5.5.14: The Sixth Extinction & Why Is The Sky Blue?

May 5, 2014

Credit Marco Bellucci via flickr Creative Commons

On today's Word of Mouth, we tackle that most pervasive of human curiosities: Why is the sky blue? You might have some vague understanding that you could give to an inquiring child, or, if you're like author Phil Plait,  “You look him or her right in the eye and say, ‘It’s because of quantum effects involving Rayleigh scattering combined with a lack of violet photon receptors in our retinae.’" That explanation might be a bit too advanced for young minds, so Phil wrote the book on how actually to explain such scientific quandaries to kids.

Listen to the full show and click Read more for individual segments

Sixth Extinction

  • While we may be most familiar with the asteroid that wiped out the dinosaurs, there have been exactly five mass extinctions in the history of life on earth. Catastrophic periods where biological diversity, and the sheer number of living organisms on the planet, were reduced by staggering proportions. In a new book called The Sixth Extinction: An Unnatural History, Elizabeth Kolbert of the New Yorker asks whether we are right now living in the midst of another mass extinction – one caused not by an asteroid, or an ice age – but by us.  The human race.

TLDR: The Million Dollar Homepage

  • While most students take out loans or take on part-time work to fund their education, Alex Tew chipped away at the cost a different way… one pixel at a time.

Why is the Sky Blue?

  • Phil Plait is now the man behind the Bad Astronomy blog at Slate, and he joins us now to correct the record and offer a simpler explanation about why the sky is blue.


  • April was National Poetry Month, and all month long we asked you to send us your public radio inspired haikus. We were so impressed with your submissions and felt some were just begging to be recited. Without further ado, your public radio haikus.

Coaching in the Classroom

  • Craig Owens is an associate professor of English at Drake University, and co-creator of a program that brings academics into the locker-room. He spoke with us about his new program, “Coaching in the Classroom.”

Science of Superheros

  • Professor Michael Dennin from the University of California in Irvine, discusses his course "The Science of Superheros", which recently changed its title to "Science Fact, Science Fiction" to avoid disappointing superhero fans.