When the beam is meters away from the pointer, it is times wider and can appear brighter than a watt light bulb! When the laser beam is seen from an airplane flying 40, 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.
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. 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.
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. Save my name, email, and website in this browser for the next time I comment. This site uses Akismet to reduce spam. Enter e-mail address This e-mail address will be used to create your account. Reset your password. Please enter the e-mail address you used to register to reset your password Enter e-mail address. Registration complete. Lasers Research update Laser smashes light-speed record 19 Jul Want to read more?
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But according to Nemiroff, if you choose a finite point where the light should be, the beam must always be just beyond that point, one step closer to infinity.
In fact, the spot of light must always be in two places at once. Because the photon must be in two places at once, Nemiroff explained, something very bizarre happens: Two points of light appear on the wall, moving in opposite directions — one away from you and one toward you. One point of light is traveling more slowly than the speed of light, while the other appears to be moving faster.
As with the laser pointer projected onto the ceiling, this is an illusion. It is not a single photon traveling faster than the speed of light. This creates a burst of light, which Nemiroff calls a "photonic boom" because it is similar to the sonic boom that occurs when an object exceeds the speed of sound and overtakes sound waves. Nemiroff provided the technical details for this scenario in a paper that is now available on the preprint website arXiv.
In the paper, Nemiroff argues that these photonic booms exist in nature. Instead of a laser pointer, these photonic booms might be created by other bright sources of light like pulsars , which are collapsed stars that create very bright, steady beams of light. Rosanne Di Stefano of the Harvard-Smithsonian Center for Astrophysics, added in the statement: "The concept, although not proven in practice, is quite intriguing,".
Rather than an infinite wall, a photonic boom would appear when a beam of light moves across a spherical surface with depth contours, like Earth's moon, Nemiroff said. According to the statement, "details of the effect hinge on the interplay between the time it takes for a sweeping light beam to cross an object and the time it takes for the light beam to traverse the depth of the object. Measuring a photonic boom could reveal information about the object on which it appears.
According to the statement from Michigan Tech, a light beam could be swept across an asteroid's surface "thousands of times per second, with each sweep forcing a harmless but telling photonic boom.
According to Nemiroff, photonic booms could potentially be seen in NGC , also known as Hubble's Variable Nebula: a fan-shaped cloud of gas and dust that is illuminated by a single star at its base.
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