All waves need a medium in order to travel true or false?

Answer 1

False, such as light, radio, and other electromagnetic waves.

The presence of any medium, in fact, slows down these waves. The speed of light through air is slower than the speed of light through empty space.

Answer 2

This was a very popular theory, the disproval of which stunned Michelson and Morley.

A common model of the Universe in the 1800s was that light traveled through a medium called the Luminiferous Aether. As the Earth rotates, and the Earth travels about the sun, and the sun orbits in our galaxy, and our galaxy hurtles among others, the absolute speed of a single point on the Earth's surface relative to the Aether must be ever-changing. Looking at it another way, if one could somehow perceive the "wind" of the Aether passing by, it would "blow" sometimes a wee bit stronger and in a different direction than at other times. If light is carried on this medium, then the perceived speed of light would be affected by the relative motion of this medium.

Airplanes and sound waves are carried through the air, and their speed changes with the wind, as observed on the ground.

So, people reasoned back then, a light beam that's traveling along with the "relative wind" of the Aether must travel at a different speed than a light beam that's traveling at right angles to the "wind" of the Aether. In particular, two beams of light traveling at right angles to each other would travel at a small difference in speed at certain times as the Earth turns. At that time, the speed of light could be measured very accurately, so accurately, in fact, that the difference in speed of light beams traveling in different directions through the Aether should have been observable, if one made very careful measurements.

So in 1887 Albert Michelson and Edward Morley devised a famous experiment to measure this difference in speed between two beams of light traveling at right angles to each other. Ultimately, they hoped with their apparatus to determine the absolute speed and direction of a given point on the Earth (the vector sum of all the different motions in various directions) through the Aether. There was much anticipation what the result might be.

They were stunned that they could measure no difference in the speeds of beams, no matter which directions they aimed them nor what time of day they tried the experiment. Light seemed to travel the same speed no matter in which direction, with respect to the Aether, the beams were aimed. His thoroughness in proving this point despite its intuitive absurdity earned Michelson the Nobel prize in 1907.

This result was a weird curiosity that made little sense to anybody until in 1905 Einstein came up with the Special Theory of Relativity, one component of which is that light, and hence all electromagnetic waves, require no medium at all! This is but one of several departures from intuition purported in Einstein's famous Theory. Yet Einstein's astonishing principles are the only way known (so far) to explain Michelson and Morley's experimental results. Since then, many more experiments have reinforced our collective acceptance of Einstein's counterintuitive postulates, so now we call them "facts," even though they are still amazing.

The Theory of Relativity is today widely accepted, at least among folks who give this subject a lot of thought. Electromagnetic waves (including radio, TV, cell phones, car key fobs, Bluetooth, Wi-Fi and light) require no medium. This makes it possible for astronauts to send radio messages through space, when space has (practically) nothing in it. We no longer need to postulate the Aether to explain to each other how light and radio waves can travel from the moon.

--Gil

Answer 3

false. quantum waves do not require a medium to propagate. it was theorised that a medium for light existed, called eather, however this was proven not to be fluid by Michelson. it can also be shown from Einstein's theory of special relativity that their is no attribute of eather which would influence the mechanics of the universe in any way, and therefore is assumed not to exist.

Answer 4

False. The majority of sunlight that reaches the Earth travels through a vacuum (empty space)

Answer 5

true