Knowra Interstellar medium Interstellar medium The matter and fields occupying the space between stars in a galaxy, including gas, dust, magnetic fields, and cosmic rays. It supplies material for star formation and is reshaped by stars.
Interstellar gas : Gas, mostly hydrogen and helium, distributed between stars in a galaxy. It makes up most of the medium’s ordinary matter and occurs in several physical states.
Stellar wind : A flow of charged particles continuously emitted by a star. Stellar winds inject energy and material into surrounding interstellar gas.
Big Bang nucleosynthesis : The production of the lightest atomic nuclei during the first minutes of the universe. It established the primordial hydrogen and helium from which early interstellar gas was made.
21-centimeter line : The radio spectral line emitted by neutral hydrogen through a hyperfine transition. Its emission maps atomic hydrogen across the Milky Way, including regions opaque to visible light.
Star formation : The process by which dense regions of gas collapse to form stars. The medium is both the reservoir from which stars form and the material their feedback alters.
Interstellar dust : Microscopic solid grains in space, made chiefly of silicates, carbon compounds, and ice. These grains absorb and scatter starlight while providing surfaces for molecule formation.
Supernova remnant : The expanding debris and shocked gas left by a supernova explosion. Supernovae heat, compress, and enrich the medium, driving much of its turbulence.
Stellar nucleosynthesis : The creation of chemical elements through nuclear reactions inside stars. Stars return newly made elements to the medium through winds and explosions.
Far-infrared astronomy : Astronomy using radiation at far-infrared wavelengths. Cold dust in the medium emits strongly in this band, revealing otherwise obscured material.
Initial mass function : The distribution of stellar masses at the birth of a population of stars. Conditions in star-forming interstellar gas influence which stellar masses are produced.
Show all 27