How Does Light Travel Through Space? Facts & FAQ

Last Updated on Mar 15 2024

Light is such a fundamental part of our lives. From the moment we’re born, we are showered with all kinds of electromagnetic radiation, both colorful, and invisible. Light travels through the vacuum of space at 186,828 miles per second as transverse waves, outside of any material or medium, because photons—the particles that make up light—also behave as waves. This is referred to as the wave-particle duality of light.  

What Is Light?

The wave-particle duality of light simply means that light behaves as both waves and particles. Although this has been long accepted as fact, scientists only managed to observe both these properties of light¹ simultaneously for the first time in 2015.

As a wave, light is electromagnetic radiation—vibrations, or oscillations, of the electric and magnetic fields. As particles, light is made up of little massless packets of energy called photons¹.

What Are Light Waves?

Waves are the transference of energy from one point to another. If we dropped a pebble into a small pond, the energy that the impact creates would transfer as a ripple, or a wave, that travels through the surface of the water, from one water particle to another, until eventually reaching the edge of the pond.

This is also how sound waves work—except that, with sound, it’s the pressure or vibrations of particles in the air that eventually reach our ears.

Unlike water and sound, light itself is electromagnetic radiation—or light waves—so it doesn’t need a medium to travel through.

What Are Transverse Waves?

Light propagates through transverse waves. Transverse waves refer to a way in which energy is transferred.

Transverse waves oscillate at a 90-degree angle (or right angle) to the direction the energy is traveling in. An easy way to picture this is to imagine an S shape flipped onto its side. The waves would be going up and down, while the energy would be moving either left or right.

With light waves¹, there are 2 oscillations to consider. If the light wave is traveling on the X axis, then the oscillations of the electric field would be at a right angle, either along the Y or Z axes, and the oscillations of the magnetic field would be on the other.

Can Anything Travel Faster Than Light?

The simple answer to this question is no, as far as we know at this time, nothing can go faster than the speed of light¹. Albert Einstein’s special theory of relativity states that “no known object can travel faster than the speed of light in a vacuum.”

Space and time don’t yet exist beyond the speed of light—if we were to travel that fast, the closer we get to the speed of light, the more our spatial dimension would shrink, until eventually collapsing.

Beyond this, the laws of physics state that as an object approaches the speed of light, its mass would become infinite, and so would the energy it would need to propel it. Since it’s probably impossible to create an infinite amount of energy, it would be difficult for anything to travel faster than light.

Tachyon, a hypothetical particle, is said to travel faster than the speed of light. However, because its speed would not be consistent with the known laws of physics, physicists believe that tachyon particles do not exist.

Final Thoughts

Light travels through space as transverse, electromagnetic waves. Its wave-particle duality means that it behaves as both particles and waves. As far as we know, nothing in the world travels as fast as light.

Featured Image Credit: NASA, Unsplash