Definition of perk. intransitive verb. 1a : to thrust up the head, stretch out the neck, or carry the body in a bold or insolent mannerb : to stick up or out jauntily. 2 : to gain in vigor or cheerfulness especially after a period of weakness or depression âusually used with up he's perked up noticeably.
Quick Answer. Light travels at a considerably higher speed than sound. Light travels at a constant speed of 186,000 miles per second, but the speed of sound is only 761.2 mph.
Since we know that the speed of light is around 300,000 kilometers per second, it is easy to calculate how far away two galaxies must be in order to be moving away from each other faster than the speed of light.