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  • Shows Index
    • Amateur Astronomy (5)
      • Observing (5)
    • Astronomy (90)
      • Cosmology (16)
      • Galaxies (6)
      • Nebulae (1)
      • Observing (7)
      • Planets (24)
        • Extrasolar Planets (5)
        • Our Solar System (18)
      • Stars (11)
        • Compact Objects (3)
        • Stellar Evolution (7)
    • Listeners (11)
      • Questions Shows (9)
      • Student Questions (2)
    • People (6)
      • Doing Astronomy (2)
      • Interviews (3)
      • Meetings (4)
    • Physics (22)
      • Forces (6)
      • Particles (7)
      • Relativity (3)
    • Space Flight (1)
    • The Show (3)
      • Meetups (1)



  • Collaborators
    Universe Today Star Stryder Bad Astronomy



    Past Shows
    • Ep. 87: The End of the Universe Part 2: The End of Everything
    • Ep. 86: The End of the Universe Part 1: The End of the Solar System
    • Ep. 85: Detectors
    • Ep. 84: Getting Around the Solar System
    • Ep. 83: Wave Particle Duality
    • Ep. 82: Space Junk
    • Ep. 81: Questions on the Shape, Size and Centre of the Universe
    • Ep. 80: Craters
    • Ep. 79: How Big is the Universe?
    • Ep. 78: What is the Shape of the Universe?
    • Ep. 77: Where is the Centre of the Universe?
    • Ep. 76: Lagrange Points
    • Student Questions: Curtis High School
    • Ep. 75: Stellar Populations
    • Ep. 74: Antimatter
    • Ep. 73: Questions Show #8
    • Ep. 72: Cosmic Rays
    • Ep. 71: Gravitational Waves
    • Ep. 70: How To Win a Nobel Prize
    • Astronomy Cast Meetup at AAS Austin
    • Student Questions: Farmersburg
    • Ep. 69: The Large Hadron Collider and the Search for the Higgs-Boson
    • Ep. 68: Globular Clusters
    • Ep. 67: Building a Career in Astronomy
    • Ep. 66: How Amateurs Can Contribute to Astronomy
    • Ep. 65: The End of Our Tour Through the Solar System
    • Ep. 64: Pluto and the Icy Outer Solar System
    • Ep. 63: Neptune
    • Ep. 62: Uranus
    • Ep. 61: Saturn's Moons
    • Ep. 60: Questions Show #7
    • Ep. 59: Saturn
    • Ep. 58: Inflation
    • Ep. 57: Jupiter's Moons
    • Ep. 56: Jupiter
    • Ep. 55: The Asteroid Belt
    • Ep. 54: Questions Show #6
    • Ep. 53: Astronomy in Science Fiction
    • Special Episode: Panspermia
    • Ep. 52: Mars
    • Ep. 51: Earth
    • Ep. 50: Venus
    • Ep. 49: Mercury
    • Ep. 48: Tidal Forces Across the Universe
    • Ep. 47: Tidal Forces
    • Ep. 46: Stellar Nurseries
    • Ep. 45: The Important Numbers in the Universe
    • Listener Survey
    • Ep. 44: Einstein's Theory of General Relativity
    • Ep. 43: Questions Show #5
    • Ep. 42: Magnetism Everywhere
    • Ep. 41: The Rise of the Supertelescopes
    • Ep. 40: American Astronomical Society Meeting, May 2007
    • Ep. 39: Astrology and UFOs
    • Ep. 38: Neutron Stars and their Exotic Cousins
    • Ep. 37: Gravitational Lensing
    • Ep. 36: Gamma-Ray Bursts
    • Ep. 35: Questions Show #4
    • Ep. 34: Discovering Another Earth
    • Ep. 33: Choosing and Using a Telescope
    • Ep. 32: The Search for Neutrinos
    • Ep. 31: String Theory, Time Travel, White Holes, Warp Speed, Multiple Dimensions, and Before the Big Bang
    • Ep. 30: The Sun, Spots and All
    • Ep. 29: Asteroids Make Bad Neighbors
    • Ep. 28: What is the universe expanding into?
    • Ep. 27: Questions Show #3
    • Ep. 26: The Largest Structures in the Universe
    • Ep. 25: The Story of Galaxy Evolution
    • Ep. 24: The Fermi Paradox: Where Are All the Aliens?
    • Ep. 23: Counting Aliens With the Drake Equation
    • Ep. 22: Variable Stars
    • Ep. 21: Questions Show #2
    • Ep. 20: What We Learned from the American Astronomical Society
    • Ep. 19: Comets, Our Icy Friends from the Outer Solar System
    • Special Alert: Go See Comet McNaught
    • Ep. 18: Black Holes Big and Small
    • Ep. 17: Where does the Moon Come From?
    • Ep. 16: Across the Electromagnetic Spectrum
    • Ep. 15: Questions Show #1
    • Ep. 14: We're all Made of Supernovae
    • Ep. 13: Where Do Stars Go When They Die?
    • Ep. 12: Where Do Baby Stars Come From?
    • Ep. 11: A Universe of Dark Energy
    • iPod Issues Fix
    • Ep. 10: Measuring Distance in the Universe
    • Ep. 9: Einstein's Theory of Special Relativity
    • Ep. 8: Meteor Showers. Yes, the sky is falling.
    • Ep. 7: Getting Started in Amateur Astronomy
    • Ep. 6: More Evidence for the Big Bang
    • Ep. 5: The Big Bang and Cosmic Microwave Background
    • Ep. 4: The Search for Dark Matter
    • Ep. 3: Hot Jupiters and Pulsar Planets
    • Ep. 2: In Search of Other Worlds
    • Ep. 1: Pluto's Planetary Identity Crisis
    • Welcome to Astronomy Cast!


Ep. 83: Wave Particle Duality

  • April 7th, 2008
  • Show Notes
  • Comments(22)
  • Like it? Digg-it | Reddit | del.icio.us
Array

Have you ever heard that photons behave like both a particle and a wave and wondered what that meant? It's true. Sometimes light acts like a wave, and other times it behaves like a little particle. It's both. This week we discuss the experiments that demonstrate this, explain how scientists figured it all out in the first place. What does wave/particle duality have to do with astronomy? Well, everything, since light is the only way astronomers can see out into the Universe.

Episode 83: Wave Particle Duality


Ep. 80: Craters

  • March 17th, 2008
  • Show Notes
  • Comments(12)
  • Like it? Digg-it | Reddit | del.icio.us
Southward looking oblique view of Mare Imbrium and Copernicus crater on the Moon.
Southward looking oblique view of Mare Imbrium and Copernicus crater on the Moon. credit: NASA/Apollo 17

Pamela's attending the 39th Lunar and Planetary Sciences Conference, and you know what that means: the Moon… and planets! When you think of the Moon, you think of craters. In fact, that's a big theme this week at the conference, so Pamela took it as inspiration. Here you go, the week we drove the show into a crater. Wait… there's got to be a better way to describe this.

Episode 80: Craters (16.3MB)


Ep. 76: Lagrange Points

  • February 18th, 2008
  • Show Notes
  • Comments(3)
  • Like it? Digg-it | Reddit | del.icio.us
Joseph-Louis Lagrange
Joseph-Louis Lagrange credit: ESA

Gravity is always pulling you down, but there are places in the solar system where gravity balances out. These are called Lagrange points and space agencies use them as stable places to put spacecraft. Nature is on to them and has already been using them for billions of years.

Episode 76: Lagrange Points (13.2MB)


Ep. 74: Antimatter

  • February 4th, 2008
  • Show Notes
  • Comments(3)
  • Like it? Digg-it | Reddit | del.icio.us
ESA's Integral Space Observatory found a cloud of antimatter in the centre of our galaxy
ESA's Integral Space Observatory found a cloud of antimatter in the centre of our galaxy credit: NASA

Sometimes, we don’t get to decide what our show’s about. So many threads come together at the same time driving the decision for us. This is one of those situations. We’ve gotten so many questions from listeners in just the last week about antimatter that our show had just been chosen for it. You command, we obey. Let’s talk about antimatter.

Episode 74: Antimatter (15.4MB)


Ep. 73: Questions Show #8

  • January 28th, 2008
  • Show Notes
  • Comments(14)
  • Like it? Digg-it | Reddit | del.icio.us
Listener Questions Show
Listener Questions Show credit: Rebecca B-F

We’ve been so crazy following our own whims through the universe that we’ve neglected your questions. That ends today. It’s time to dig deep into our overflowing email box to retrieve the puzzling questions our listeners have sent in.

Episode 73: Questions Show #8 (16.8MB)


Ep. 72: Cosmic Rays

  • January 21st, 2008
  • Show Notes
  • Comments(2)
  • Like it? Digg-it | Reddit | del.icio.us
This active galaxy (3C442A) is emitting high-energy particles through its poles, as you can see with the xray/radio composite.
This active galaxy (3C442A) is emitting high-energy particles through its poles, as you can see with the xray/radio composite. credit: X-ray: NASA/CXC/Univ. of Bristol/Worrall et al.; Radio: NRAO/AUI/NSF

We’re going to return back to a long series of episodes we like to call: Radiation that Will Turn You Into a Superhero. This time we’re going to look at cosmic rays, which everyone knows made the Fantastic Four. These high-energy particles are streaming from the Sun and even intergalactic space, and do a wonderful job of destroying our DNA, giving us radiation sickness, and maybe (hopefully!) turning us into superheroes.

Episode 72: Cosmic Rays (13.3MB)


Ep. 69: The Large Hadron Collider and the Search for the Higgs-Boson

  • January 1st, 2008
  • Show Notes
  • Comments(4)
  • Like it? Digg-it | Reddit | del.icio.us
Artist's conception depicting the decay of a Higgs particle following a collision of two protons in the CMS experiment.
Artist's conception depicting the decay of a Higgs particle following a collision of two protons in the CMS experiment. credit: CERN/LHC

When it was first developed, the standard model predicted a collection of particles, and thanks to more and more powerful colliders, physicsists have been able to find them all except one: the Higgs-Boson. It's an important one because it should explain how objects have mass. The European Large Hadron Collider should have the power and sensitivity to find the Higgs-Boson.

Episode 69: The Large Hadron Collider and the Search for the Higgs-Boson (12.7MB)


Ep. 48: Tidal Forces Across the Universe

  • August 6th, 2007
  • Show Notes
  • Comments(0)
  • Like it? Digg-it | Reddit | del.icio.us
The gravity of the two colliding antennae galaxies creates the impressive tidal tails.
The gravity of the two colliding antennae galaxies creates the impressive tidal tails. credit: copyright Daniel Verschatse (Antilhue Observatory)

Last week we talked about tidal forces within our solar system. This week we're going to expand our view and encompass the entire universe. Some of the most dramatic events originate from tidal forces caused by gravity: other worlds, galaxies, black holes and even entire clusters of galaxies are under this influence.
 

Episode 48: Tidal Forces Across the Universe (12.2MB)
 


Ep. 47: Tidal Forces

  • July 30th, 2007
  • Show Notes
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The force of gravity can cause comets like Shoemaker-Levy 9 to rip apart
The force of gravity can cause comets like Shoemaker-Levy 9 to rip apart credit: H. Weaver (JHU), T. Smith, NASA

Consider the following: we've got tides here on Earth, the Moon only shows one face to the Earth, we've got volcanoes on Io, and ice geysers on Enceladus. All these phenomena originate from a common cause: the force of gravity stretching across space to tug at another world.

Episode 47: Tidal Forces (13.4MB)
 


Ep. 45: The Important Numbers in the Universe

  • July 16th, 2007
  • Show Notes
  • Comments(0)
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Numbers make the Universe go.
Numbers make the Universe go. credit: P. Gay

This week we wanted to give you a basic physics lesson. This isn't easy physics, this is a lesson on the basic numbers of the Universe. Each of these numbers define a key aspect of our Universe. If they had different values, the Universe would be a changed place, and life here on Earth would never have arisen.

Episode 45: The Important Numbers in the Universe (12.4MB)
 


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