Can you shine a laser at the moon

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One of the experiments taken into space on Apollo 11 was called the Lunar Laser Retro-Reflector, and it still works even today though perhaps not as well as it did , just like it did in a episode of "The Big Bang Theory. Under those circumstances, it turns out Earth still catches fire. The reflected light from the Moon would be four thousand times brighter than the noonday sun.

The laser itself would exert enough radiation pressure to accelerate the Moon at about one ten millionth of a gee. The surface layer of the Moon becomes a plasma, but that plasma is still blocking the path of the beam.

Our laser keeps pouring more and more energy into the plasma, and the plasma keeps getting hotter and hotter. The particles bounce off each other, slam into the surface of the Moon, and eventually blast away into space at a terrific speed. This flow of material effectively turns the entire surface of the Moon into a rocket engine—and a surprisingly efficient one, too. Using lasers to blast off surface material like this is called laser ablation, and it turns out to be a promising method for spacecraft propulsion.

The Moon is massive, but slowly and surely the rock plasma jet begins to push it away from the Earth. But if we make the wild guess that the particles in the plasma exit at an average speed of kilometers per second, then it will take a few months for the Moon to be pushed out of range of our laser.

It's like waving a garden hose back and forth. Here you are not talking about speed of light; you are talking about speed of flicking of wrist. So it should be much smaller. But also it took mere seconds for me to do so and the distance is also big. So the speed should be a big number. And this number's reciprocal is the speed by which the point moved. It is impossible to break the speed of light for a simple reason.

The speed of light depends on the properties of empty space- permittivity and permeability values alone. Empty space has to change character before the speed of light is changed. This by the way is general for any wave motion and the present confusion could be comming from imagining light as particles.. The photon is not a particle, it is the probability of finding energy in a certain point- Otherwise you run into all sorts of difficulties like the size of a photon of extreemely long wavelenghts for example.

So even in sound waves in a homogeneous medium it is impossible for sound to exceed the speed of sound determined by the medium properties. Motion of objects producing and receiving sound can only change the frequency of it. The speed of sound can be truly changed only if the medium as a whole moves. Which in the case of light requires vacuum itself to move, which is unheard off if not impossible.

Then you need a method to determine the speed of a light pulse for example. You need to see the pulse as it starts and ends at a different position and time it to find out the speed. If you say you can see the two spots as they reflect back from the moon, this would then be like seeing two galaxies at the same time and reflecting this back on the speed of light. The two photons are coming from two different sources like the two galaxies.

To do a proper test, you need to send a light pulse to a 45 degree mirror on the moon, travel to another mirror on its surface, then receive it back on earth and time the flight, which will clearly produce the usual speed of light. Sign up to join this community. They can cause burns to the retina. A person cannot turn away or blink fast enough to prevent retinal eye injury from a Class 4 laser. Improperly used laser devices are potentially dangerous.

Effects can range from mild skin burns to irreversible injury to the skin and eye. The biological damage caused by lasers is produced through thermal, acoustical and photochemical processes. Although laser and IPL technology has not been known to cause skin cancer, this does not mean that laser and IPL therapies are without long-term risks. Eye damage from a pocket laser is unlikely, but could be possible under certain conditions.

Many laser pointers are in the range of 1 to 5 milliwatts mW , a subclass of 3 called 3A. A close reading of exposure limits indicate that a 5 mW laser could cause eye damage. Begin typing your search term above and press enter to search.

Press ESC to cancel. Skip to content Home What happens if you point a laser at the moon? Ben Davis June 1, What happens if you point a laser at the moon? How long does it take a laser beam to travel to the moon and back?

Is there a laser reflector on the moon? What stops a laser beam? Will a mirror reflect a laser beam?