>>11112251Observation is a measurement, which implies interaction with the system. You may only gather information from anything external by exchanging something physically. For you to see, light needs to be absorbed in your eyes, exciting molecules within. For a thermometer to measure temperature, it must absorb heat from the environment (or lose it).
In the DS experiment, observation means "placing a sensor at the slits to interact with incoming particles and exchange something to gain information". This interaction disturbs the stability of the incoming particle's superposed state and breaks superposition, relegating it into a definite state.
Quantum superposition is a metastable state of matter and radiation that when in contact with a definite stable state, converts into it, like a false vacuum falls into a more stable, lower energy vacuum, except here the difference between the superposed and definite states isnt one of energy (because it is conserved) but rather one of entropy. When the superposition is broken (wavefunction collapse in Copenhagen, relative frame of reference in MWI), the number of possible arrangements and configurations of matter in the Universe changes. Due to the second law of thermodynamics, entropy causes irreversibility and at a macroscopic scales time seems to pass.
The DS experiment merely demonstrates the difference between the superposed state of matter/energy, and the 'definite', longer lived and apparently more stable state. Its another consequence of time translation symmetry being broken at the Big Bang, and of relativity causing every single event under the speed of light to disagree in measurements depending on their reference frames.
