# Why Do Photons Travel at the Speed of Light?

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This is an interesting question that I can't seem to sort out. Since photons are massless, they travel at the speed of light(3*10^8 m/s). Why must photons travel at the highest possible speed (the speed of light)? Why is it when a photon is created, it doesn't start off at a speed zero and then once a force(whatever the magnitude) is acted upon it cause it to move at the speed of light? How could this happen?

Thanks! Well, if that bothers you (I don't see WHY it should bother you - you could just as well ask why massive objects DO accelerate, right ?), think of photons as having a very very tiny mass. They will then accelerate as you propose, but they will do so extremely swiftly, so that the time for them to "get up speed" is very small. Their speed will then by a tiny tiny fraction below light velocity, but that will not be noticeable. Now think of them to be "lighter and lighter". In the end, there is no observable phenomenon that will be noticeably different from the photons without any mass.

## 1. Why do photons travel at the speed of light?

Photons travel at the speed of light because they have no mass. According to Einstein's theory of relativity, objects with mass cannot reach the speed of light because it would require an infinite amount of energy. Since photons have no mass, they are able to travel at the speed of light.

## 2. How do we know that photons travel at the speed of light?

The speed of light has been measured and confirmed using various methods, such as the Michelson-Morley experiment and the measurement of the speed of light in a vacuum. These experiments have consistently shown that the speed of light is approximately 299,792,458 meters per second, which is the same speed at which photons travel.

## 3. Can anything travel faster than the speed of light?

According to the theory of relativity, nothing can travel faster than the speed of light. This is because as an object approaches the speed of light, its mass increases and it requires more energy to accelerate it further. Therefore, it is impossible for any object with mass to reach or exceed the speed of light.

## 4. How does the speed of light affect our perception of time?

The speed of light is considered a universal constant and is used as a fundamental component in the equations of special relativity. One of the consequences of this is time dilation, where time appears to pass slower for objects moving at high speeds. This means that as an object approaches the speed of light, time slows down for that object.

## 5. Are there any exceptions to the rule that photons travel at the speed of light?

There are no known exceptions to this rule. Photons have been observed traveling at the speed of light in all experiments and observations. However, there are theories, such as the string theory, that propose the existence of particles called "tachyons" which could potentially travel faster than the speed of light. However, this is currently only a theoretical concept and has not been proven or observed.