Have you used a laser pointer before and wondered how fast the beam travels?
Laser beams are fast, and even if the beam disappears from our view, it is still there in space unless a solid mass blocks it.
However, the major question is whether a laser pointer is faster than light.
Einstein has proven that there is nothing faster than light in his relativity theories, and while many scientists have tried to prove him wrong, his theory is still relevant.
Some argue that laser beams can move faster than light.
Is that true?
The short answer is no. Again, nothing travels faster than the speed of light, but there are still ways that can make it seem like a laser beam is traveling faster.
Let’s find out more.
Is a Laser Faster Than Light?
The speed of light is close to 300,000 km/s, which is about 186,000 miles per second.
There have been videos and theories on the web that a laser can travel faster than that when shined at the moon.
This is where you flick the laser pointer across the surface of the moon in a hundredth of a second, a fairly easy thing to do. Here, according to the theories, the laser beam would move across the moon’s surface faster than the speed of light.
It is essential to note that it has been proven that nothing travels faster than the speed of light.
The photons, individual particles, emitting from the laser are indeed traveling to the moon at a similar speed as that of light.
However, they land side by side so rapidly that they end up creating a spot that can move faster than light. In reality, it is merely an illusion.
This method of clicking the laser beam in a certain way is one of the many ways to make it appear that a laser beam is moving faster than the speed of light.
Is The Flash Faster Than a Laser Beam?
The theory of relativity by Einstein imposed a cosmic speed limit that proves there is nothing that travels faster than the speed of light.
A flash of your camera results in a burst of light, which lasts for a fraction of a second.
The flash lasts somewhere between 1/1000 second or less.
If the shutter speed of your camera is at 1/50 second or 1/250 second, it will receive the fullest flash power.
The laser beam, on the other hand, lasts longer. The average power of a laser pointer is about 0.005 watts.
However, while the flash of a camera disappears instantly, the laser beam lasts until a solid mass blocks it.
This is also the reason why it is illegal to point a laser beam at the sky as it could interrupt the vision of the pilot of a flying plane.
Even if you can no longer see the laser beam with your naked eye, it travels fast and far in the sky.
This also shows that since a laser beam travels as fast as the speed of light, the flash is not faster than a laser beam.
How Fast is a Laser Pointer?
The laser point has an average power of around 0.005 watts.
However, since the laser beam has a narrow path, it can easily spread out over long distances.
When the beam is 100 meters away from the pointer, it is 100 times wider and can appear brighter than a 100-watt light bulb!
When the laser beam is seen from an airplane flying 40,000 feet in the air, the beam can look as bright as the light from a quarter of the moon, if there is no smog or clouds.
This is also a significant reason why it is illegal to point a laser pointer at an aircraft, as it can disrupt the pilot’s vision.
Lasers create tightly focused light, meaning it doesn’t spread out much over a long distance.
When using a laser pointer, the tiny spot can be seen across the room easily.
If you use it outside, the beam would appear brighter and bigger.
Moving further away, the beam would spread out and be undetectable from a distance.
The laser pointer is undoubtedly fast, but it is not as fast as the speed of light, even though there are ways to make it appear to be traveling faster than the speed of light.
Do Laser Pointers Go On Forever?
According to Newton’s first law of motion, the object will continue to stay in motion until an outside force acts upon it.
The beam from a laser, when pointed in space, would continue going on until it hits something.
You might not be able to detect the laser and assume it is gone, but the beam is tight enough to travel a greater distance than you would imagine.
While a typical laser pointer has merely five milliwatts, it still has the capability to hit the moon due to its tight beam.
It will, of course, spread over the surface once it reaches.
The atmosphere will distort the beam and absorb a little, but the light would still reach the space.
Laser beams can’t be stopped by other lights but can be stopped by matter.
This is the reason when you point the laser at a wall, the wall blocks it, but when you point it at the sky, it keeps going.
Even though there is gravity in space, the beam will continue to go on until it gets close enough to a matter, like a star or a planet, to absorb the light and stop it.
Therefore, many countries have made it illegal for people to point a laser pointer at the sky.
Vance is a dad, former software engineer, and tech lover. Knowing how a computer works becomes handy when he builds Pointer Clicker. His quest is to make tech more accessible for non-techie users. When not working with his team, you can find him caring for his son and gaming.
Wednesday 8th of June 2022
Thanks for the great article! Please explain this new claim: https://physicsworld.com/a/laser-smashes-light-speed-record/
"One of the most sacred laws of physics is that nothing can travel faster than the speed of light in vacuum. But this speed limit has been smashed in a recent experiment in which a laser pulse travels at more than 300 times the speed of light (L.J. Wang et al. 2000 Nature 406 277)."