The special theory of relativity, put forward by Albert Einstein in 1905, is still valid. explains how moving objects and light behave. The main assumption of the theory is that the speed of light is the same for every observer.

So how does this theory work for an observer in a car traveling at the speed of light (which is about 300,000 kilometers per second)? So when we’re in this car when we turn on the headlight Does the light stay behind us or does it shine before us?

To answer this question, you must first realize how special relativity works.

While this question may seem like a paradox at first, once we understand the basics of special relativity, we see that the question has a simple answer. According to special relativity; The observer in any vehicle, regardless of the speed at which it is traveling, as long as the vehicle is not accelerating (as long as it moves at a constant speed) yourself always”stands” Good “doesn’t movewill be detected.

For example, the rotation of the Earth around itself It is 350 m/s at the latitudes of Türkiye.. So every second you actually count 1, 2, 3 You move 350 meters! But we don’t feel like that at all, do we? Because the Earth always rotates “constantly” at this speed.

The second thing to realize is the phenomenon known as Doppler shift.

As we move at this speed, time slows down for us, lengths (wavelengths) shorten, masses increase, and colors change. These effects are time dilation, length shortening, mass gain and Doppler shift known as. All this is a result of the fact that the speed of light is constant for all observers, regardless of their motion.

So what does this mean for headlights?

Suppose you are in a car and you turn on the headlight. In this case you will see that your headlights illuminate normally for you. Because the light comes to you at the speed of light and illuminates everything in front of you. But in front of you if another car is traveling at the same speedwhen your headlights hit it not illuminated You will notice.

It is like that because, The reason is that both cars are experiencing time dilation and from your point of view, the other car’s clock is running slower than yours. In other words, it takes longer for the light reflected from the other car to reach your eyes than when both cars are stationary.

But what if you’re not in the car and standing on the side of the road? How would you see the car and its headlights?

The answer is very different. First of all, you see the car as very crooked and flattened due to its shortening. It will also appear very heavy and sluggish due to the increase in mass. The color shifts to the blue end of the spectrum due to Doppler shift.

What about the headlights? You see them as very bright and narrow beams of high-energy radiation, such as X-rays or gamma rays. This is due to the Doppler shift of the light from the headlights by a large factor. is a blue shift. Since the transverse components of the light’s momentum won’t change much compared to the longitudinal components, the beams will also be more focused along the car’s direction of travel.

So to summarize;

If you are in a car traveling at the speed of light and you turn on your headlights, from your point of view the headlights are you would see it works normallyHowever they would look very different to an outsider. If you were an outside observer watching a car traveling at the speed of light with the headlights on, you would see them very differently than they actually are.

Of course, this is all hypothetical and practical impossible. No matter how much energy you put into a car or any object with mass, it will never reach the speed of light. Only massless particles like photons can move at this speed. But it’s fun and educational to imagine what would happen if we crossed this boundary and explored the strange and wonderful world of relativity.