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There is an inherent uncertainty in the precision with which complementary variables (e.g. position & momentum) can be known, regardless of external influence from observation, due to the wave-like nature of quantum objects.
With an extremely fast shutter speed and very fine frequency (of light) resolution you could take a picture of an object (showing where it is) and its velocity relative to you (looking at the Doppler shift of the lift returned to you) without detecting any blur. This is THE way traffic police measure speed (they look at Doppler shift of microwaves/radio waves, but it's the same idea). The uncertainty principle arises from the fact that there is no way to "observe" something without interacting with it. And that interaction necessarily changes the trajectory/position/energy etc. of whatever is being observed.I will take this opportunity to address a common misconception about observation. Observation and interaction are exactly the same thing. There is no requirement for a human or consciousness or anything of that nature for observation--just interaction of the particle/wave of interest with another particle, wave field etc. For instance, the uncertainty principle become very important with very, very short laser pulses (duration/frequency uncertainty arises the same way as the position/momentum uncertainty). The shorter the laser pulse, the more uncertainty there is in the frequency (color) of light coming out, so much so that pulses on the order of femtoseconds can be thought of as "white light." In this way a "red" laser with not enough energy to excite an electron in a molecule (say it requires "green" light) can have a nonzero chance of causing that excitation if the photon only has a very, very short time in which it could interact with the molecule. No human observation is required here, it is the molecule that "observes" the light by interacting with it.For macroscopic objects there is no apparent paradox because the degree of uncertainty is typically several orders of magnitude less than the size and speed of the object itself.
Measurment of a photon takes time, doesnt it? Neasuring a photon is measuring how the EM field changes with time.Does that mean when looking at the dopler shifted photon we are stil looking at a tine t0 and t1 abd deducing the frequency from that time interval? And from that interval, ultimetly, the speed of the object?
It's worth noting that the 'Observer Effect' described above by chiralSPO is not the same as quantum uncertainty (Heisenberg Uncertainty Principle). There is an inherent uncertainty in the precision with which complementary variables (e.g. position & momentum) can be known, regardless of external influence from observation, due to the wave-like nature of quantum objects. This is the same quantum uncertainty that gives rise to zero point energy, the lowest energy a quantum system can have (it's 'ground state'), which is not zero, so no quantum object can be completely motionless.