M100 is one of the brightest (magnitude 9.3) members of the Virgo group of galaxies. It is located to the north of Virgo in Coma Berenices, but still very much part of the Virgo group. It has many young, high temperature giant stars in the spiral arms giving them a predominantly blue colour. The shape has been heavily influenced by companion galaxies, three of which are visible in this image. It is estimated to be 60 million light years distant with a diameter of about 160,000 light years, and with a total mass of about 160 billion suns. NGC 4323, just to the bottom right of M100, is believed to be a satellite galaxy to M100.