Molecular clouds are dense regions of gas and dust in space, primarily composed of hydrogen molecules. They are the primary sites for star formation, providing the necessary material for stars to ignite and evolve. These clouds can be vast, spanning light-years, and are often cold and dark, making them difficult to observe directly. Within molecular clouds, various processes occur, including the formation of new stars and planetary systems. The presence of carbon monoxide and other molecules helps astronomers study these clouds, revealing their structure and dynamics. Understanding molecular clouds is crucial for comprehending the lifecycle of stars and the evolution of galaxies.