Answer: Astronomers use the entire electromagnetic spectrum to observe a variety of things. Radio waves and microwaves – the longest wavelengths and lowest energies of light – are used to peer inside dense interstellar clouds and track the motion of cold, dark gas
To make a educational guess based on the your observations
A single reflection, like shouting at the side of a mountain and hearing
your voice come back to you, is an 'echo'.
Multiple reflection, like clapping your hands once inside a large room,
is 'reverberation'.
Answer:it takes approximately 148.8 seconds to achieve. The average person in a free-fall will hit the ground going at 9.66 m/s from the top of the Empire State Building.
Explanation: