Messier 82 (Home of Cosmic Mysteries and Exploding Stars)

A mosaic image taken by the Hubble Telescope of Messier 82 (NASA, ca. 2000)

Twelve million light years from Earth lies Messier 82, a starburst galaxy 5 times more luminous than the entire Milky Way galaxy.  Messier 82 (AKA M82) is a very happening and dynamic galaxy: stars are being created there at an exceptionally high rate—most likely because the galaxy is “interacting” (or possibly colliding) with its neighboring galaxy M81. In 2005, the Hubble Space Telescope detected nearly 200 massive starburst clusters near M82’s center. Within these huge masses of dust and gas, stars are being birthed (and dying) at an astonishing rate.  The high energy released by this cosmic upheaval is nearly constant and the outflow of charged particles from M82 is evocatively known as “superwind”.

Lovell Telescope, Jodrell Bank Observatory (Mike Peel; Jodrell Bank Centre for Astrophysics, University of Manchester)

In 2010, astronomers working at Jodrell Bank Observatory in England discovered a mystery at the heart of M82: an unknown object was emitting high energy electromagnetic radiation in a pattern unlike anything else so far observed in the universe.  The mystery object appeared to be moving at 4 times the speed of light (which is, of course, quite impossible according to the standard model of the universe.  Newscientist.com offered the following explanation (of sorts) for the mystery object’s perceived velocity:

Such apparent “superluminal” motion has been seen before in high-speed jets of material squirted out by some black holes. The stuff in these jets is moving towards us at a slight angle and travelling at a fair fraction of the speed of light, and the effects of relativity produce a kind of optical illusion that makes the motion appear superluminal.

At present, the best explanation astronomers have for the mystery is that it is some sort of microquasar or black hole which is interacting in an unusual way with the tumultuous mass within a starburst cluster.  At present, the mystery is unexplained.

A super-dramatic before-and-after animation/photo of the type Ia supernova in M82

However, at present, M82 is doing entirely different things which have captured the attention of the international astronomy community.  On January 21^st, 2014, Steve Fossey and a group of his students at University College London spotted a colossal explosion within M82.  The event was quickly identified as a type Ia supernova, a bright and consistently energetic star explosion which occurs in binary stars where at least one star is a white dwarf (the dead, but energetic fragment of a larger star).   CBS News explains the phenomenon and its historical significance:

[When a] white dwarf siphons off too much mass from its companion star, a runaway nuclear reaction begins inside the dead star, leading to a brilliant supernova. Because Type Ia supernovas are believed to shine with equal brightness at their peaks, they are used as “standard candles” to measure distances the universe.

The supernova in M82 is the nearest supernova of its type observed since Supernova 1987A was spotted in February 1987 in the Large Magellanic Cloud (the dwarf galaxy which is companion to the Milky Way).  Telescopes around Earth are turning towards Ursa Major (where M82 is located in the sky).  Although the supernova is big news here, it is a very stale story in M82 where this all happened 12 million years ago.

An Artist’s Conception of a Type Ia Supernova