Messier 4

Messier 4 or M4 (also known as or NGC 6121 the Spider Globular Cluster) is a globular cluster in the constellation of Scorpius. It is 6000 light years away from Earth. It is the closest globular cluster in the Milky Way  from Earth. It is 35 light-years in diameter. It contains more than 100,000 stars with a total mass equivalent to 800,000 solar masses.
Messier 4 is estimated to be 12.2 billion years old, making it the oldest globular cluster in the galaxy.

Messier 4 is one of the easiest globular clusters to find, being located only 1.3 degrees west from the bright star Antares.

 Notable Stars 
Images taken by the Hubble Space Telescope in 1995 found one of the oldest white dwarfs in our galaxy; 13 billion years old, the PSR B1620-26 is located in M4 and has one of the oldest planets in the galaxy

CX-1 is located in M4. it is a known as a possible pulsar binary

References

Category:Star clusters
Category:Milky Way