About Time-Light

The following explains why I have questions about the methods used to determine distance in space.

Imagine a room that is completely dark.

You are in the room.

You have no idea what shape the room is.

You have no idea how big or small it is. It could be eight metres long or it could be 22 kilometres long. And you have no idea how high the ceiling is.

You don't even know you're in an enclosed room. For all you know you could be in an open space. It's just so dark.

Everything is completely black - except for a number of small lights which you can see.

The lights are of varying sizes, brightness, colours, and causes.

You don't know this, but some are fluorescent. Others are incandessant. Still others are LED. All different colours and sizes. And still others are candle-lights. And some are actually reflections rather than sources of light.

And their sources are at varying distances from you - some of them are even moving, perhaps undetectably, either away from you, or towards you, or in varying other patterns.

In fact you yourself are standing on a moving platform inside the room - but your movement is undetectable to you: so you don't know which direction you're moving relative to which lights, and how fast. 

Different parts of the room even have varying atmospheres and temperatures caused by a smoke machine here, dry ice there, and dust over there - and still other particles elsewhere. All of this affects the lights between their sources and when it reaches your eyes. It affects their appearance of brightness, colour, size and motion and obscures the nature of their original source.

Other lights arrive at your eye unobstructed. Some lights arrive at your eye sometimes obstructed and other moments unobstructed.

But you are not told any of this. All you see is lights. You are not even told whether all the lights were turned on at the same time or at varying times.

Without all that other information, it isn't possible for you to determine how long ago each of the lights which you are seeing began their journeys to your eye. 

You come up with some experiments to try to answer the question. Some of the experiments seem to tell you how far away some of the light-sources are - especially those lights which happen to be connected to or close to your own moving platform. But for most of the tiny lights, the results yielded by the experiments may or may not be reliable because of the unknowable assumptions the experiments relied on.

On those lights which the experiments don't work for, you try different experiments, which yield answers that vary greatly - and they all relied on certain assumptions which you admit you don't have enough information to be able to prove.

Others in the dark-room are each trying to answer the same questions. Due to the lack of information, each person conducts experiments designed to test ideas which exist in his mind - ideas which are based more on preconceptions he had about the dark-room before being brought into the dark-room rather than based on anything proveable, observable, measurable, and falsifiable in the dark-room itself - without relying on major assumptions. Hypotheses therefore polarise - yet nothing much can be concluded yet about how far away each of the tiny lights are and how long they've each been transmitting light.

And so it seems to me to be with measuring time and distance of light not sourced from near space.