Show for April 15, 2012: Astrophysicist Michael Turner
Michael Turner, of the University of Chicago and Kavli Institute, has had his hands in some of the biggest cosmological advances of recent years. He’s also contributed to the scientific lexicon, coining the term “dark matter” and presaging its discovery. We talked about that and some of the universe’s other big conundrums.
Click the Play arrow above to listen to the show, or you can download the MP3 here (if using a Mac, control-click the link and choose “Save Link As…” If using a PC, right-click and choose Save Target As…”)
Show for Jan. 15, 2012. The Theory that Changed the Universe: Anthony Aguirre on General Relativity. Pt 2 of 2.
Cosmologist Anthony Aguirre and I continue our jaunt through General Relativity. Last week we presented some of the basics. This week, we talk about the evidence, the impacts and implications, including the cosmological constant, the expanding universe, gravity waves, time dilation, black holes, and spacetime singularities.
- What would it mean for relativity if those recently-reported faster-than-light neutrino observations were confirmed?
- If mass changes spacetime, and the Higgs field gives rise to mass, what is the relation between the Higgs and spacetime?
- A gedankenexperiment: What would happen if you fell through the earth?
- In black holes, space takes on a time-like directionality. Huh?
Show for Jan. 8, 2012. The Theory that Changed the Universe: Anthony Aguirre on General Relativity. Pt 1 of 2.
It was Einstein’s greatest idea, and one of the boldest leaps of scientific imagination ever. Much of what physicists know (or think they know) about space, time and the cosmos depends on it. But General Relativity is usually brushed over in pop sci accounts, because GR is considered too GD difficult for ordinary brains. Even on this scientifically-minded program, we’ve given it pretty cursory treatment. But not this time. I’m devoting two whole shows to the subject with physicist Anthony Aguirre. He’s taught relativity and applies it in his own cosmological research, and does a yeomanly job here of making some very alien concepts approachable.
Included in Pt 1: From Special to General Relativity, gravity reconsidered, the geometry of spacetime, practical implications of GR, and evidence for the theory.
I’m not sure what those equations are behind Anthony Aguirre, but here’s one version of Einstein’s field equation, which we discussed in the program:
Click the Play arrow above to listen to the show, or you can download the MP3 here (if using a Mac, control-click the link and choose “Save Link As…” If using a PC, right-click and choose Save Target As…”)
Show for Nov. 27, 2011. Brian Greene on Black Holes.
First broadcast in Jan. 2009: physicist and master explainer Brian Greene on the space-, time-, and mind-bending properties of black holes. This originally aired as part 1 of a black hole double-header. You can hear the second installment, with the physicist Leonard Susskind, here.
You can download the MP3 here (if using a Mac, control-click the link and choose “Save Link As…” If using a PC, right-click and choose Save Target As…”)
Show for June 26, 2011. Jennifer Ouellette and The Calculus Diaries.
How one mathophobe conquered her fears, and others can, too. For years, science journalist Jennifer Ouellette made a living writing about subjects like physics, while avoiding the mathematics. Finally, she resolved to shed the dread and confront calculus, as she relates in her recent book The Calculus Diaries: How Math Can Help You Lose Weight, Win in Vegas, and Survive a Zombie Apocalypse. We talked about her reconciliation with math, the history and uses of calculus (e.g., predicting rates of zombification), the sources of math anxiety and techniques for getting over it.
We also played an excerpt from this song, by Matthew Kaney:
Click the “play” arrow above to listen to the show, or download the MP3 here (if using a Mac, control-click the link and choose “Save Link As…” If using a PC, right-click and choose Save Target As…”)
Incidentally, Jennifer’s hubby is the physicist Sean Carroll, who we interviewed here on the subject of time.
Show for April 17, 2011. The Dark Universe.
Ordinary matter is so 20th century. In recent decades, scientists have found that the vast bulk of the universe (95-96 percent) consists of some as-yet-unidentified thingums known as “dark matter” and “dark energy.” Astrophysicist Rocky Kolb (pronouned “Kobb,” BTW) explains what we know and don’t know about these mystery ingredients. Then science writer Richard Panek describes the sometimes bumpy road to their discovery.
Click the “play” arrow above to listen to the interview, or download the MP3 here.
Show for Feb 27, 2011. Not Totally Insane: Physicist Anthony Aguirre on the New Cosmology
I thought I knew a thing or two about the universe: nearly 14 billion years old, started with the big bang, expanding at a certain rate, etc., etc. Turns out the story may be much more complicated, if the latest theories are right. What I thought I knew applies only to the observable universe, but outside that little patch of ours, things may be very different. Possibilities include varying rates of inflation, different physical laws, maybe entirely separate universes. Cosmologist Anthony Aguirre of UC Santa Cruz joins us to speculate on what’s out there beyond the horizon.
Not so simple: The universe may be a lot more complicated than this standard view suggests.
Click the “play” arrow above to listen to the interview, or download the MP3 here.
Show for Dec. 12, 2010: Sean Carroll—the Quest for the Ultimate Theory of Time
Cal Tech theoretical physicist and Cosmic Variance blogger Sean Carroll considers various ideas of time, including Newton’s, Einstein’s and Sean’s own pet theory (think bubbles and baby universes). We also talk a lot about entropy—the basis of time’s arrow, Sean explains—and perforce about eggs.
You can download the MP3 here.
Show for Sunday, Nov 14: Particle Physics Primer, Pt. 2
Our adventures in subatomic wonderland with particle physicist Bruce Schumm continue. We’ll pick up where we left off last week, searching for underlying order—maybe even simplicity—amidst all the quantum complexity. We’ll learn about the Feynman rules, symmetry and gauge theory. We’ll hear about the gaps in the Standard Model of particle physics, the search for missing pieces (like the Higgs field) and the possibility of grand unification (a “theory of everything”).
Click the “play” arrow above to listen to the show, or download the MP3 here.
While sailing into some deep waters, we’ll be sure to pass out life jackets. Even physicists need flotation devices, like Feynman diagrams (discussed on today’s show):
This is a simple electromagnetic interaction: two electrons meet, exchange a photon and go their separate ways. Below are some more diagrams, including examples of two other forces—the weak nuclear force and strong nuclear force:
Want to draw your own Feynman diagrams? Here are the rules.
Show for Nov 7, 2010. The Universe Writ Small: A Primer on Particle Physics, Pt. 1
We get a tour of the subatomic realm and an introduction to particle physics from Bruce Schumm. He’s a professor of physics at UC Santa Cruz, a particle man himself and the author of Deep Down Things: The 
Breathtaking Beauty of Particle Physics. And while media coverage tends to favor the speculative fringes of physics theory (extra dimensions, man-made black holes, disembodied brains in space), we’re going back to basics. We’ll focus on the Standard Model of particle physics, which encompasses most of what scientists know about the universe at small scales. And don’t let its drab-sounding name fool you. The Standard Model is a catalog of marvels that strain the limits of human understanding (mine, at least).
In this first of a two-part series, we’ll learn about some of the basic ingredients of the model, including particles, fields and forces. Coming up in part two, the deeper organizing principles (gauge theory and symmetry), holes in the Standard Model and next steps.
Click the “play” arrow above to listen, or download the MP3 here.
Show for Apr 18, 2010. Leonard Susskind: The Black
Hole War
This is a rebroadcast (with a new postscript) of an interview originally aired in 2009. Leonard Susskind—theoretical physicist, one of the fathers of string theory—describes some of the extraordinary, mind-blowing implications of black holes. E.g., the holographic theory of the universe. Some of these implications touched off a long-running debate between Susskind and Stephen Hawking. Susskind gives us blow-by-blow account.
Show for March 21, 2010. Physics at the Edge: Anil Ananthaswamy
In recent years, physics theory has gotten way ahead of the evidence. Now, researchers are going to extremes to figure out what’s true and what isn’t. They’ve launched a set of hugely ambitious experiments in some of the most forbidding places on Earth, from the South Pole to Himalayan mountaintops. Physics writer Anil Ananthaswamy travelled to these remote laboratories, and he tells us what he saw.
Learn more about Anil’s book and see photos from his travels here.
Show for Nov 29, 2009. Frank Wilczek: The Bottom of Things
Nobel Prize-winning physicist Frank Wilczek on the fundamental ingredients of physical reality. Where mass comes from, why empty space isn’t, and other marvels of modern physics explained. Wilczek’s latest book is The
Lightness of Being: Mass, Ether and the Unification of Forces. (Originally broadcast Nov, 2008)
