Turkey Day

The Big Island had a 5.0 earthquake this morning. I hope to take a tour and check for damage.

2006 will be remembered by some as the year America's F-14 Tomcat was retired. The "Turkey," as it is affectionately called by aircrew, was in operation since 1974. This is an F-14A from squadron VF-84, with Carrier Air Wing 8 aboard USS Nimitz. The "Jolly Rogers" insignia made VF-84 a cool squadron to fly with. Anime fans, this was the inspiration for the markings in MACROSS. Aircraft from VF-84 appeared in THE FINAL COUNTDOWN with Kirk Douglas.

Naval aircrew (men and women) are distinguished by their aggressive personalities, their willingness to take and return flak, the insulting call signs they give each other, and their fondness for seeing things blow up.

The SWIFT spacecraft has found galaxy NGC 1316 to be full of supernovae. 4 Type Ia's have exploded there in 26 years, 2 in the last 5 months. SN 2006dd, circled at left, was detected on June 19 of this year. SN 2006mr to the right was detected a few days ago November 5. The bright spot at the centre is the galactic core. SWIFT allows us to catch stellar explosions on the fly.

Type Ia supernovae were thought to result from a white dwarf star acquiring mass from a stellar companion. When that mass passes a certain limit, an explosion is triggered. Because their masses are about the same limit, Type Ia's tend to have the same absolute magnitude of about -19.5. This allows them to be used as tests for cosmology.

Why NGC 1316 has so many Type Ia's is a mystery. Most galaxies have only 2-3 supernovae per century. It is highly unlikely that the conditions thought to cause Type Ia's could occur so many times in one galaxy. NGC 1316 has recently merged with another galaxy, which may have caused conditions producing Type Ia supernovae.

Redshifts of Type Ia supernovae are the only evidence for an "accelerating universe." The cosmic microwave background and large-scale structure tell us nothing about acceleration. The CMB dates from a redshift of 1000, far before any acceleration would have started. Supernova redshifts can be explained much more precisely by a changing speed of light.