•charged particles (electrons, protons) and carry electric field, strength of field µ 1/d2
•collision or heating ® particle vibration ® change in field ® change in
electrical forces on other particles
•change in electrical forces ® information about original particle
•®information transmitted through a
disturbance (change in
electrical field)
•magnetic field associated with electrical field
•®electromagnetic
waves
•Electromagnetic waves
from moving charged particles
•in astronomical objects
•propagate at speed of light, c (need not be visible)
•