Questions Show: Spiral Arms, Seismic Waves on the Sun, and our Favorite Gear

Questions Shows | 9 comments

Artist illustration of the Milky Way

Artist illustration of the Milky Way

This week we explore galactic spiral arms, seismic quakes on the Sun, and our picks for astronomy gear. If you’ve got a question for the Astronomy Cast team, please email it in to and we’ll try to tackle it for a future show. Please include your location and a way to pronounce your name.

  • Spiral Arms, Seismic Waves on the Sun, and our Favorite Gear
  • Jump to Shownotes
  • Jump to Transcript or Download (coming soon!)
  • Shownotes

    Is there a traffic jam in spiral arms of galaxies?

    Why do seismic waves on the sun accelerate?

    What are Fraser’s and Pamela’s favorite astronomy gadgets?

    Why are the Pioneer spacecrafts slowing down?

    How can astronomers tell the distance of an object from red- and blue-shifting of light?

    Why are galaxies colliding if everything in the universe is moving away from everything else?

    On how much of the sun is fusion taking place?

    Why are globular clusters shaped the way they are?

    What is a parsec?

    • Answer:  3.26 lightyears
    • Parsec — World of Astronomy

    Meet up with Pamela and Chris Lintott at Mabel’s Tavern in London on Nov 23, 2008:  details


    1. Charles Kuester

      Great show, as usual.
      When it comes to gadgets for astronomy I found a great one that I could build myself for next to nothing. An image stabilizer for binoculars. Anything more than 7 or 8x is almost impossible to hold steady and I have an old pair of 10×50’s that I hardly ever used because of this. So when found this do-it yourself binocular stabilizer on the Sky & telescope website I built one. Find it here:
      It’s a little bulky and funny looking but It works great!

    2. Stephen

      Uhm, did a clearer explanation of the twin’s paradox get posted somewhere? In the old days, i was clear on this one, now i’m not.

    3. Tom Leach

      Did I hear correctly on your podcast that our Galaxy Milky Way is believed now to have only two arms? (the Orion Arm and the Saggitarius Arm?)

    4. AJenbo

      I keep getting an error when trying to listen to this show 🙁

    5. Roger

      I’m keep getting file errors to =(

    6. Stephen

      Pioneer anomaly. Last i heard, the Planetary Society funded a project to get the old tapes out, copy them to modern media, and start analysis. And, last i heard, about a third of the anomaly has been accounted for by thermal modeling of the space craft. No outgassing. The Pioneer anomaly is a very subtle effect, and would have been overwhelmed by anything so crude. There is simply more radiation going in one direction than another. Photons carry momentum.
      Gear. I like the new Newtonian Dobs with push-to computer locators. You get aperture per dollar like no other scope design can give you. Orion has a 10″ version that fits in your car, sets up including 2 star alignment in under 3 minutes in the dark and the cold, hardly ever needs collimation, the finder scope clips on and still doesn’t need alignment, and did i mention it’s 10″? And it’s $700.
      How could you possibly want a 76 mm doublet acromat for $1700 that still needs a mount? For $1600, you can get a Vixen 140 mm 4 element neo-acromat. It’s cheaper and nearly twice the aperture! And in no case will your mount fit in carry on.
      And yet there is a 10″ Newtonian dob that does fit in carry on. I’m not sure the Johnsonian is still made, however. And Sky & Tel ran an article about a home made 8″ that fits in carry on. These scopes include the mount, in carry on.
      But i’m having lots of fun with my laser pointer. Outreach has never been so easy. I know a guy who uses his laser pointer as his finder. He’s got it mount on the scope, and just moves the scope until the pointer is where the object is on the chart. I just got my scope mount and haven’t had a chance to try it out.

    7. AJenbo

      I sent an email to the AstronomyCast Team and the episode is now fixed 😀

    8. Izzy hope

      this website is coolness 🙂


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