Molekyylipilviksi

Molekyylipilviksi, also known as molecular clouds, are vast, cold, and dense regions of the interstellar medium composed primarily of molecular hydrogen. They are the birthplaces of stars and planets. These clouds are so cold, typically ranging from 10 to 30 Kelvin, that molecules can form and survive. The density within molecular clouds is significantly higher than the average interstellar medium, with particle densities of 100 to 100,000 particles per cubic centimeter.

Molecular clouds are difficult to observe directly in visible light because their dust content effectively obscures the light from background stars. Astronomers typically study them using radio and infrared telescopes, which can detect the faint emissions from molecules like carbon monoxide. These observations reveal the complex structures within molecular clouds, including filaments, clumps, and cores, which are the precursors to star formation. Gravitational collapse within denser regions of these clouds leads to the formation of protostars, which eventually ignite nuclear fusion and become stars. Subsequent accretion disks around these young stars can give rise to planetary systems.