Jul 16, 2008

The Pinwheel Galaxy


This is an image of the Pinwheel Galaxy. Beautiful. Isn't it? The Pinwheel Galaxy or Messier 101 or NGC 5457, is a face-on spiral galaxy situated at about 27 million light-years away in the constellation Ursa Major. Pinwheel Galaxy was discovered by Pierre M├ęchain on March 27, 1781, and he subsequently communicated his discovery to Charles Messier who verified its position and added it to the Messier Catalogue as one of the final entries.


The Pinwheel Galaxy is a relatively large galaxy compared to our Milky Way. With a diameter of 170,000 light-years it is nearly twice the size of the Milky Way. On photographs M101 can be seen to be asymmetrical on one side. It is thought that in the recent past (speaking in galactic terms) M101 underwent a near collision with another galaxy and the associated gravitational tidal forces caused the asymmetry.


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