Glossary of Radio Astronomy Terms
W
Wavelength:
The distance between two adjacent crests of a wave.
![Wavelength](https://public.nrao.edu/wp-content/uploads/2017/08/Screen-Shot-2017-08-01-at-10.46.51-AM-150x150.png)
Weakly Interacting Massive Particle (WIMP):
Short for “Weakly Interactive Massive Particle,” a WIMP is a hypothetical “dark matter” particle, which does not interact at all or very rarely with other particles via the electromagnetic force. It does, however, interact via gravitational effects.
Whirlpool galaxy:
A well-defined spiral galaxy with very prominent arms.
![Whirlpool galaxy](https://public.nrao.edu/wp-content/uploads/2017/01/M51multisqweb-150x150.jpg)
White dwarf:
A dying star that has collapsed to approximately the size of the Earth and is slowly cooling.
![White dwarf](https://public.nrao.edu/wp-content/uploads/2014/01/imagesnon-gallery2014d-finley01-05Triple_System_nrao-150x150.jpg)