Brian Greene goes to 11 — again

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

The Universe of Leonard Susskind

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, Dr. Michelle Thaller talks with Susskind about his extraordinary life in physics. And Susskind offers a tantalizing glimpse into his recent work on the holographic principle, which suggests our universe may be a far, far stranger place than humans have yet imagined.


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: Linda Cicero / Stanford News Service

Mars Goes Organic

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 month, in the journal Science, NASA astrobiologist Dr. Jen Eigenbrode and her team published a stunning discovery. The Curiosity rover on Mars had found rocks that contain organic molecules — the building blocks of life.

On this episode of Orbital Path, Dr. Michelle Thaller sits down with Eigenbrode to understand what this discovery really says about the possibility of life on Mars.

This episode of Orbital Path was 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

Earth, Desert Planet?

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 dehydration isn’t anything we’ll have to worry about in our lifetimes. But in 200 million years — not all that long, in astronomical terms — our planet could resemble the desert world of Frank Herbert’s “Dune.”


Orbital Path is produced by David Schulman. The program is edited by Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Hosted by Dr. Michelle Thaller.

The music heard in this episode is “Austin 1” by Manwomanchild.

Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance.

Mars image credit: NASA

Our Darkening Universe

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 announced new findings about the rate at which the universe is expanding — findings which simply cannot be explained by physics as we know it.

It’s weird and profound stuff. Our story begins a century ago, with a riddle posed by a curious part of Einstein’s Theory of General Relativity — something called the “Cosmological Constant.” The fate of the universe just may hang in the balance.

This episode of Orbital Path was 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: David Schulman

Introducing…Telescope!

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 creating artificial gravity on spacecraft. And Carter Nyhan wonders whether the stars guiding mariners ancient and modern, were, by the time their light reached the earth, completely kaput. Is the twinkling night sky actually a graveyard of dead stars?

Orbital Path is produced by David Schulman. The program is edited by Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Hosted by Dr. Michelle Thaller.

Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance.

Image credit: NASA image of the International Space Station, where gravity does, in fact, still apply.

Star Death Tango

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 had predicted. It sent Gamma rays out into deep space. It created an immense cloud of gaseous gold.

And, 130 million years later, astronomers on earth witnessed the final 100 seconds of these two stars’ dance of death. It’s taught us where gold came from, and helped humans understand other intractable mysteries of the universe.

In this episode of Orbital Path, Dr. Michelle Thaller speaks with two astronomers who watched this cosmic death tango from the best seats in the house.

We’ll hear from Dr. Vicky Kalogera. She’s Director of CIERA — the Center of Interdisciplinary Exploration and Research in Astrophysics at Northwestern University. Kalogera was a lead author on a journal article on the neutron star collision co-authored by close to 4,000 scientists.

We’ll also hear from physicist Mike Landry. He’s Head of LIGO Hanford — one of the sites that, in collaboration with Italy’s VIRGO detector, measured the neutron stars’ characteristic gravitational waves.



Orbital Path is produced by David Schulman. The program is edited by Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Hosted by Dr. Michelle Thaller.

Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance. More at sloan.org

Image credit: CALTECH/NSF/LIGO Sonoma State University/A. Simonnet
Neutron star audio chirp credit: LIGO/University of Oregon/Ben Farr

Ozone Disaster Redux

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 place if not for the Montreal Protocol and the so-called “blue sky” scientific research — research for curiosity’s sake — that led to the discovery of the rapid deterioration of the ozone layer, and its causes

In this episode, we return to a program originally broadcast in January 2017 — one that is perhaps even more relevant today.

Orbital Path is from PRX and produced by David Schulman. Justin O’Neill produced this episode. Orbital Path is edited by Andrea Mustain, with production oversight by John Barth and Genevieve Sponsler. Hosted by Dr. Michelle Thaller.

Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance.

Fireside Physics: A Solstice on Saturn?

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, anyone?


Orbital Path is produced by David Schulman. The program is edited by Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Hosted by Dr. Michelle Thaller.

Photo credit: NASA

From Another Star

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 Thaller about an asteroid that watchers in Hawaii recently sighted:  a mysterious, massive, cigar-shaped object. 

Millions of years into its journey, it was traveling faster than any spacecraft ever built by humans. It’s the first object ever known to visit our solar system that originated in the orbit of another star. Too fast to be trapped by our sun’s gravity, it’s now traveling a path that will take it back into deep, interstellar space.



Orbital Path is produced by David Schulman. The program is edited by Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler. Hosted by Dr. Michelle Thaller.



Illustration credit: ESO/M. Kornmesser