danielj

Thank you, as an aside, I find it very difficult to conceptualise ‘massless’. Perhaps because I think of ‘things’, and they have size/volume/mass. In the case of photons, does this mean that all of its properties are confined to c? Or in effect it is c? A perturbation travelling at c?

Thank you all

If I say that the path of that photon passed close by the Sun before I measured it, then the mass of the sun would cause it to take a curved (longer) path, described in Einsteins General theory, thereby causing that bending effect? And if I used Newtonian physics to try and calculate the same path, it would not agree (with General Relativity) because Newtonian physics does not account for mass/gravity causing deformations in space? Also, with the photon being massless (therefore travelling at c in a vacuum) does this mean that a particle with mass would be affected more or is the curvature of Spacetime the only factor?

Thank you. Ive another question for Studiot, arising from my readings. I went outside in the evening to take a look at the Stars. When those photons that hit my retina arrive there, they have propagated through space, but in what form have they travelled? Were they emitted as three dimensional waves (spherical waves?) and then I have collapsed that wave into a single photon by observing (or measuring?) it? Or am I getting my Classical and Quantum effects mixed up? Also, if I see a distorted star, is that because I’m not viewing the same photon, but one (some?) that have interacted with the earth atmosphere and been absorbed and re-emitted on a slightly different trajectory? thank you

Hmmm..that’s got me thinking 🤔 Could someone (who has a lot of time on their hands) not re-write the Bible, but using the correct Scientific terms? for example “And God said, let there be photons”, and there were photons. But then God realised he needed some electrons to go with them, so He said “ let there be photons and electrons”. That didn’t work either so God said “let there be photons and electrons and protons and neutrons” and that seemed to do the trick, more or less. And the Word was “Nothingness”, which later that week, He changed to “Void”, then later still He changed to “Vacuum” as He wasn’t really sure where this was going and it was all getting very,very complicated, very, very quickly. Word. I’m going to hell aren’t I?

I agree. But personally I found plenty of food for thought. There were parts of the book that made me consider what existence could perhaps appear like from the perspective of other animals. If you accept that we are very similar biologically (in complexity and functionality) to many other animals, then the book led me to recognise that I am in a bubble of experience of my own (brain’s) making. I cannot escape it. I see the universe as I see it and however hard I try, that is my lens. I may as well be a Whale, potentially I could be thinking the same thing (in Whale language obvs🙄) If nothing else, the book gave me a different perspective on my place in the universe (or lack of it ). Somewhere in the brain, something tells (some of) us we are ‘special’ in nature, a natural evolutionary arrogance if you like. Human Centric. Or perhaps we learnt that from previous human behaviours over the last few thousand years. It’s been a fair while since Darwin or whoever worked out that’s not true, and maybe that is a feature of the human brain too (might need to think that one through). I think what I am trying to say is that we shouldn’t underestimate and should understand our cognitive limitations on what it is possible for us to know, given that we can only view the universe through our very narrow field lens. Mr Lanza’s book made me realise that. I’m not suggesting that you lot don’t already know that, just an eye opener for me.

‘Biocentrism’ by Robert Lanza, MD has some thought provoking things to say on this subject. Was also a well written, researched (as far as I could tell) and an enjoyable read, in my own opinion. His thoughts centre on the theory that all living things are conscious and that from that consciousness, the Cosmos arises. Immortality is invoked somewhere, I recall…. It didn’t convince me, but I still enjoyed the book.

Thank you, thats all very helpful. Would you mind expanding the above statement please? Cosmological Principle? at sufficiently large scales, the universe appears as homogeneous and isotropic Copied from Mordreds thread ‘Cosmological Principle’ there I go with a guess again 🫣

My take away from this is that I am lacking logical thinking skills, when it comes to physics. In that, I can’t make assumptions and expect to get the right answer. Understanding the question is more important than the answer I think. thank you

I see, yes. Thank you. I get caught in the details, not always helpful to me.

Thank you, much appreciated I’m just trying visualise some of the mechanics of this, so would it also be true to say that if I (tried) to take a ‘snap-shot’ measurement, with any combination of inertial/accelerating reference frames that in reality there is no way to take a snap-shot, as what was the time frame of the snap shot (by that phrase I mean a static measurement) and no matter how small the time frame, change will have occurred in one or more dimensions? The questions should get less stupid as I progress, but I can’t promise So they were above you if you used the ground as your reference frame, but not if you used the rotor itself? Your brain used the ground? reading this back I see there being potentially many different frames of reference, equally valid?

Would you mind just expanding that a little for me please? I can see that human perception skews reality somewhat, but I can’t work out that bit for myself. thank you

The relativistic effects of being in an accelerated frame of reference can be derived from special relativity. That is, acceleration doesn't produce relativistic effects separate from that of velocity. However, the relativistic effects of an accelerated frame of reference are nevertheless different from that of relative velocity. Specifically, clocks that are below you are slower, and clocks that are above you are faster, with the amount by which the clocks are slower or faster depending on the distance of the clock from your location in your accelerated frame of reference. Thank you , that is a very useful explanation that I can (just) grasp.

It does. Sorry, I didn’t mean it the way it came across. Obviously there would be an effect of time slowing at an accelerated rate from the (let’s say) constant acceleration. It was more the ‘are they equivalent’. I guess they are from your other answers and from the answer that time would slow for both observers from the others point of view. thank you

Could you clarify for me please: the statement ‘(the faster you go, the more slowly you age)’, quoted from World Treasury, T.Ferris. If it were me travelling faster ( and faster) would time be passing more slowly for me? (Would I feel it) or only from the viewpoint of some one else not in the same location taking measurements? Or, if I were taking measurements of them, would I record time speeding up for them. Do you see what I’m getting at? also, what would the difference be between me in an accelerating rocket going away from a planet, and measuring from the rocket, and standing on the planet and measuring the rocket receding into the distance? Are they equivalent? Simple as you can please thank you Or in other words, does the fact that the rocket is accelerating have a bearing on the measurement (the dilation effect)? I’m rambling a bit , I know but just trying to think it through. One question leads to another! does the orbiting planet also use energy (as the rocket does to accelerate) to stay in orbit, rather than just fly off in a straight line into space?