Space and Solar Definitions - W

Watt, a measure of electrical power equal to potential in volts times current in amps.

Walking orbit

A spacecraft orbit that processes, wherein the location of periapsis changes with respect to the planet's surface in a useful way.

Wavelength

The distance that a wave from a single oscillation of electromagnetic radiation will propagate during the time required for one oscillation.

White Light (Wl)

Sunlight integrated over the visible portion of the spectrum (4000 - 7000 angstroms) so that all colors are blended to appear white to the eye.

White Light Flare

A major flare in which small parts become visible in white light. Such flares are usually strong x-ray, radio, and particle emitters.

Wolf Number

An historic term for sunspot number. In 1849, r. Wolf of zurich originated the general procedure for computing the sunspot number.