Object Analysis

Messier 100 (M100) is a grand design spiral galaxy in the constellation Coma Berenices. It is one of the brightest and largest galaxies in the Virgo Cluster, located about 55 million light-years away. Its well-defined, symmetrical spiral arms make it a quintessential example of galactic architecture.

The galaxy contains over 100 billion stars and is about 107,000 light-years in diameter. It has a high rate of star formation, particularly in its inner spiral arms, which are rich in blue star clusters and pink H II regions. M100 has been host to five observed supernovae in the last century.

Because it is a prominent member of the Virgo Cluster, M100 has been used as a "standard candle" to help determine the expansion rate of the universe. Observations of Cepheid variable stars in M100 by the Hubble Space Telescope were critical in refining our measurements of the Hubble Constant.