to reconsider.

If the Geminids give us anything it is proof that something does not have to permanent to be meaningful. That fleeting moments can make the most difference. Gift number three of the Geminids: something as insignificant as a bucketful of space junk sprinkled across our upper atmosphere can put on a show, quite possibly at a time when we need it most--in the dead of winter, darkness, and complacency.

The Geminids tell us there is promise, even in these fleeting moments. There is hope, even in impermanence.

My work as a park ranger at Haleakalā National Park gives me all the more reason for that hope. Every day, I talk with people who are invested in the wellbeing of the endangered species we protect and the Hawaiian culture we preserve. Volcanologists will tell us that the island of Maui, where Haleakalā is located, follows in teh footsteps of its other Hawaiian island siblings, like Oʻahu and Kauai, and the islets and atolls that make up the rest of the Hawaiian islands. So this means that one day the island of Maui will experience renewed eruptive activity. Although probably not tomorrow, or the next day, or the next year. What's more, one day Haleakalā and the entire island of Maui will erode to the point where it sinks back below the surface and eventually subducts beneath the tectonic plates, to be melted down into the Earths' mantle. Altogether, it's just a fleeting speck of land, shooting across the ocean in a geologic timeframe.

Yet even though this destruction awaits us, not one of the impassioned visitors that I talk to every day believes that we should just give up. Instead, they tell me that they want to save our forest birds from extinction; that our sunrise vigil every morning is enough to protect the silverswords and a battle worth fight. The future is what we make of it today, now

So let's think about the future. Writing letters to our past selves--futile. We've already covered that. But writing letters to our future selves in an entirely different matter. Think of the Geminids as a bookmark in the year, a beautiful and simple moment to remind us to reflect on what these past twelve months have been for us. So for those of you who are interested, I would invite you to take the time, sit down, find a moment, and write a letter to yourself, to be opened one year from today, on the eve of next year's Geminids. It doesn't have to be a long letter, or profound, or even complete sentences. It can be how you've felt this past year, or what you're hoping for next year. It can be a favorite moment or a wish, or a sadness. It can be anything. But the catch is, you can't read it again until next year. Just in case that temptation is pretty strong, to read it before next year, or you're afraid you'll lose it or misplace it, I do want to help you out.

If you mail Haleakalā National Park your future self letter over the next few weeks, we'll hang on to it. We won't read it, I promise. We'll just keep it safe and sound and mail it back to you on December 1, 2021, so you can read it during the Geminids meteor shower next year. The park's address is in the descriptions of this podcast, along with a little bit more information on how to send in your letter. Chance are, you'll probably forget that you even wrote a letter until sometime mid-December next year when you get some mail from yourself, which I happen to think would be pretty cool.

The Geminids are definitely a gift that keep on giving.

[Music notes.]

Up to this very moment, Earth lives on. We have avoided complete destruction, asteroids or otherwise. We're just one plucky little planet in the backwaters of a galaxy, which drifts among the thousands of galaxies of our Universe. In the grand scheme of things, you and I, we're just grains of sand. But never, in the grand scheme of things, forget the agency you have to make a difference.

As you watch the meteor shower tonight, as this podcast fades out and you're left with the night sky to enjoy, think about those meteors that you see streaking across the sky. And remember how extremely small those meteors actually are. Just grains of sand, like us. And if you feel so compelled, maybe as you write your letter, think about how would you like to light up the world in that way? And ask yourself, what gifts will you give, to our future generations, who sit down next year, or next century, to watch the Geminids light up the sky?

[Music interlude. Music plays over the final segment.]

Tonight's podcast was a production of Haleakala National Park, written and narrated by myself, Laurel McKenzie. The podcast graphic was designed by Katie Matthew. Special thanks to the Interpretation Division and park management for helping this become a reality. And a huge thank you to all of you listeners out there, who tuned in for a new kind of night sky program. As I always say to visitors in the park, it's because of folks like you, who show up, and have an interest in this kind of stuff, that I get to have the absolute best job in the world. So a big mahalo, a big thank you, from me to you.

For more information on Haleakalā National Park, the various resources we protect, like our night skies, which are awesome, and how to submit your Geminids letter for safe keeping to the park, you can visit our website at www.nps.gov/hale, that's the first four letters of the park name Haleakalā. That's www.nps.gov/hale. Or you can drop us an email at hale_interpretation@nps.gov.

Join Haleakalā National Park for a virtual night sky program and dive into the science and significance of the Geminids. Learn about the origins of these cosmic spectacles, and gain a better appreciation for what these events can mean for us today.

Learn how to submit your Geminids 2021 letter: www.nps.gov/hale/learn/photosmultimedia/gifts-of-the-geminids-podcast.htm