And where does the gravitational field come from when a single photon produces a positronium pair?
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The sun can't just disappear in General Relativity, the local conservation of energy-momentum ( ∇μTμν = 0 ) will not allow it. As a consequence the Einstein Field Equations cannot sensibly be used - they would just be inconsistent. Hence, there is no way to know if a gravitational wave would emanate from where the sun was previously located or if the entire metric must change throughout all of space instantly. There is no correct answer, the situation is just fundamentally inconsistent with General Relativity.But we do have instances of small masses evaporating into massless photons, with absolute conservation of energy and momentum, so what happens to the gravitational field of the electron-positron pair?
But/t, I have seen aerobatic biplanes fly just above the ground
perfectly horizontally, with no angle of attack!?
People have different level of tolerance toward different types of annoyance.Which is why we have civil courts, English law is full of "normally" and "reasonable", and it is an offence to deliberately annoy anyone.
French, and many third world countries, get their democracy through revolution.Hence the difference between the legal systems of France and the UK. The French revolutionaries imposed a model secular state, the Brits, as usual, meandered in the course of 1000 years or so towards a compromise vaguely associated with the Church of England and the monarch but ultimately ruled by an elected parliament and an unelected senate, but crucially preserving the celtic ideal of the state serving the citizen, not the other way around.
The general rule of a civilised society is to encourage behaviors that would more likely bring good consequences to the society, and discourage behaviors that would more likely bring bad consequences to the society.That describes uncivilised societies, which have some kind of predetermined objective. Civilisation is about allowing people maximum freedom to do their own thing without upsetting others. Hence the incompatibility between English (it is an offence to...) and European (it is a requirement to...) law.
Humans differ from animals in that humans have free will and choiceNot a scientific statement. The facts are: