bloodhound Posted September 14, 2004 Share Posted September 14, 2004 Imagine a laser beam shining at the moon. if you move the beam. with enough angular velocity. due to the fact the the points speed at distance r is spped = ang. vel times r. wont that point of light be moving faster than light on the mmooons surface. And if that is true, would we see a discrete set of points like firing a machine gun while moving fast enough. Link to comment Share on other sites More sharing options...
[Tycho?] Posted September 14, 2004 Share Posted September 14, 2004 When you talk about discreet points, are you talking about individual photons? Because those would be difficult to see. But yeah, sure this seems true. Link to comment Share on other sites More sharing options...
bloodhound Posted September 14, 2004 Author Share Posted September 14, 2004 was the set of points continuous in the first place? was taking light as a wave. it should be. but what happends once that point where the light strikes the moons surface starts moving faster and faster Link to comment Share on other sites More sharing options...
[Tycho?] Posted September 14, 2004 Share Posted September 14, 2004 I'm not really sure what you are looking for here. Link to comment Share on other sites More sharing options...
bloodhound Posted September 14, 2004 Author Share Posted September 14, 2004 just making random posts Link to comment Share on other sites More sharing options...
Thales Posted September 15, 2004 Share Posted September 15, 2004 There is no such thing as rigidity in special relativity. As you move the point across the sky the photon beam will bend slightly as each successive photon will be ejected on a different trajectory. The same thing happens with solid objects. If you have a really long pole, for instance, and you try to use it to send messages faster than light by pushing at one end the pressure wave, placed on particles in the atomic lattice, is restriced to the speed of sound in the material. This is a similar concept to what I think your trying to get at here. Link to comment Share on other sites More sharing options...
swansont Posted September 15, 2004 Share Posted September 15, 2004 Imagine a laser beam shining at the moon. if you move the beam. with enough angular velocity. due to the fact the the points speed at distance r is spped = ang. vel times r. wont that point of light be moving faster than light on the mmooons surface. And if that is true, would we see a discrete set of points like firing a machine gun while moving fast enough. Yest, the point will move faster than c. No, it doesn't necessarily mean we see a discrete set of points - it depends on the photon flux. You could see this effect on a much smaller scale if the photons were emitted slowly (rate-wise) enough. [pre-emptive]Oh, and this doesn't violate relativity, either.[/pre-emptive] Link to comment Share on other sites More sharing options...
RICHARDBATTY Posted September 15, 2004 Share Posted September 15, 2004 I get what you mean but the light isn't realy moving sideways. Its just like shooting a machine gun. You fire bullets in rapid sucssesion while changing the angle of the gun. Each bullet reaches the moon at the point that its trajectory took it but it does not move side ways. You may have a good particle/ wave experiment though. If you moved the beam fast enough you would get seperate photon impact sites with particles. Link to comment Share on other sites More sharing options...
daedelis Posted October 2, 2004 Share Posted October 2, 2004 Yup. Not in violation much like firing a single photon in opposite directions causes their motion relative to one another to equal 2c. Link to comment Share on other sites More sharing options...
Aeschylus Posted October 2, 2004 Share Posted October 2, 2004 Yup. Not in violation much like firing a single photon in opposite directions causes their motion relative to one another to equal 2c. Not strictly true as the two photons do not have relative speeds as they do not have refrence frmaes. Taking the limit of the compostion of velcoties law you actually get an answer of c. Link to comment Share on other sites More sharing options...
philbo1965uk Posted October 9, 2004 Share Posted October 9, 2004 edited out im wrong. Link to comment Share on other sites More sharing options...
CPL.Luke Posted October 24, 2004 Share Posted October 24, 2004 you would get lots of points on the moon (depending at what rate the photons are emmited. I think it would work much better if you used a laser that emitted one photon at a time (if this were possible) then assuming you moved the laser fast enough and looked at the moon you would see little points. but they would be scattered across the moon and not in a single line. this is because the photons impact point is decided by a probability wave (two slit experiment) however I am not very familiar with the physics of this Link to comment Share on other sites More sharing options...
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