Waves of vibrating electrons, freed by ultraviolet light from the sun, seem to be why radar beams bounce off the upper atmosphere (newscientist.com)
In fact, thanks to radar beams pinging off various solar - system bodies and to tracking of interplanetary spacecraft, the sun - Earth distance has been pegged with remarkable accuracy. (newscientist.com)
This one — standard on Denali and optional on SLT models — uses radar beams to keep high - tech eyes focused on the spots that yours may miss. (kbb.com)