M8      The Lagoon Nebula in Sagittarius (NGC 6523)

        Object type:             Emission (H II region) nebula

        Distance from Earth:      4000 light years / 1200 parsecs

        Distance across Nebula:   30 light years / 9.2 parsecs


        The Lagoon Nebula is mainly hydrogen gas left over from the star
        formation of NGC 6530, a star cluster near the middle of the
        Lagoon.  The expanding gas collides with dark matter nearby, making
        bright rims of gas surrounded by dark clouds.  One dark cloud cuts
        across the middle of the nebula, making it look like a lagoon.  The
        nebula is approximately 2 million years old, which is considered
        young on a cosmic scale. 