# Can Push Travel Faster Than Light?

• B
• PCNerdz
In summary, the distance the light would travel is directly proportional to the speed of sound in the rod.
PCNerdz
TL;DR Summary
Lightyear long pole, button activates light on the other end. How long does it take to reach you?
Been thinking about this since I was 12. Suppose you had a 1 lightyear long pole, and on the other end was a button 1 inch away that activates a light. The light is powerful enough for you to see it 1 lightyear away. You push the pole 1 inch forward. How long does it take for the light to reach you? Would you even be able to push the pole 1 inch?

My guess is it all depends on the speed of push, so anywhere from 2 years to many centuries, and it depends on how the pole is set up for the 2nd Question. We will say Gravity, Friction, air resistance and all that is negligible to help simplify it. An isolated system.

I think this requires you to know the speed of push, but I can’t find much on the internet on that subject. An exact answer would be great, but I’m mainly trying to create a discussion to see what some of you think about it.

Welcome to PF.
It actually depends largely on the speed of sound in the pole.

It would be roughly the length divided by the speed of sound in the rod plus one year.

PCNerdz said:
I think this requires you to know the speed of push, but I can’t find much on the internet on that subject.
When you push on one end of the rod, the other end doesn't instantaneously move. It takes a while for the push to travel. This push is just a sound wave pulse.

sophiecentaur
Thanks, I didn’t know the “speed of push” had to do with the speed of sound. This has been in the back of my mind for years as a question I wasn’t sure if I would ever find the answer to. I learned something new today. Thank you for taking the time to reply, have a good day.

scottdave and sophiecentaur
Mister T said:
When you push on one end of the rod, the other end doesn't instantaneously move. It takes a while for the push to travel. This push is just a sound wave pulse.
These things need to be said.

## What is the speed of push?

The speed of push refers to the speed at which a force is applied to an object, causing it to move. It is dependent on the strength and direction of the force, as well as the mass and resistance of the object being pushed.

## What is the speed of light?

The speed of light is a fundamental constant in physics, denoted by the symbol c. It is the speed at which light travels in a vacuum, approximately 299,792,458 meters per second.

## Is the speed of push faster than the speed of light?

No, the speed of light is the fastest speed at which any object or information can travel in the universe. The speed of push is limited by the physical properties of the object being pushed, and cannot exceed the speed of light.

## How does the speed of push compare to the speed of light?

The speed of push is significantly slower than the speed of light. For example, the fastest human sprinters can reach speeds of around 10 meters per second, while light travels at nearly 300 million meters per second.

## Can the speed of push affect the speed of light?

No, the speed of push and the speed of light are independent of each other. The speed of light is a constant, while the speed of push can be altered by changing the force or resistance involved. However, the speed of light can be affected by other factors such as gravity and the medium through which it is traveling.

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