Sound waves in the early universe traveled faster than half of the speed of light.

Question

Quizplus · Accepted Answer

This is true. In the early universe, after the Big Bang, sound waves traveled at about 57% of the speed of light, which is more than half. This rapid expansion created the cosmic microwave background radiation that is observable today. This is true. In the early universe, the sound waves were traveling through a dense plasma that was tightly coupled to the radiation. This caused the sound waves to propagate at a speed that was determined by the properties of the plasma, and that speed was faster than half the speed of light. However, as the universe expanded and the plasma thinned out, the sound waves slowed down and eventually dissipated.

Sound Waves in the Early Universe Traveled Faster Than Half