# Barber's pole - appear faster than light?

• kyle1320
In summary, the speed of the circumference of a massless barber's pole can appear to be greater than the speed of light, as seen from a different reference frame, but this does not violate the law of relativity as no physical object is actually moving faster than the speed of light. This is similar to the concept of a flashlight pointing from the Moon to Ceres, where the imaginary beam appears to travel faster than the speed of light, but no actual information or object is being transmitted at superluminal speeds.
kyle1320
Hi, so imagine this: You have (for this theoretical situation) an entirely massless barber's pole. When it spins, the speed of the of the circumference of the pole is less than the speed the line appears to travel up (or down) the side of the barber's pole. If you were to spin the pole, could the line traveling up the pole appear to go faster than light, even though no physical part of the pole is traveling faster? Disregarding red / blue shift.

Welcome to PF, Kyle. Nothing physical is moving faster than c. It's the same idea as the spot of a searchlight sweeping at superluminal speed. The law of relativity states that no information can be transmitted at or above c; that is not violated by the circumstance in question.

kyle1320 said:
could the line traveling up the pole appear to go faster than light, even though no physical part of the pole is traveling faster?
It could. Just as if I pointed a flashlight at the Moon, then whipped it around to point it at Ceres.

The "beam" gets from Moon to Ceres - a distance of hunderds of millions of miles - in a fraction of a second.

Of course, the beam is no more a real thing than the imaginary line you attribute to points on the barber pole.

## 1. How does the Barber's pole appear to move faster than light?

The Barber's pole illusion is created by the rotation of a striped pole against a stationary background. The stripes are spaced in a way that creates a false perception of motion, making the pole appear to move faster than light.

## 2. Is the Barber's pole actually moving faster than light?

No, the Barber's pole is not actually moving faster than light. It is an optical illusion caused by the specific design of the stripes and the rotation of the pole.

## 3. Can the Barber's pole illusion be recreated with any striped pattern?

Yes, the illusion can be recreated with any striped pattern as long as the stripes are equally spaced and the object is rotating against a stationary background.

## 4. Are there any scientific explanations for the Barber's pole illusion?

The Barber's pole illusion falls under the category of motion illusions, which are caused by the brain's inability to accurately process visual information. It is a result of the brain trying to make sense of conflicting visual cues.

## 5. Can the Barber's pole illusion be used in research or experiments?

Yes, the Barber's pole illusion can be used in research and experiments to study how the brain processes visual information and how illusions can be used to understand perception and cognition.

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