Title: Mapping the Stars

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Brian Lehrer: Brian Lehrer on WNYC. One quick program note before we do our last segment of today, which I think is going to be really fun. You can tune in tonight at 7:00 here on the station, or if you have New York 1 on Spectrum cable, turn on your television, and you can see me and two other moderators moderate the Democratic primary debate for New York City comptroller.

That's tonight at seven o'clock. In addition to breaking down the results of the New Jersey primary on tomorrow's show, which we were just talking about, we will also play excerpts from and have analysis of that comptroller's debate. Tune in for it live tonight at 7:00 or tomorrow morning when we're playing excerpts and taking your reactions. All right. Now, if you've ever looked up at the night sky and wondered where we are, not just on Earth but in the galaxy, this one's for you.

Pedro Pascal: We are a product of cosmic encounters, and what's happening in the Milky Way Galaxy is happening throughout our galactic neighborhood and across the universe. I'm Pedro Pascal. Join me on a journey through our tight-knit stellar neighborhood into the bustling metropolis of the Milky Way.

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Brian Lehrer: Did you recognize that voice? Yes, he did identify himself. A new space show. It opened yesterday at the American Museum of Natural History's Hayden Planetarium, called Encounters in the Milky Way, takes audiences on a time-traveling journey through our galactic neighborhood. Narrated by Pedro Pascal, the show is powered by new data from the European Space Agency's Gaia Mission, which has mapped nearly 2 billion stars in our galaxy.

It's the first show in the Planetarium's 25-year history to be built around the concept of cosmic motion, not just the stars, but how our entire solar system is on the move through the Milky Way. Here's something remarkable. While creating visualizations for the show, scientists made a new discovery: a spiral structure in our own Oort cloud, I think it's called, like a miniature galaxy made of comets, hiding in plain sight.

Joining us now, we are so happy to have Jackie Faherty, Dr. Jackie Faherty, astrophysicist, science educator at the American Museum of Natural History, and curator of Encounters in the Milky Way. Dr. Faherty, welcome back to WNYC. Thank you so much for joining our show again.

Dr. Jackie Faherty: Hi, Brian. Yes, I love coming on your show, and hopefully, this is a happy conversation. Lots of good stuff to talk about, about the cosmos.

Brian Lehrer: Indeed. Listeners, here's your chance to talk to a real-life astrophysicist as well. Have you ever looked up at the stars and wondered where we are in the galaxy or how far we've traveled through space? Give us a call. 212-433-WNYC. What do you want to know about the Milky Way, about space travel, about what's out there, or Encounters in the Milky Way at The Hayden Planetarium? 212-433-9692. Call or text. To start, take us inside the show. What will audiences see and experience in Encounters in the Milky Way that's never been done before at the Planetarium?

Dr. Jackie Faherty: Yes, this is a special show. I think it's a special show to me, especially because it's something that I've been kind of working on with audiences for a couple of years. If you've ever come to a Hayden Planetarium Astronomy Live program, you know that we bring in new data sets, data sets straight from academic journal papers and tell people these stories of what the academics are working on that's really relevant to you, to your understanding of the place in the universe that you live.

We really came up with this story that takes you from the things that you encounter because you're in motion in the solar system, to the things that have probably impacted you and you didn't realize it over the course of the journey. Our solar system has been on over several billion years. We start in the solar system, and then we move you a little farther away to our solar neighborhood, where you can meet our neighbors, our stellar neighbors, and then some neighbors that are coming for you, and you didn't know it.

We're in motion. We're going to have this amazing encounter with another star in roughly 1.3 million years. We actually simulate that for the first time in this space show, and what will happen when we encounter each other, and then we pull you farther away, and we show you your galactic environment that you're in. Most people don't realize but we are inside of something called a local bubble.

Just like Little Red Riding Hood, skipping through the forest, the Sun in our solar system, moving around, walked into this area that gives us this gorgeous view of the Milky Way, and then we take you outside of the galaxy, and we show you this encounter that has been going on for several billions of years as the Milky Way is eating this other galaxy called the Sagittarius Dwarf Galaxy, and it's creating this gorgeous cascade of stars around us.

Each time it passes around us, it sends a wave of energy in that drives star formation, and we were born in an era in one of the first passages of this galaxy, and we bookend this show with gorgeous imagery of two telescopes: the European Space Agency's Gaia Telescope, which gave us this map, and NASA's James Webb Space Telescope, that's this boutique awesome telescope that's giving us close-up views of other galaxies that are out there, of other worlds that are reminiscent of what we're mapping of our own from the inside out. You get all of that in one 25-minute experience in the Planetarium.

Brian Lehrer: That's a lot for 25 billions of miles, billions of stars. One of the big themes I'm hearing you is motion, stars, planets, entire systems moving through space. Why is that important for us to understand? Especially since from Earth, the stars appear so fixed.

Dr. Jackie Faherty: Yes, they do, and I think that, like right as we're talking, the Earth's moving around the Sun, and every second, we clear about 30km. That's how fast we're moving, but the solar system and its motion around the galaxy is clearing about 200km every second. This constant motion means that you're not going to stay in the same galactic area. Everywhere that you move around the galaxy, the environment changes, and you can get impacted by that.

The solar system can be impacted by that. You can move into an area where you get a little bit closer to another solar system, which would make it easier for you to study that other solar system. Now, unfortunately, Brian, for you and I, I don't even know your age, and you don't know mine, but we won't live long enough to see the kinds of changes that are happening because we don't live for long enough.

Our average lifetime is whatever 70 to 80 years depending if you're whatever gender that we're calling the lifetime. At the end of the day, scientists know far more. We know what we're going into because once we understand motion, we can actually turn the clock forward and show you the area of the galaxy you're headed for and how that might impact you. How it might impact you when you leave this bubble and get exposed to new amounts of radiation, our solar magnetic sphere will shrink a little, and we're going to get exposed again.

Our solar system will be, that's something for our great, great, great, great, great, great, great, great times a lot of exponents, grandchildren will be experiencing this, and I think it's important to always remember science takes you on these journeys. We know a lot. We can be very predictive with this, and this show brings you that.

Brian Lehrer: There's this moment in the show that visualizes our Sun's 230 million-year journey around the galaxy. What does it mean to say that the Sun is 20 galactic years old?

Dr. Jackie Faherty: Yes, that line has been resonating with a lot of people, that we think of ourselves or our solar system as, in some ways, that's your home. That's where you're from. You are from the solar system, and that solar system is also part of this larger structure. That's where it's from. It's from the Milky Way Galaxy. It formed in it. It formed as a result of the gas and the dust that got pulled together into this Milky Way, and we've been around for roughly 4.5 billion years.

That's how old our Sun is, and it takes us roughly 230 million years to go around the galaxy. The same way the Earth goes around the Sun in 365 days, and we give ourselves an age based on how many times we've gone around and around, and that means something to everybody. The solar system, your home, has the same idea, and we have gone around 20 times. We are 20 galactic years old. Take that for what it is. If that makes you feel young or old doesn't matter. It's just what you are.

Brian Lehrer: Roger in Maywood has a question. You're on WNYC. Roger, hi.

Roger: Good morning, Brian. I know that each star, including our Sun, has its own proper motion, aside from the general circular rotation of the galaxy, and I also believe that the Earth or our Sun and solar system can bob above and below the galactic plane, and I've heard discussions about how that might affect climate or might explain some of the shifts in climate over long periods of time. I'm wondering if you can speak to that.

Dr. Jackie Faherty: Yes, I'm happy to. You brought up a word that we don't have in the show, but I, in the Explainer guide, try and explain to people what proper motion is. Any kind of star, any kind of object in the galaxy, it has a three-dimensional motion. You have a motion in the X direction, the Y direction, and the Z direction, so up and down, left, right, side to side, all of that.

We call proper motion the motion that you can see across the sky. We actually demonstrate for you proper motion in this show. There's this gorgeous scene where we release the stars for you, and we keep you kind of located in one spot, and then off the stars go. You're seeing the way the stars move across the sky, but that's a motion that's basically two-dimensional.

You're asking about our three-dimensional motion, and that is true that our Sun in our 20-galactic-year-old solar system age does a little bobbing up and down, and this gets to the point I was making before. When you fast forward motion and you look at where in the galaxy you are, whether you're in one area versus another, it's going to expose you to different parts of radiation that will impact.

It trickles all the way down to climate on Earth. We think this is something that's a long-term study that we are doing based on our place in the galaxy, our pace in the galaxy, and all of this long-term data we have been collecting of what's happened on Earth. It's not just all the things that we're doing to our planet that can affect our climate. It can also be where you are in the galaxy that impacts you, and if you're above or below the plane, the radiation you get exposed to will differ.

Brian Lehrer: Jim in Huntington has a question. Jim, you're on WNYC with Dr. Jackie Faherty from the Hayden Planetarium on their new show. Hi.

Jim: Thank you, Brian, you've got a great show. Doctor, quick question. I understand that the theory is that from a singularity, the Big Bang occurred. We are now an expanding universe. I just read some piece in which some theorists believe that it's a recycling event. It expands. At some point, it'll begin to contract, restore itself to a singularity, and then over and over again. Your thoughts?

Dr. Jackie Faherty: Yes, that's a, that's real zinger to have one to give the thoughts on. It's such a hard concept as to what's happening in the long-term lifetime of the universe. Starting with the singularity, which is the pretty well accepted concept that we had this thing that we've called the Big Bang, and then once that occurred, you had an expansion period, and then the universe kind of comes to be over a series of billions of years.

What happens in this in-between of whether there's going to be some springback, how the universe is going to eventually evolve, and maybe even end, is highly and hotly debated amongst cosmologists and astronomers. We unfortunately don't have anything about that in this show. This show keeps you close to the Milky Way and close to home, but we have another show that's called The Dark Universe that explores these concepts.

That show, actually, still, is shown across planetariums around the world, so that one you could see and get some insights and visualizations onto the potential for how the universe might find itself in its end game, but there's no answer. I have no answer for you on that because it's a hotly debated concept in astrophysics.

Brian Lehrer: Jim, thank you very much. I want to acknowledge that you're known as one of the most enthusiastic science communicators that we know, and you've been an advocate for using science visualization, which I guess is the kind of thing you do at the Planetarium. Of course, it's a visual experience. Science visualization and education, what do you think people take away from a show like this that they might not get from reading an article or a textbook, or how can you apply it, if at all, in the classroom?

Dr. Jackie Faherty: Well, we made a discovery during this show that is evidence as to how visualization drives scientific results as well. Astrophysics is the original visualization scientific field. You have to look. I can't hold any of my objects in my hand, can't hold a star in my hand. I have to visualize them. I always tell people that my colleagues in paleontology and ornithology, they get to go to Mongolia and Patagonia, and they get to go and find some skulls and then look around and see where they are.

I don't have a field site to go to. I can go outside at night and look up, but I want to leave the Earth and fly around. That's the Planetarium. You come in. You walk in these doors. You sit in that dome. We load up the digital universe, and we fly, and you get to explore like you're in Star Trek, and I know that sounds a little extreme, but it's not. We are exploring. We're figuring things out.

There's things you just can't figure out if all you're doing is looking at a two-dimensional plot on your screen. You need a more immersive experience for what is essentially the biggest map that we have, the entire universe. There's lots of structures. There's lots of things to discover, and as we were playing around in this show, we were playing with this simulation of the Oort cloud, and we made a discovery, Brian, so we can do it.

Brian Lehrer: So exciting, and you are definitely the first guest ever on the show to say, "We load up the visual universe, and then we fly." Dr. Jackie Faherty, astrophysicist, science educator at the American Museum of Natural History, and curator of Encounters in the Milky Way, now open at the Hayden Planetarium. This was so much fun. Thank you for sharing it with us.

Dr. Jackie Faherty: Thank you, Brian.

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