Hi Ethan,

I have a few physics questions I wondered if you'd consider responding to:

1. Does gravitational attraction constitute 'work' and if so what is the energy exchange? E.G. how can a mass continue attracting other bodies without some sort of fuel or mass exchange? Why does gravity seem to be a free energy/perpetual motion machine?

2. Does the past have any actual existence? Humans seem to conceptualize the past as if it was part of a journey through space so we think of it as somewhere we could potentially revisit - but aside from our memories and the way we build our identity out of these does the past have any actual existence? I know that physical energetic processes could run backwards as well as they run forwards but that's not the same as something having existence in a previous timeframe is it?

3. I don't understand the point being made by the Schrodinger's Cat thought experiment. If I cast a pair of dice under a cup no one knows if the sum of the dice is even or odd until the cup is lifted. Are the dice in a quantum super position then? Why do we need a cat, cyanide gas and radioactive material to illustrate this and what is so special about that? The experiment also refers, I think, to quantum entanglement and the 'fact?' that entangled quantum particles affect each other instantaneously at faster than the speed of light. Is this correct? This seems like a big deal but I don't understand if it is a) correct or b) related to the Cat experiment.

Thanks!