Object Analysis

Messier 4 (M4) is a globular cluster in the constellation of Scorpius. It was discovered by Philippe Loys de Chéseaux in 1746 and cataloged by Charles Messier in 1764. It was the first globular cluster in which individual stars were resolved.

M4 is conspicuous in the skies, located just 1.3 degrees west of the bright star Antares. At a distance of 7,200 light-years, it is the closest globular cluster to our Solar System. Because of its proximity, it appears as a loose, grainy ball of light rather than a dense core, allowing even modest telescopes to resolve its stars.

The cluster is roughly 12.2 billion years old. One of its most interesting features is a "bar" structure of stars cutting through its center, visible in medium-sized telescopes. It also contains a pulsar (PSR B1620-26) with a white dwarf companion and a planet roughly 2.5 times the mass of Jupiter—the oldest known planet in the universe.