Orbital Path

Astronomer Michelle Thaller takes a look at the big questions of the cosmos and what the answers can reveal about life here on Earth. From podcast powerhouse PRX, with support from the Sloan Foundation.


  • Building 29

    Dec 21 2018

    All things in the cosmos have a lifespan, from the smallest particles to the most ancient suns. Everything has its season. Every season must come to an end. And this episode marks the end of Orbital Path. So, for the last transit of our podcast, Dr. Michelle Thaller and producer David Schulman join NASA astrobiologist Dr. Jen Eigenbrode on a site visit to one of Michelle’s very favorite places at Goddard Space Flight Center. It’s building 29, where NASA builds and tests spacecraft in some of t...more

  • Hello, Asteroid!

    Nov 30 2018

    Asteroids, as the dinosaurs found out, can have big effects on life on Earth.  Sixty-five million years ago, an asteroid crashed into the Yucatán. The impact caused apocalyptic tsunamis and volcanic eruptions. Grit and ash blotted out the sun. It wiped out species that had roamed the Earth for millions of years. Yet asteroid hits also were critical to the origins of life on Earth. Asteroids may well have been the bringers of water, of carbon, even of amino acids — the building blocks of life. ...more

  • Black Holes from the Dawn of Light

    Oct 26 2018

    To make a black hole, you need to think big. Really big. Start with a star much bigger than the sun — the bigger the better. Then settle in, and wait a few million years for your star to die. That should do the trick, if you want to get yourself a garden-variety black hole. But there’s another kind of black hole. They are mind-boggling in size. And deeply mysterious: Super-massive black holes. Last year, in the journal Nature, a team of astronomers reported finding one with the mass of 800 m...more

  • Space Lasers for the Home Planet

    Sep 28 2018

    On September 15, 2018, the last Delta II rocket lifted off from Vandenberg Air Force base, in California. It carried into orbit IceSat-2 — a satellite equipped with perhaps the most sophisticated space laser ever built.   NASA didn’t put it up there to shoot down rogue asteroids. Instead, it’s taking aim — with exquisite precision — at Earth.   On this episode of Orbital Path, Dr. Michelle Thaller talks with Tom Wagner. He’s been looking forward to the launch of IceSat-2 for a decade. Officially...more

  • Brian Greene goes to 11 — again

    Aug 31 2018

    We live our lives in three dimensions. But we also walk those three dimensions along a fourth dimension: time. 

Our world makes sense thanks to mathematics. Math lets us count our livestock, it lets us navigate our journeys. Mathematics has also proved an uncanny, stunningly accurate guide to what Brian Greene calls “the dark corners of reality.”

 But what happens when math takes us far, far beyond what we — as humans — are equipped to perceive with our senses? What does it mean when mathema...more

  • The Universe of Leonard Susskind

    Jul 27 2018

    To hear Leonard Susskind tell it, we are living in a golden age of quantum physics. And he should know. Susskind is a grandee of theoretical physics. In the 1960s, he was one of the discoverers of String Theory. His friends and collaborators over the years include the likes of Nobel Prize winners Gerard ‘t Hooft and Richard Feynman. And, for more than a decade, Susskind engaged in an intellectual clash of the Titans with Stephen Hawking — and came out on top. On this episode of Orbital Path,...more

  • Mars Goes Organic

    Jun 29 2018

    For a long time, probably as long as we have been gazing up at the night sky, people have been asking ourselves: Are we alone? Is there life out there, anywhere else in the universe? For modern Earthlings, our fascination with extraterrestrial life has focussed on one place in particular: Mars. The planet today is a forbidding, arid place. But billions of years ago, Mars may have had a gigantic ocean. It was, like Earth, just the kind of place you’d think life could get started. Earlier this...more

  • Earth, Desert Planet?

    Mar 23 2018

    Zoe is in 8th grade. She’s a student in Mr. Andersen’s Earth science class at a public school in Brooklyn. Lately, she’s been concerned about the future of the planet. Specifically, Zoe has been learning about the phenomenon of planetary dehydration — and she wanted to ask Dr. Michelle Thaller what would happen if Earth lost its water. It’s part of a new Orbital Path project called “Telescope,” where Dr. Michelle Thaller fields astronomy questions from public school students. Michelle says d...more

  • Our Darkening Universe

    Mar 09 2018

    Secrets of the universe? A glimpse of the whiteboard in the office of Nobel Prize-winning astrophysicist Adam Riess. Adam Riess was only 41 when he was named a Nobel Prize winner. The Johns Hopkins distinguished professor of astronomy shared in the award for his work on something called “dark energy” — a discovery that over the past 20 years has profoundly shifted our understanding of the universe. Riess made news again recently when he and colleagues working with the Hubble Space Telescope ...more

  • Introducing…Telescope!

    Feb 23 2018

    Instead of grappling with the big, cosmic questions that preoccupy adults, this week on Orbital Path we’re doing something different. We’re grappling with the big, cosmic questions that preoccupy kids. It’s part of a new project called “Telescope,” where Dr. Michelle Thaller takes on the really big questions in astronomy—from public school students. In this episode, Michelle fields questions from Mr. Andersen’s Earth Science class at MS 442, a public school in Brooklyn. Sarah Cole asks about...more

  • Star Death Tango

    Feb 09 2018

    On August 17, 2017, an alert went out. Gravitational wave detectors in Louisiana and Washington state had detected a disturbance from deep space. The effect was subtle — these detectors and a sister site in Italy measure disturbances smaller than a proton. But the evidence was dramatic. And the story they told was truly cataclysmic: A pair of neutron stars had spiraled to their deaths. That apocalyptic collision of two super-dense stars bent the very fabric of space time — just as Einstein h...more

  • Ozone Disaster Redux

    Jan 26 2018

    Scientists in 1985 discovered something that threatened the world we live in: The ozone layer had a hole in it. A big one. And this hole was growing very quickly. If it continued to grow, the consequences would be dire. Presented with the science, world leaders came up with an international agreement. The Montreal Protocol, as the treaty was called, may elicit shrugs today. But it staved off disaster for Earth. It was a remarkable success story, and our planet today would be a very different ...more

  • Fireside Physics: A Solstice on Saturn?

    Dec 29 2017

    In this darkest season of the year, Dr. Michelle Thaller and NASA astronomer Andrew Booth curl up by the fire. Gazing into the embers, red wine in hand, they consider the meaning of the winter solstice — on other planets. Like Uranus, where parts of the planet go 42 earth years without seeing the sun. Or Mars, where winters are made colder by an orbit politely described as “eccentric.” Or Saturn — where winter’s chill is deepened by the shadow of the planet’s luminous rings.  Marshmallow, anyo...more

  • From Another Star

    Dec 15 2017

    NASA’S office of planetary defense isn’t worried about Klingons or Amoeboid Zingatularians.  They worry about asteroids and comets.  Like the one that exploded over Chelyabinsk, Russia in 2013. It was about 20 yards across. An asteroid 150 yards in diameter could take out a city. An even bigger one — as the dinosaurs reading this will attest — could change earth’s ecology, and lead to mass extinctions. Kelly Fast, program manager for NASA’s office of planetary defense, tells Dr. Michelle Thal...more

  • Winter’s Night Sky

    Dec 01 2017

    These days, astrophysicists like Dr. Michelle Thaller use instruments to probe the distant reaches of our galaxy, and far beyond. They use interferometry, the Hubble space telescope, and other technology impossible to imagine when the constellations of the winter sky were named. But, as the season changes and Orion returns to view, Michelle still finds plenty of wonder left for us to see — even with the naked eye — in the cold, clear air of a winter’s night.

 Orbital Path is produced by David...more

  • Aliens Again!

    Nov 17 2017

    We’ve got some awkward news to share, folks: The producer of Orbital Path is claiming he’s been abducted by space aliens. So this week, we’re dusting off the theremin and returning to one of our favorite early episodes — “Must Be Aliens.” Dr. Michelle Thaller talks with Phil Plait — AKA the “Bad Astronomer” — about the Kepler mission to find planets circling other stars … and why we humans are so quick to ascribe the unknowns of the cosmos to aliens. In the two years since this episode was or...more

  • Time and Space in the Kingdom of Bhutan

    Nov 03 2017

    The Himalayan kingdom of Bhutan avidly guards its traditional culture. Bhutan is a nation that — instead of looking to GDP or debt ratios — measures success by an index of “Gross National Happiness.” In this episode of Orbital Path, Dr. Michelle Thaller describes her recent adventures in Bhutan — including a climb to a Buddhist monastery perched on the face of a cliff. In that rarefied air, Michelle was confronted by a link between the thinking of contemporary astrophysicists and old-school Bhu...more

  • The 11 Dimensions of Brian Greene

    Oct 20 2017

    We live our lives in three dimensions. But we also walk those three dimensions along a fourth dimension: time.

 Our world makes sense thanks to mathematics. Math lets us count our livestock, it lets us navigate our journeys. Mathematics has also proved an uncanny, stunningly accurate guide to what Brian Greene calls “the dark corners of reality.” 

But what happens when math takes us far, far beyond what we — as humans — are equipped to perceive with our senses?  What does it mean when mathem...more

  • Minisode 5: Scary Math

    Sep 29 2017

    In a scary time, in a scary world, in a scary universe, NASA astronomer Andrew Booth says one of the things that frightens him most is math. Specifically, the power of mathematics to describe the universe. That’s because, beyond the comforting world of Newtonian physics, math gets mind-bendingly weird. So from the relative safety of their backyard hot tub, Dr. Michelle Thaller and Booth (who happen to be married) try to sort out what it really means to live not in just three dimensions, but in...more

  • Episode 22: Journey to the Sun

    Sep 15 2017

    Locked up on the Greek island of Crete, Icarus and his dad made wings out of  beeswax and bird feathers. They soared to freedom — but Icarus got cocky, flew too close to the sun, and fell into the sea.  A few thousand years later, NASA is ready to do the job right. The Parker Solar Probe is scheduled to fly in 2018. The spacecraft has a giant heat shield, tested to withstand 2,500-degree temperatures. For something so basic to all of our lives — and fundamental to the science of astronomy — t...more

  • Minisode 4: Hot Tub Physics!

    Sep 01 2017

    After a full day in a clean suit, there’s nothing like … a dip in the hot tub. NASA astronomer Andrew Booth spends his days working with lasers, developing some of the word’s most advanced telescopes. When he gets home from work, he loves to pour a glass of wine and slip into the hot tub. And ponder some of the weirder aspects of astrophysics. Orbital Path host Dr. Michelle Thaller (who happens to be married to Booth) rather avidly shares this enthusiasm. For Orbital Path’s first adventure i...more

  • Episode 21: First Light

    Aug 18 2017

    There was a time before planets and suns. A time before oxygen. You could say there was time, even, before what we think of as light. Back in 1989, the Big Bang theory was still in question. But that year, a NASA team led by cosmologist John Mather launched a mission to probe the earliest moments of the universe. Mather won the Nobel Prize in Physics for his work on the Cosmic Background Explorer (COBE). This work dramatically confirmed the Big Bang theory — and, as part of it, Mather and hi...more

  • Episode 20: Holy Sheet!

    Aug 04 2017

    NASA is relying on hi-tech lasers — and some vintage U.S. Navy hand-me-downs — to learn about the polar regions of a remarkable, watery planet. It’s located in the Orion spur of our galaxy. NASA scientists have detected mountain ranges completely under ice. But the remaining mysteries of the ice here are profound, and what the science tells us could have dramatic impact on human life. In this episode, Dr. Thaller visits with two key members of NASA’s IceBridge mission — Christy Hansen, Airbor...more

  • Mini-sode 3: Dr. Thaller Helps You Prep for The Eclipse

    Jul 21 2017

    The big one is coming! That is, the total solar eclipse of Aug. 21. Dr. Thaller shares her wisdom on how best to view the eclipse and its larger implications for science. Orbital Path is produced by David Schulman and edited by Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Hosted by Michelle Thaller.

  • Mini-sode 2: What up, Jupiter?

    Jun 30 2017

    Recently, we’ve started to get the first images back from Juno, which is on a mission to Jupiter. Host Dr. Michelle Thaller walks us through the results so far and how you can participate in what Juno discovers next. [Image of Jupiter from the Juno spacecraft.](https://www.nasa.gov/missionpages/juno/images/index.html)_

  • Episode 19: We Are Stardust

    Jun 21 2017

    Dr. Michelle Thaller visits the NASA lab that discovered that meteorites contain some of the very same chemical elements that we contain. Then, Michelle talks to a Vatican planetary scientist about how science and religion can meet on the topic of life beyond Earth.

  • Episode 18: Cassini Countdown

    May 23 2017

    When the Cassini spacecraft blasted into space on October 15, 1997, even the most optimistic scientists would have had a hard time predicting the mission’s success. One of Cassini’s biggest legacies will be how she gave us a clearer picture of Saturn’s 62 moons, including two worlds that scientists now think could potentially host life. Dr. Michelle Thaller speaks with the Cassini mission’s Project Scientist Linda Spilker and with Julie Webster, a longtime Cassini engineer. Cassini will crash...more

  • Making (Gravitational) Waves

    Apr 21 2017

    Nearly 100 years after Einstein predicted the existence of gravitational waves — huge undulations in the fabric of space-time itself — in 2015, detectors here on Earth finally picked up the signal of these massive disturbances. Dr. Michelle Thaller pulls apart the power and mystery of gravitational waves, and talks with Dr. Janna Levin, theoretical astrophysicist and author of the book, Black Hole Blues and Other Songs From Outer Space. Image caption: The LISA Pathfinder Mission paves the wa...more

  • Mini-sode 1: NASA’s NICER Mission

    Apr 03 2017

    Listeners, we’ve heard you! You requested more episodes, so we present the first of our mini episodes. They’ll arrive two weeks after each monthly regular episode, and include Michelle Thaller’s insight on the latest space news. Enjoy episode one: NASA’s NICER (Neutron star Interior Composition Explorer) mission will launch in May. Michelle explains the NICER mission’s many applications, including the possibility of using neutron stars as intergalactic global positioning systems. Orbital Pat...more

  • Lessons in Landslides

    Mar 20 2017

    Space science can help track what’s happening on Earth. In this podcast episode, Orbital Path talks landslides and the satellites that monitor them for the third anniversary of the deadliest landslide in US history. On March 22, 2014 a 650-foot hillside collapsed and covered the community of Oso, Washington. Forty-three people died. Hear from scientists working to investigate this landslide and predict future ones, as well as a woman who witnessed the landslide. David Montgomery studied the ...more

  • Space Robots to Europa!

    Feb 24 2017

    Galileo discovered Europa, Jupiter’s fourth-largest moon, in 1610. In 1977, the Voyager spacecraft buzzed past and we realized it was covered in ice. It took a few more years to understand that it also likely had unfrozen liquid water oceans. In this episode, Kevin Hand, Deputy Project Scientist for the Europa mission at NASA’s Jet Propulsion Lab (JPL) explains how his team plans to launch a series of missions to orbit, land on, and hopefully explore the curious moon’s deep salty oceans with ...more

  • How the World Came Together to Avoid Ozone Disaster

    Jan 23 2017

    In 1985, the British Antarctic Survey discovered something that shocked scientists around the world: the ozone layer had a hole in it. And the hole was growing very quickly. When they were presented with the problem, politicians and world leaders quickly came up with an international agreement to immediately reduce chlorofluorocarbons released into the atmosphere. It was a success story, and we can learn from it on climate change. In the episode: Atmospheric chemist Dr. Susan Solomon shares h...more

  • Warning: Space May Wreak Havoc on Your Body

    Dec 16 2016

    (17 May 2009) — Astronaut Mike Massimino peers through a window on the aft flight deck of the Earth-orbiting Space Shuttle Atlantis during the mission’s fourth session of extravehicular activity (EVA) to refurbish and upgrade the Hubble Space Telescope. Going to Mars is hot right now, just ask Matt Damon. But would you go if you knew your bones would turn into something called “pee brittle”? Former astronaut Michael Massimino reveals the uncomfortable side of liftoff. And Dr. Jennifer Fogarty ...more

  • In Search of Planet 9

    Nov 19 2016

    Proposed mockup of our solar system (the sun is the tiny yellow dot in the middle), and the proposed orbit of Planet 9 (called Planet X here). (Courtesy of Scott Sheppard / Carnegie Institution of Washington) An Orbital Path episode all about…an orbital path! Planet 9’s, to be exact. The replacement for Pluto as our solar system’s ninth planet is out there somewhere, and astronomers can see the ripples it creates, especially at this time of year. In this Episode: On November 5, 2012, astronom...more

  • Black Hole Breakthroughs

    Oct 22 2016

    Scientific discovery can happen in two ways: “Eureka!” moments of sudden understanding, where researchers glean unexpected insight into new phenomena. Or, a slower, less glamorous hunt for truth that happens day-after-day, for years. But both methods can lead to new understandings that pushes the field forward for future breakthroughs. In this episode: the sudden realization that led to the discovery of the first ever black hole, and another more methodical search for the moment that a star d...more

  • Done in the Sun

    Sep 30 2016

    Coronal mass ejection courtesy of NASA Solar Dynamics Observatory The sun can seem like a friendly celestial body. It is the source of summer, crops, and basically all life on Earth. But just as the sun decided when life on Earth could begin, it will also decide when life on Earth will definitely end. Dr. Michelle Thaller speaks with Dr. C. Alex Young, Associate Director for Science in the Heliophysics Division at NASA’s Goddard Space Flight Center. We’ll hear about the impressive fleet of sp...more

  • Howdy, Neighbor

    Sep 02 2016

    When Proxima b’s discovery appeared in Nature on August 24, the media breathlessly announced a new Earth-like planet just 4.2 light years away from Earth. Astronomers have, for years, anticipated a planet orbiting Proxima Centauri. Michelle Thaller talks with astrophysicist Dr. Patricia Boyd about NASA’s ongoing search for exoplanets and what’s the next step in human exploration of other worlds. Don’t miss the episode extra below. Michelle stands outside the clean room where the James Webb Spa...more

  • A Tale of Two Asteroids

    Aug 22 2016

    The asteroid belt is portrayed in movies as a crowded place with massive rocks bouncing each other like pool balls, capable of sending a mile-wide missile hurtling toward Earth at any moment. The reality is much more fascinating. Host Dr. Michelle Thaller speaks with Dr. Lucy McFadden, Co-Investigator of NASA’s Dawn Mission to orbit the asteroids Vesta and Ceres. She shares what they’ve learned by traveling 130 million miles to visit places we’ve always viewed from afar. Episode Extras This i...more

  • Chasing An Eclipse

    Jul 15 2016

    Michael Kentrianakis loves eclipses and has seen them from all over the world. Host Michelle Thaller and Mike talk about the stages of the eclipse we can see in his video that went viral a few months ago after an Alaska Airlines flight. That flight was diverted for better eclipse viewing thanks to Joe Rao, who has convinced airlines to do this before. We’ll hear how he pulled it off and learn where best to view the August 21, 2017 total solar eclipse. Episode Extras Mike Kentrianakis taking...more

  • A World Without Boundaries

    Jun 15 2016

    From space, the view of earth has no boundaries for countries, no barriers to achievement. Michelle Thaller speaks with Aprille Ericcson, a senior engineer at NASA, about her career path and about current challenges recruiting more women and minorities into engineering and space science. Orbital Path is hosted by astronomer Michelle Thaller and produced by Lauren Ober. Learn more about them here.

  • Michelle & Her Mom

    Apr 29 2016

    Michelle (L), her mom and sister. In this special Mother’s Day episode, Michelle talks with her mom about what it was like raising a space-obsessed daughter in Wisconsin and watching her grow into a scientist. Big hair ’80s. Michelle’s sister, Michelle and her mom. Michelle’s sister, Michelle, and her mom today.

  • In Praise of Volcanoes

    Apr 07 2016

    Astronomer Michelle Thaller talks with Ashley Davies, a research scientist at the Jet Propulsion Laboratory, about the importance of volcanoes in the creation of Earth and how the study of volcanos in space can help us understand life here. Davies has journeyed to remote volcanos like Mt. Erebus in Antarctica and Erta Ale in Ethiopia as a way to help map volcanos like those on Jupiter’s moons, Io and Europa, and in turn come that much closer to understanding how life began. — Lauren Ober, Produ...more

  • The Most Dramatic Sky

    Feb 18 2016

    The most rare objects in the night sky are only visible in some extreme places. Dr. Michelle Thaller introduces us to Dr. Anna Moore, a scientist whose trips to Antarctica help us better understand the solar system.

  • Mass Extinctions Get Personal

    Jan 15 2016

    Host Dr. Michelle Thaller talks to Prof. Lisa Randall, a theoretical particle physicist at Harvard, about her new book, Dark Matter and the Dinosaurs: The Astounding Interconnectedness of the Universe. The scientists explore what caused the dinosaurs’ extinction and the role dark matter plays in the universe and our world.

  • Must Be Aliens

    Dec 11 2015

    Host Michelle Thaller talks with astronomer and author Phil Plait of Slate’s Bad Astronomy blog about this conundrum: why are humans so quick to explain the unknowns of the cosmos as aliens? And why is this healthy imagination important in science? — This is our first episode of Orbital Path, a new monthly series from PRX. Learn more here and check out our other science series, Transistor.