geordief

No but I have seen the Midwich Cuckoos

But does my "equation" show how people think they will get the "why" by following through (futilely) all the "hows" ? I only meant it light heartedly.

Does "why" ="how"^∞ ?

Thanks . That makes sense to me now.

I looks like that . I seem to be getting a fixation on massless particles. Are they especially relevant in the context of wormholes? I wonder how they interact with massive objects if they are not massive themselves. EDIT: i have just realized that photons are also massless . So neutrinos can be treated more or less the same way as photons? They are not as exotic as I thought they were and don't just naturally "cut across" spacetime contours as I was imagining

Why do they hit the singularity (no one can say the singularity actually exists can they? ) if they are not affected by gravity. Why don't they just pass through? Do they interact with matter even though they have no mass themselves?

If the universe is "folded in on itself" naturally can the neutrino pass from one region of space to another cutting across the contour lines ? So if there was any way to encode information into a neutrino it would in theory allow for instantaneous(ish) transfer of information....between regions that would be otherwise far distant if one had to follow the geodesics in the normal way with massive particles. The practicalities of that do occur to me EDIT: when we detect the odd neutrino do we have any idea what part of the cosmos they emanated from?

Do massless particles follow the geodesics in spacetime? What happens to them when they meet a black hole? Can they be used in theory to carry information in a way not limited by the curvature of space?

So (repeating myself) we have 3 small massive bodies and ,if we factor out all the gravitational influences of the rest of the universe (impractical obviously - but in theory) any communication ** between them will take place in a space /spacetime that is curved ? Will that curvature be greater the closer they are to each other? **acceptable terminology?

Sorry , Disregard my earlier post (#291 and possibly the reference to you in post#293) I misread your reply. So the 3 bodies ,regardless of the environment (the universe as a whole) create their own local curvature simply because they have mass? And a "straight line" for the purposes of "communication" between these 3 massive bodies is not what is commonly accepted as straight but a geodesic even in this primitive set up ?

I don't know. Can we have an unrealistic thought experiment? Can I (unrealistically) posit that one or all of the bodies are the observers? As Strange said the rest of the universe would define curvature on the 3 bodies ,I have tried to remove that context and ask if we can talk about the relationship between the 3 bodies per se . I suppose once we have 3 we could number up to any number and we end up with our own (imagined) universe. I thought in Relativity the observer didn't need to be an intelligent person ** necessarily ,just a point of reference. I hope some of this made sense **"intelligent observer" ,that is . I wasn't trying to be that flippant

So we can't disregard the rest of the universe?

Here is a thought experiment . We have 3 bodies far removed from the gravitational influence of any other bodies. We join the centres of masses of each of the three with a line that is the shortest distance. Would those 3 lines define a flat plane or a curved one? My guess is it would be curved...

Well I am glad I seem to be understanding the basics of manifolds in Relativity now.

Should there be a different term to describe "intrinsic curvature" if the only similarity to what one might think of as normal curvature seems only to confuse? It seems to be related to the way distances (however they are defined ) change gradually in a smooth (I forget the precise meaning of "smooth" ) manifold. Would it be reasonable to say that any real object in nature that can be modeled by a manifold is in fact always intrinsically curved to some extent and only mathematical manifolds can be absolutely flat? I understand that the observable universe is supposed to be "flat" on the macro level...

Does that represent a practical difficulty? Don't the measurements from Juno take into account the gravitational well?

If you have 2 observers ,one of whom is in a gravitational well and the other not is it correct to say that the observer in the gravitational well will see the other observer "speeded up"? An vice versa (in a different way from in special relativity where both observers see the other as "slowed down" ) Going down a gravitational well in that case (if I was right) reminds me a bit of "going into hibernation". I wonder if a probe was sent to the surface of Jupiter whether any noticeable such effects might occur (not that I understand Jupiter is very dense,less than 3 times that of the Earth I think.) I don't think the speed of light changes in a gravitational well,dies it?

C'est magnifique ,mais ce n'est pas la .......... Science You know I think it is a bit back to front. First we understand how things work and then we play around with how we describe them (there can be all sorts of ways I would guess) If you look for analogies and try to make the world "fit them" then that is to expect the world to be like that "because we say so".

Space and Time Real Estate. I am sure you might get a few nibblers. Haven't people sold plots of land on the Moon already? https://www.moonestates.com/ http://www.scambusters.org/landonthemoon.html

Assuming there is a gravitational field does this distance you described mean a spacio-temporal distance or (since you are here describing the particles without a direct reference to their place in time) is it ,on this occasion just the spacial distance you explicitly meant? If I have understood GR correctly ,it is my understanding that the spacio-temporal distant does not change but I am not quite sure if this unchangeability of "distance" within the manifold applies to a curved spactime as well as it does to a flat spacetime. Also not sure about by use of "spacio" from a simple language point of view

Certain curved manifolds ? Does that mean different classes of manifolds or just one class of manifold with differing properties? My understanding was that the manifold that modeled spacetime was that with the parameters (correct terminology?) of 3 spatial and one temporal(sign reversed ) components -a hyperbolic manifold. Are there are** ways (manifolds) of modeling spacetime ? ** EDIT: are ="other" ,of course .

Subsequent to the detection of gravitational waves which seemed (to me) extraordinary even if ,apparently it was to have been expected would it be correct to say that the detection of Hawking radiation would be something so difficult that we might even suppose with a huge degree of certainty that it may be that scientists will never,ever actually detect them?

I haven't had time to go into the replies yet but do you stand by that description? I am familiar with the "mass curves spacetime and spacetime tells mass how to move" description but this seems different . Is your word "is" to be taken loosely? " Mass and the curvature of spacetime are intimately related" is what you are saying ? Or "mass" and "curvature of spacetime " describe the same thing"?

Did Newtonian physics predict Black Holes? As I am belatedly understanding it was GR that predicted them but what would Newtonian physics have made of the situation ? Would it have envisaged explosions happening eventually as the mass increased ? How would it have viewed the scenario differently? Were Black Holes something that were theorized and discovered only after Newtonian Physics was "out dated" ? Coming back to GR ,might it be ,as I think I may have heard that we are not talking about a build up of matter but a change in spacetime curvature? Is there any theoretical way such a curvature can be reversed? Is that Hawking radiation? The BH will slowly "empty out" ?

I have given you my first and only "like" in over 20 years on the internet. A cumulative "like" like the way a ref hands out red cards after a long series of fouls. I did ask (and Swansont answered) whether these kinds of questions could serve a purpose. I think they can as they provide a framework for the more bread and butter (or croissants and cream) questions but you are right in that any confusion is as bad as sand in the you know where . I know I said wouldn't contribute ,but it was my OP after all and I am accepting the ticking off