The Mystery of Light and Theory of Relativity

Up to 19th century scientist believed they were close enough to complete the missing puzzle in the cosmos. Since sound waves require some medium to travel one point to another, scientist thought light wave also required similar kind of medium. Based on the same idea they understood that the entire universe is filled with some strange medium called the ether. So they used this ether to explain the behaviors of electromagnetic waves. This sounds so strange.
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