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 firstname.lastname@example.org and we’ll try to tackle it for a future show. Please include your location and a way to pronounce your name.
Is there a traffic jam in spiral arms of galaxies?
- Abstract: Density Wave Theory of Galactic Spiral Arms (pdf)
- Density Wave Theory — Wiki
- Spiral Arms animation — Vanderbilt U
Why do seismic waves on the sun accelerate?
- Solar Flares Leave Sun Quaking — SOHO
- Movie of seismic waves on the sun — Stanford U
- Abstract: Properties of Flares-Generated Seismic Waves on the sun — arXiv
- Mythbusters: Helium and Sulfur Hexafloride — You Tube
What are Fraser’s and Pamela’s favorite astronomy gadgets?
- Fraser: Green laser pointer
- comparison of different brands
- Please be careful when using a green laser pointer!!
- Pamela: 1. Binoculars (a guide from Astronomy.com)
- 2. TelVue Pronto Telescope (a review)
- 3. Ritchey-Chretien telescopes
- CCD — wiki
- Reviews of different “Go-To” telescopes
Why are the Pioneer spacecrafts slowing down?
- Pioneer anomaly — Planetary Society
- Pioneer Anomaly, a deviation from Einstein Gravity? — Universe Today
- Pioneer Collaboration — ISSI
How can astronomers tell the distance of an object from red- and blue-shifting of light?
- Doppler shift –– UCLA
- Cepheid Variable Stars and Distance Determination — Australia Telescope Outreach and Ed.
- Measuring distances to stars
- The Cosmic Distance Scale and Standard Candles — UTK
- Cosmic Distance Ladder –– Wiki
- Andromeda/Milky Way collision — Hayden Planetarium
Why are galaxies colliding if everything in the universe is moving away from everything else?
- Colliding Galaxies — UTK
- How can galaxies collide in an expanding universe? — Cornell U
- What happens when galaxies collide? — Cornell U
On how much of the sun is fusion taking place?
- Answer: about 25%
- How the sun works — HowStuffWorks
- Convective zone — U of Michigan
- Radiative zone — U of Michgan
Why are globular clusters shaped the way they are?
- Globular Clusters — SEDS
- Globular Clusters: The Middle Ages — Star Stryder
- Abstract: Three Body Interactions of Black Holes in Globular clusters
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