molekyylipilven

Molekyylipilven, also known as molecular cloud, is a type of interstellar cloud composed primarily of hydrogen, along with helium and trace amounts of heavier elements. These clouds are the birthplaces of stars and planetary systems. Molecular clouds are typically found in the spiral arms of galaxies, including our own Milky Way. They are characterized by their low temperatures, typically around 10-20 Kelvin, and their high densities, which can reach up to 10^6 particles per cubic centimeter.

Molecular clouds are primarily composed of molecular hydrogen (H2), which is difficult to detect directly due to its lack of a permanent dipole moment. Instead, astronomers often observe other molecules, such as carbon monoxide (CO), which is a good tracer of molecular hydrogen. These clouds can span hundreds of light-years in size and contain enough material to form thousands of stars.

The formation of molecular clouds is closely linked to the process of star formation. As interstellar gas cools and condenses, it can form dense cores within these clouds, which eventually collapse under their own gravity to form protostars. These protostars can then grow into main-sequence stars, potentially accompanied by planetary systems.

Molecular clouds play a crucial role in the chemical evolution of the universe. They are the sites where complex molecules, including organic compounds, are formed. These molecules can then be incorporated into planetary systems, potentially influencing the development of life as we know it.