Earth's atmosphere blocks many types of light including gamma, x-rays most ultraviolet and infrared. So optical telescopes that use visible light and ultraviolet telescopes that are used to study very hot stars are much less effective on Earth.
Answer:
0.16Hz
Explanation:
wavelength (λ) = 125 meters
speed (V) = 20 m/s
frequency (F) = ?
Recall that frequency is the number of cycles the wave complete in one
second. And its value depends on the wavelength and speed of the wave.
So, apply the formula V = F λ
Make F the subject formula
F = V / λ
F = 20 m/s / 125 meters
F = 0.16 Hz
The spiral structure emerges when galactic clusters (open), H II regions and O & B type stars (young stars) are used as tracers. We know this to be true as other pinwheel galaxies exhibit the same patterns across these tracers as in the milky way.
1) Plates movement happens very slowly.
2) The earth's lithosphere is divided into pieces
3) they are caused by convection currents in the asthenosphere (upper mantle)
