Changes

==Environment and Structure==

==Environment and Structure==

M82 was originally thought to be a type Irr II [[irregular galaxy]]. However, near-infrared photographs have shown two spiral arms.<ref name=constellation-guide>[http://www.constellation-guide.com/messier-82-cigar-galaxy/ Messier 82] from constellation-guide.com</ref> These had never been observed as the galaxy is viewed edge on from [[Earth]] and the arms are obscured by dust within the galaxy. In fact, it is the brightest galaxy in the night sky.<ref name=seds/>. It exhibits infrared excess, meaning that it emits more light in the infrared part of the [[electromagnetic spectrum|spectrum]] than in the visible. It is also classified as a starburst galaxy due to its incredibly high rate of star formation.

M82 was originally thought to be a type Irr II [[irregular galaxy]]. However, near-infrared photographs have shown two spiral arms.<ref name=constellation-guide>[http://www.constellation-guide.com/messier-82-cigar-galaxy/ Messier 82] from constellation-guide.com</ref> These had never been observed as the galaxy is viewed edge on from [[Earth]] and the arms are obscured by dust within the galaxy. In fact, it is the brightest galaxy in the night sky.<ref name=seds/> It exhibits infrared excess, meaning that it emits more light in the infrared part of the [[electromagnetic spectrum|spectrum]] than in the visible. It is also classified as a starburst galaxy due to its incredibly high rate of star formation.

The Cigar galaxy is approximately 38,000 [[light year]]s across, contains many dust lanes and roughly 30 billion stars.<ref name=seds/> The [[Hubble Space Telescope]] has found over a 100 [[globular cluster]]s in the Cigar galaxy as well as 197 star forming regions.<ref name=seds/><ref name=constellation-guide/> Star formation is believed to be at least 10 times that of the [[Milky Way]]. Three [[supernova|supernovae]] have also be observed. The supernova SN2014J, a type 1a, was one of the brightest supernovae observed in recent decades, reaching an apparent magnitude of 10.9.<ref name=constellation-guide/>

The Cigar galaxy is approximately 38,000 [[light year]]s across, contains many dust lanes and roughly 30 billion stars.<ref name=seds/> The [[Hubble Space Telescope]] has found over a 100 [[globular cluster]]s in the Cigar galaxy as well as 197 star forming regions.<ref name=seds/><ref name=constellation-guide/> Star formation is believed to be at least 10 times that of the [[Milky Way]]. Three [[supernova]]e have also be observed. The supernova SN2014J, a type 1a, was one of the brightest supernovae observed in recent decades, reaching an apparent magnitude of 10.9.<ref name=constellation-guide/>

M82 is situated about 150,000 light years from M81, also known as Bode's galaxy.<ref name=freeStarCharts/> The high volumes of star formation are due to tidal forces on M82, caused by its proximity to M81.

M82 is situated about 150,000 light years from M81, also known as Bode's galaxy.<ref name=freeStarCharts/> The high volumes of star formation are due to tidal forces on M82, caused by its proximity to M81.