Tähtedevaheline

Tähtedevaheline, meaning "interstellar" in Estonian, refers to the space between stars. This vast expanse is not entirely empty but contains a tenuous medium known as the interstellar medium (ISM). The ISM is composed primarily of gas and dust. The gas is mostly hydrogen and helium, with trace amounts of heavier elements, existing in various states of ionization and temperature. The dust grains, typically composed of silicates and carbon compounds, are much smaller than the wavelength of visible light but can scatter and absorb starlight, leading to observable phenomena like dark nebulae.

Within the interstellar medium, stars are born from the gravitational collapse of denser regions within molecular clouds, which are the coldest and densest parts of the ISM. Stars then spend the majority of their lives within this medium, interacting with it through stellar winds and radiation. When stars reach the end of their lives, they can enrich the ISM with heavier elements created through nucleosynthesis, seeding the next generation of stars and planets. The study of the interstellar medium is crucial for understanding star formation, galactic evolution, and the chemical composition of the universe. Phenomena like nebulae, supernova remnants, and pulsars are all observable manifestations of processes occurring within or interacting with the interstellar space.