36 Galactic Mile Posts

These 36 galaxies are some of the 40+ that have been observed by astronomers using the Hubble Space Telescope because they contain both Cepheid variable stars and supernovae. These stars are used measure the distance and refine the measurement of the rate of the expansion of the universe. Pictured above (from left to right and top to bottom) are NGC 7541, NGC 3021, NGC 5643, NGC 3254, NGC 3147, NGC 105, NGC 2608, NGC 3583, NGC 3147, Mrk 1337, NGC 5861, NGC 2525, NGC 1015, UGC 9391, NGC 691, NGC 7678, NGC 2442, NGC 5468, NGC 5917, NGC 4639, NGC 3972, The Antennae Galaxies, NGC 5584, M106, NGC 7250, NGC 3370, NGC 5728, NGC 4424, NGC 1559, NGC 3982, NGC 1448, NGC 4680, M101, NGC 1365, NGC 7329, and NGC 3447.

Image Credits: NASA / ESA / STScI

The Fireworks Galaxy

NGC 6946 is known as the Fireworks Galaxy, In the past century, nine supernovae have been observed to explode in its spiral arms. This makes it the most prolific known galaxy for this type of event over a period of 100 years. By comparison, the Milky Way galaxy, which has twice as many stars as NGC 6946, averages one supernova event per century.

Image Credits: NASA, ESA, STScI, R. Gendler, and the Subaru Telescope (NAOJ)

A Supernova Factory

ngc 1448This is the spiral galaxy NGC 1448 which has a prominent disc of very bright, young stars surrounding its small core. Recently, this galaxy has recently been a prolific factory of supernovae, the dramatic explosions that mark the death of stars—one was observed in 1983, and two more have been discovered since the turn of the century.

Image Credit: ESO

A Supernova

NGC 6984Supernovae are incredibly bright. They are formed as a star reaches the end of its life with a dramatic explosion, expelling most of its material out into space. This Hubble image of spiral galaxy NGC 6984 shows supernova SN 2013ek. It’s the bright spot just slightly above and to the right of the galaxy’s center. There was another supernova (2012im) last year is this same galaxy.

Image Credit: NASA