# Speed of Light Thought Experiment

• Jopus Foghlu
There is a thought experiment about the speed of light involving a tube around the Earth's circumference, snooker balls, and a super powerful pushing arm. The experiment shows that information can be transmitted faster than light, but it is missing the fact that the speed of sound in snooker balls is much slower than the speed of light. This means that the ball popping out in one second is not actually transmitting information faster than light. This misconception is a common one, with many people asking about it on forums.
Jopus Foghlu
A thought experiment about the speed of light. Say I build a 600,000 km long tube around the circumference of the Earth at the Equator. The tube's inner diameter is constant at 54.4505 mm. A snooker ball is perfectly manufactured to its lowest tolerance by a special new machine. Each one is 54.4501 mm in diameter. I fill said tube with snooker balls (btw the tube wraps around Earth's circumference at the Equator approximately 25 times, so there are approximately 11,440,000,000 of them. I have assumed light travels 300,000 km every second. I am also in possession of a super powerful pushing arm with Giga-tonnes of pushing power, which is needed even though the tube is frictionless due to the sheer number of snooker balls it needs to displace. 25 diameters up from where I start pushing, a ball pops out in 1 second. The 'signal' necessary for it to do so has just traveled 600,000 km in one second. Yet light can only travel half that distance in the same time. Voila! Faster than light information transmission. Okay, what am I missing if anything?

Jopus Foghlu said:
Okay, what am I missing if anything?

Yes you are missing something. What is the speed of sound in snooker balls?

Welcome to the PF, BTW.

Last edited:
tech99 and rootone

rootone and berkeman
@Jopus Foghlu don't feel bad. We've had probably several hundred people come here and ask that so you're not alone in your misconception.

Props for creativity though!

## What is the speed of light thought experiment?

The speed of light thought experiment is a hypothetical scenario used to explore the implications of Einstein's theory of special relativity. It involves imagining a person traveling away from Earth at the speed of light and the effects this would have on their perception of time and space.

## How does the speed of light thought experiment relate to Einstein's theory of relativity?

The speed of light thought experiment is a way to understand and visualize the principles of Einstein's theory of special relativity. It demonstrates how the laws of physics, particularly the speed of light, are constant and how time and space are relative to the observer's frame of reference.

## Can the speed of light thought experiment actually be tested?

No, the speed of light thought experiment is purely theoretical and cannot be tested in real life. However, the principles and predictions of Einstein's theory of special relativity have been extensively tested and confirmed through experiments such as the Michelson-Morley experiment and the measurement of time dilation in particle accelerators.

## What are some common misconceptions about the speed of light thought experiment?

One common misconception is that the speed of light is the fastest possible speed. In reality, the speed of light is the fastest speed at which energy can travel through space, but there are other things that can travel faster, such as the expansion of the universe. Another misconception is that the speed of light applies only to light itself, when in fact it is a fundamental constant that applies to all forms of energy.

## What practical applications does the speed of light thought experiment have?

While the speed of light thought experiment may not have any direct practical applications, it has greatly influenced our understanding of the universe and has led to the development of technologies such as GPS systems, which rely on the principles of special relativity to function accurately. It also has implications for space travel and the potential for faster-than-light travel in the future.

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