This discussion centers on the implications of observing objects approaching the speed of light, specifically addressing phenomena such as Terrell rotation and the effects of light's finite speed on spatial observations. Participants highlight that particles in accelerators, like those at CERN, routinely reach speeds close to light, with discussions on the energy requirements for accelerating a nano-camera to 10% of light speed. The conversation also emphasizes the importance of understanding relativistic effects and recommends specific literature for further study, including Taylor and Wheeler's "Spacetime Physics" and Morin's "Special Relativity for the Enthusiastic Beginner."
PREREQUISITESPhysicists, students of relativity, engineers working with particle accelerators, and anyone interested in the effects of high-speed motion on observation and measurement.
It is true that the finite speed of light has effects on direct observations - Terrell rotation is one. But that does not stop objects moving close to the speed of light with respect to another object. You are doing it now, for instance, with respect to particles in an accelerator.Atlan0001 said:If one observes some object nearing the speed of light, the spatial observation is far behind the times.
It depends how quickly the object is accelerated and also on the shape and direction of the path. An object could be accelerated towards you and you might measure its speed as it passes a short distance away. Or, an object could be accelerated in a circular path and you could measure how quickly it completes each circle.Atlan0001 said:If one observes some object nearing the speed of light, the spatial observation is far behind the times. The object is now (time) elsewhere in space . . . all the way to distantly far elsewhere from the observed placement in space.
tl:drPeroK said:It depends how quickly the object is accelerated and also on the shape and direction of the path. An object could be accelerated towards you and you might measure its speed as it passes a short distance away. Or, an object could be accelerated in a circular path and you could measure how quickly it completes each circle.
In any case, particles in an accelerator are routinely accelerated to near light speeds:
https://en.wikipedia.org/wiki/Particle_accelerator
A high energy muon just fell from the sky at 99.9% of the speed of light and face-planted in the ground three feet to my left. My experience of it is a mere 10 nanoseconds old.Atlan0001 said:If one observes some object nearing the speed of light, the spatial observation is far behind the times. The object is now (time) elsewhere in space . . . all the way to distantly far elsewhere from the observed placement in space.
You would see rather odd things. If you try to photograph macroscopic objects moving at respectable fractions of the speed of light the variable travel time of light to your camera from different parts of the object becomes significant. Roughly speaking, you see the object rotated, not length contracted.OmCheeto said:I'm interested in seeing actual results.
Power depends on how long it takes to accelerate the camera to .9c. But energy required we can calculate: The ##\gamma## factor at .9c is equal to two and change, the energy needed is ##(\gamma-1)mc^2##, so maybe one back-of-the-envelope gigajoule.OmCheeto said:Anyone know a quick back of the napkin number of the power involved with a moon diameter particle accelerator which accelerates a nano-camera to 10% of light speed? I'm interested in seeing actual results.
guesstimation of mass of nano-camera: 6e-8 kg (they said it was about the size of a grain of salt)
I usually recommend Taylor and Wheeler's Spacetime Physics, although others prefer Morin's Special Relativity for the Enthusiastic Beginner. The former can be found free on Taylor's website, the latter costs a few quid although the first chapter is free for download.pinball1970 said:A few misconceptions going on and you could use a solid beginners reference.
@Ibix
https://www.eftaylor.com/spacetimephysics/Ibix said:I usually recommend Taylor and Wheeler's Spacetime Physics, although others prefer Morin's Special Relativity for the Enthusiastic Beginner. The former can be found free on Taylor's website,
No. The object could be passing through your current location as it "approaches the speed of light". There is no requirement that it be at some distant location at that time. In fact, if you think so then post an observer at that distant location and have him record what he observes as the object passes.Atlan0001 said:If one observes some object nearing the speed of light, the spatial observation is far behind the times. The object is now (time) elsewhere in space . . . all the way to distantly far elsewhere from the observed placement in space.