Messier 4 is a globular cluster located in the constellation Scorpius. It is approximately 7,200 light-years away from Earth and is one of the closest globular clusters to our planet. Messier 4 contains hundreds of thousands of stars, with a notable population of red giants and a relatively low concentration of heavy elements. Discovered by Charles Messier in 1764, Messier 4 is best observed with binoculars or small telescopes. It has an apparent magnitude of about 5.9, making it visible to the naked eye under dark skies. The cluster is also known for its intriguing stellar population, including a number of variable stars.