Orbital Path

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. That’s a big reason why NASA is on a mission to Bennu. This asteroid is like an ancient fossil of our solar system — largely unchanged since the time the planets formed. In December, after a billion-mile journey, NASA’s Osiris-Rex mission arrives at Bennu. And, for the first time, a spacecraft will try to actually bring back an asteroid sample to Earth. On this episode of Orbital Path, Dr. Michelle Thaller sits down with Dr. Amy Simon — a senior scientist at NASA’s Goddard Space Flight Center, and a key player on the Osiris-Rex mission. Michelle and Amy talk about the mission, Amy’s work to probe the origins of the solar system, and one other thing:  The remote chance that Bennu, someday, could collide with Earth. Orbital Path is produced by David Schulman.  Our editor is Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance. Image credit: NASA/Goddard/University of Arizona.

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 million suns. It’s the most distant black hole in the known universe. And it’s so ancient, it dates to a time when it seems light itself was only just beginning to move. On this episode of Orbital Path, Dr. Michelle Thaller talks with astrophysicist Chiara Mingarelli — Flatiron Research Fellow at the Center for Computational Astrophysics in New York. Using a special gravitational wave observatory, Dr. Mingarelli is part of a cadre of astronomers hoping ancient super-massive black holes will soon reveal mysteries dating to the dawn of our universe. Orbital Path is produced by David Schulman. Our editor is Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance. Image credit: NASA artist’s rendering of a super-massive black hole.

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, Wagner is NASA’s Program Scientist for the Cryosphere. That means he studies the frozen regions of the Earth: Antarctica. The Arctic Ocean. The glaciers of Greenland. All places critical to understanding our planet’s changing climate.   From 300 miles above, the six laser beams of IceSat-2 won’t harm even the most light-sensitive earthling, Wagner says. But, as he describes it, the satellite will allow scientists to precisely map the retreat of ice at the poles. And that promises to teach us a great deal about how Earth’s climate will change in the years to come. Orbital Path is produced by David Schulman. Our editor is Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance. Image credit: NASA

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 mathematics tells us, in no uncertain terms, that the world exists not in three, not in four — but in no fewer than 11 dimensions?

 In this encore episode of Orbital Path (previously heard in October 2017), Brian Greene, a celebrated explainer of how our universe operates and the director of the Center for Theoretical Physics at Columbia University, sits down to talk with Dr. Michelle Thaller.  Together they dig into the question of how we — as three-dimensional creatures — can come to terms with all those extra dimensions all around us.  
Orbital Path is produced by David Schulman. Our editor is Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance. Image by: World Science Festival / Greg Kessler