# Light Speed Separation: How Long?

• joruz1
In summary, if two objects move away from each other in opposite colinear directions at the speed of light, it would be an impossible situation as nothing can travel at the speed of light except light itself. If the objects are moving slightly slower than the speed of light, the time it takes for light to travel from one object to the other would depend on the speeds of both objects and the distance between them at the time of emission.
joruz1
If two objects move away from each other in opposite colinear directions at the speed of light. How long will it take for the light from one of the objects to reach the other?

I think the answer is never, but not sure.

If you mean that each object is moving at exactly the speed of light, then your question starts out with a impossible situation, because nothing can travel at the speed of light (except light itself, of course). There is no way to answer this question in its literal form.

If each object is moving very slightly slower than the speed of light, then an answer is possible in principle, but you don't provide enough information to calculate it. The time it takes for light to travel from one object to the other depends on the speeds of both objects, and on how far apart they are when the first object emits the light.

You are correct, the light from one object will never reach the other if they are moving away from each other at the speed of light. This is because according to Einstein's theory of relativity, as an object approaches the speed of light, time slows down for that object. This means that for an outside observer, the time it takes for the light to travel from one object to the other would also slow down, making it impossible for the light to ever reach the other object. This concept is known as time dilation and is a fundamental principle in our understanding of the universe.

## 1. How is light speed measured?

Light speed is measured by using the universally accepted speed of light in a vacuum, which is approximately 299,792,458 meters per second. This measurement is based on the distance light can travel in one second.

## 2. What is light speed separation?

Light speed separation is the concept of separating objects based on their velocity, specifically their speed relative to the speed of light. This separation can occur in various mediums, such as air or water, and is an important concept in understanding the behavior of light.

## 3. Can any object reach the speed of light?

According to Einstein's theory of relativity, no object with mass can reach the speed of light. As an object approaches the speed of light, its mass increases infinitely and would require an infinite amount of energy to continue accelerating.

## 4. How long does it take for light to travel across the universe?

The exact time it takes for light to travel across the universe is difficult to determine due to the constantly expanding size of the universe. However, based on current estimates, it would take approximately 46.5 billion years for light to travel from one end of the observable universe to the other.

## 5. Can light speed separation be observed in everyday life?

Yes, light speed separation can be observed in everyday life. For example, when you see a rainbow, the colors are separated based on their different speeds of light through water droplets in the air. Also, the colors of a prism are separated due to the different speeds of light through the different angles of the prism.

• Special and General Relativity
Replies
16
Views
1K
• Special and General Relativity
Replies
12
Views
2K
• Special and General Relativity
Replies
13
Views
1K
• Special and General Relativity
Replies
33
Views
2K
• Special and General Relativity
Replies
21
Views
484
• Special and General Relativity
Replies
25
Views
3K
• Special and General Relativity
Replies
2
Views
460
• Special and General Relativity
Replies
3
Views
984
• Special and General Relativity
Replies
45
Views
3K
• Special and General Relativity
Replies
5
Views
1K