ISM Vocab

5. The dimming of starlight by gas and dust in the interstellar medium
6. A cloud of glowing gas excited by ultraviolet radiation from hot stars
8. A graph that displays how much starlight is blocked by interstellar dust as a function of wavelength. The average size of interstellar grains can be inferred from these data
10. A nebula produced by starlight reflecting off dust particles in the interstellar medium
12. A region of high-temperature, low-density gas in the interstellar medium in which the Sun happens to be located
13. Extremely high-temperature, low-density gas in the interstellar medium
15. An interstellar gas cloud that is dense enough for the formation of molecules; discovered and studied through the radio emissions of such molecules

1. The hot, low-density gas between cooler clouds in the interstellar medium
2. A spectral line that does not occur in the laboratory because it depends on an atomic transition that is highly unlikely
3. Microscopic solid grains in the interstellar medium
4. The process in which dust scatters blue light out of starlight and makes the stars look redder
7. The gas and dust distributed between the stars
9. A nonluminous cloud of gas and dust visible because it blocks light from more distant stars and nebulae
11. Extremely high-temperature, low-density gas in the interstellar medium
14. A cloud of gas and dust in space