COMMENTS ON THE SUBJECT :

M100 is a spiral galaxy, seen exactly from above, located in the Chevelure de Bérénice. It was discovered in 1781 by Pierre Méchain and included by his friend Charles Messier in his catalogue a few weeks later.

Thanks to the discovery of 20 Cepheid stars by the Hubble Space Telescope in 1993, the distance of the galaxy was estimated at 56 million light years. It was M100 that served as a test for the space telescope and showed its optical defects at the beginning of the mission. The galaxy is located in the Virgo cluster, of which it is one of the main components along with M87. Its brightest spiral arms are filled with blue stars resulting from the interaction of the galaxy with neighbouring galaxies. The diameter of the galaxy is larger than that of the Milky Way, at about 120 000 light years.

During the 20th century, no less than four supernovas were recorded in the galaxy: 1901B, 1914A, 1959E and 1979C, which reached a magnitude of 11.6 in April 1979, which is rare for such a distant galaxy.