# Light Beam Problem: What Will Happen?

• Temporarily Blah
In summary, the conversation is discussing the concept of light beams and their velocities in relation to each other. There is some confusion about what a photon would see and the role of time in relation to light. The conversation also touches on Einstein's theory of relativity and the idea that time is relative. Ultimately, the conclusion is that light beams cannot see and the concept of simultaneity is relative.
Temporarily Blah
Hello, I'm new, and I have a problem I can't seem to imagine to solve. Any help?

You have 5 light beams, moving from the same line, 1m apart from each other, all moving to the same target exactly 10 light seconds away. If each light beam sees the others move at light speed, will each light beam see the others hit first? Do they all hit first?

Simplified: What will each light beam see? What will an outside observer see?

Kinda confusing...

It's tough to say what a photon would see. Presumably time is irrelevant to a photon; it's at all of its destinations simultaneously. It seems that you are taking the postulate that all observers measures light's velocity at the speed of light, and applying that to light itself. But presumably that does not apply. The "observers" are assumed to be material (not photons).

Light beams do not see. I mean, even pretend-like. Objects (photons) moving at the speed of light do not experience time at all, thus one thing arriving before another is meaningless.

However, if an observer were flying at sublight speeds next to anyone of the beams, she will see the beam closest to her hit first, followed by beams father away hitting later.

Remember, seeing any event at a distance is seeing it in the past. An event happening 1m away is 1/300,000,000ths of a second old. An event 2m away is 2/300,000,000ths of a second old.

One of the major assertions of Einstein's theory is that we can no longer have an objective definition of simultaniety (i.e.: it's all relative).

The photon's null geodesics in our environment essentially say that there can exist no time dimension for photons, i.e., their physical environment is ours minus 1 dimension. This results in parallel moving photons standing still with respect to each other if observed from this 1-less-dimensional environment. Photons likewise can have relative velocities ranging from zero (parallel moving) to c (orthogonal paths) between each other. The dimension in the direction of motion may actually play the role of "time" dimension from the perspective of the "photonic observer".

You can not do such "see" when you imagine that you are riding on a light. I think it is because if you measure velocity of anything, you should use a period of time. But from the view point of a person outside the light, say, standing on the earth, he thinks the period of time takes infinity length of time.

Light does not have its own inertial reference frame, since the principle that the laws of physics should work the same way in all inertial frames would be violated by a coordinate system where a light wave was at rest. You can consider a sort of limiting case as v approaches c, but certain quantities don't converge to a well-defined limit as v approaches c, and the velocity of other light beams is one of them. See this thread for more discussion of this.

Light beams can't see. The observer is the one who needs light to see. This proves that all physical motion is absolute, not relative. Time is an illusion deduced from the motion of http://www.groupsrv.com/science/about96836-0-asc-0.html .

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## 1. What is the light beam problem?

The light beam problem is a thought experiment that explores the concept of a single particle of light (photon) being split into two beams and then recombined. It raises questions about the nature of light and the behavior of particles at the quantum level.

## 2. What will happen when the two beams are recombined?

According to the principles of quantum mechanics, the two beams will interfere with each other, creating a pattern of bright and dark spots depending on the relative phases of the beams. This phenomenon is known as interference and can be observed in experiments such as the double-slit experiment.

## 3. Can the two beams cancel each other out?

Yes, it is possible for the two beams to cancel each other out completely, resulting in a dark spot in the interference pattern. This occurs when the two beams have opposite phases and interfere destructively, leading to a cancellation of the light waves.

## 4. What does the light beam problem tell us about the nature of light?

The light beam problem highlights the wave-particle duality of light. While light is typically thought of as a wave, the interference observed in this thought experiment suggests that it also has particle-like properties. This duality is a fundamental concept in quantum mechanics and has been confirmed through numerous experiments.

## 5. How does the light beam problem relate to other areas of science?

The light beam problem is closely related to other areas of science such as quantum mechanics, optics, and particle physics. It has implications for our understanding of the behavior of particles at the quantum level and has led to the development of technologies such as quantum computing and cryptography.

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