# Moving at the Speed of Light: Exploring Constant Velocity

• sirissa
In summary, the speed of light remains constant even when observed from a moving object, such as an airplane, due to the principles of relativity. This has been experimentally proven and forms the basis for many equations and theories.
sirissa
We know that light propagates in a constant speed c, but what if we are moving in an air plane and then turning on the light, why the speed of light remains constant?...
Thank u.

Velocities don't "add" the same way in relativity as they do in classical physics.

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/einvel.html

In the equation on the page above, let u' = c (velocity of the light with respect to the airplane) and see what you get for u (velocity of the light with respect to the ground).

The real answer is "because that's what experiment tells us". Everything else is derived from that.

## 1. What is the speed of light?

The speed of light, denoted by the symbol c, is approximately 299,792,458 meters per second in a vacuum. It is considered to be the fastest speed at which energy, information, or matter can travel.

## 2. How is constant velocity related to the speed of light?

Constant velocity refers to a constant speed and direction of motion. The speed of light is the ultimate constant velocity, as it does not change regardless of the observer's frame of reference. This is one of the fundamental principles of Einstein's theory of special relativity.

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

According to the theory of special relativity, nothing can travel faster than the speed of light. As an object approaches the speed of light, its mass and energy increase, making it impossible to reach or exceed the speed of light.

## 4. How do we measure the speed of light?

The speed of light is typically measured using a method called the Michelson-Morley experiment. This involves using a beam of light and reflecting it back and forth between two mirrors. By measuring the time it takes for the light to travel the distance between the mirrors, scientists can calculate the speed of light.

## 5. What are the practical implications of exploring constant velocity?

Studying constant velocity and the speed of light has many practical applications in various fields, including physics, astronomy, and telecommunications. It also helps us better understand the nature of space and time, and how objects behave at high velocities.

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