how does electro magnetic waves propagate through free space?

Question

how can it travel in vacuum without any medium

Answer 1

Electric and magnetic fields don't need a medium. That's obvious because light and heat get here from the sun. As far as propagation goes, they consist of changing electric and magnetic fields. A changing electric field produces a changing magnetic field. That changing magnetic field creates and changing electric field etc....

Answer 2

Well, it isn't anything like sound wave or tidal wave which needs a medium to travel.

Magnetic waves are more like light rays, which do not need a medium to travel through.

Just think if the magnetic waves required a medium, how could planets revolve?
After all, planets revolve because of the magnetic pull (gravitational pull) of the sun and other planets.

But if you say that these waves do not travel through vacuum, how will all the planets stay stable?

They will collapse.

Answer 3

James Clerk Maxwell must have wondered about that, too. However, starting from Faraday's discoveries in electricity and magnetism, he slogged through the mathematics, and in 1864 he produced equations which proved that an electromagnetic wave would propagate through completely empty space. It doesn't need any kind of medium or carrier. You could say that, between the electricity and the magnetism, each manages somehow to be the medium for the other. But whatever you choose to say about it, Maxwell proved that it actually happened.

Answer 4

The old professor says: One of the problems of describing the nature of light is that it is done using quantum mechanics...in which there are no absolute answers to problems, just statistical indicators. A wave is defined as a disturbance in a medium. It is nature's way of transporting energy from one place to another. This led earlier scientists to try to find the medium. When they couldn't, they "invented" one and called it the aether. Every experiment you do to show light is a wave will indicate that it is indeed a wave phenomenon.

When we couldn't find the aether, we had to find another explanation. When experiments were done to show the "particle" nature of light, they too would give positive results and say "yes, light behaves like a particle". Actually "particle" is not a good word to use. We prefer to say a "quantum particle" or "discrete 'packet' of energy". The word quantum means quantity. It is something we can measure, but can't define. So, when one asks the question "Is light a wave or is it a photon?", the answer is "Yes". (a typical quantum physics response)

Anyway...if light is in its "photon" mood, it is energy...which has no mass or volume. Without mass, it can travel at "c" ,or the speed of light. Thus, we have come to the conclusion that light travels through space as photons and can take on electromagnetic properties when possible....or tested.

Answer 5

I hope that u can understand how a magnet placed in a perfect vacuum can attract magnetic material.Similarly an electrical charge placed in vacuum can excercise its effect of force(electrical field) over its surrounding space.Now electromagnetic waves are analogous to these two fields , then it becomes quiet natural for it to propagate through empty space.
Another way of thinking it may make it more meaningful.dont think it as a wave but think it as a particle.A ball can very easily travel through free space when thrown.If i am correct take it to ur brain,else throw it in ur trash...

Answer 6

1. Electromagnetic (EM) radiation is a self-propagating wave in space with electric and magnetic components. These components oscillate at right angles to each other and to the direction of propagation, and are in phase with each other. Electromagnetic radiation is classified into types according to the frequency of the wave: these types include, in order of increasing frequency, radio waves, microwaves, terahertz radiation, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays. In some technical contexts the entire range is referred to as just 'light'.

EM radiation carries energy and momentum, which may be imparted when it interacts with matter.

2. Propagation of waves in free-space is different from that in cable or waveguides. With respect to signal propagation, these latter are one-dimensional systems, and a wave does not lose energy as it travels, except that due to absorption or scattering. In three-dimensions waves radiate spherically. As they travel, the surface area they occupy increases as the square of the distance traveled. However, since energy is conserved, the energy per unit surface area must decrease as the square of the distance. Thus the power of free-space waves obey an inverse square law. For each doubling of the distance between the source and receiver, a 6dB loss is experienced. For all frequencies up to millimetre-wave frequencies, this free-space loss is the most important source of loss. Because of it, free-space systems usually require much more power than cable or fibre systems.

Answer 7

I think people get mixed up with their understanding of the wave. Ok you see a wave on the sea.you see a lump moving across the surface. Now for a electromagnetic wave you are looking at a rise and fall of energy. The wave formation can be seen on an oscilloscope, but not physically on the electro magnetic energy.

Answer 8

By a wave motion.

No medium means no resistance, so it is not absorb much, does not loose too much amplitude also.

But.

There is no such thing as total vacuum, space has ether.

High vacuum is measured in terms of ten to the negative power multiplied by 1 atmosphere, the units are Torre {named after Torricelli an Italian scientist}.

Answer 9

The medium is the electric and magnetic field. Alternately, in quantum mechanics, light is a particle, but a particle with no mass, only energy. And the energy is not related to the speed, it is related to the wavelength. Wavelength of a particle? And a particle with no mass? That is right. Quantum mechanics is really weird.

Answer 10

It doesn't need a medium, that's one of the ways in which they behave more like particles than waves.