2016 Mar

How Does Light Travel

March 24, 2016

Speed of Light

The Cosmic Velocity Limit

Referring to Einstein’s unique relativity theory, the velocity of light is constant in a vacuum, and that can’t be exceeded by any object. In other words, nothing can travel at a speed higher than that of light. It’s the cosmic velocity limit for data exchange.

The speed of light has been measured to be 299,792,458 m/s. It’s the highest velocity that can be attained by any entity. As per now, no object has been discovered to travel at a velocity higher than the speed of light. A modern physics central pillar, the unique theory of relativity, shall be incorrect, if the speed of light is exceeded by any entity.

The Light’s Nature: Wave/Photons

One can comprehend the light travel phenomenon only after its nature is well understood. The initial foretastes of the nature of light had been presented by the creativity of James Clark Maxwell. It happened as an excellent revelation to him when he was coming up with a theory that describes the magnetic and electric forces between moving and stationary charged objects.

He found that magnetism and electricity were two sides of the exact same coin. As we have learnt during our H2 Physics tuition class, his concept combined magnetism and electricity into the unified electromagnetism force and light was discovered to be an electromagnetic wave. The theory explains light as a transverse wave which is electromagnetic, traveling through space.

On the other hand, light can be alternately seen as a particle, identified as a photon, if you look at it from the quantum mechanics perspective, which quantizes all energy and matter. Basically, in accordance to the quantum discipline, everything acts like a wave and a particle. Not only photons, but also electrons, which were at first believed to be particles, but now are acknowledged to behave as waves. The two, wave and particle viewpoints are equal, and for this discussion, we shall concentrate on the wave point of view, which offers a less complicated light travel explanation.

How Light Travels Via Space

As we know, each and every wave, waves something. This means that every wave travels via a medium, where it leads to disturbances and generates undulations. Light is an energy carrying electromagnetic wave. Maxwell found out how light travels via vacuum.

In vacuum, light travels in straight lines. Nevertheless, in a medium of material, light exhibits two properties of refraction and reflection. When a light wave travels within a medium, it gets refracted and when a light wave can’t penetrate an object, it‘s reflected back. When light travels via a medium, it intermingles with its electrical field. Based on that field’s nature, it’s possible to predict the degree of refraction or bending that light undergoes, when travelling through it.

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