Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
3 Cards in this Set
- Front
- Back
What is the most abundant element in the intersellar medium?
|
Hydrogen
|
|
What is 21 cm radiation?
|
The electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms.
|
|
Reddening
|
Dimming of starlight by interstellar matter, which tends to scatter higher-frequency components of the radiation more efficiently than the lower-frequency components.
|