Stars in our Galaxy are relatively close, so those we can see as wee look inwards towards the centre (as well as the few we can see when we look outwards that are very local to us) are between 5 LY to 100,000 Light years away. So the furthest we can see into history in our own galaxy is about 100,000 years.

This is another factor in why some objects may not be visible, because their light intensity might not reach as far, so only a small amount of light reaches us, or something might be in the way, that light can’t penetrate.

This is why lasers are more intense, because the photons are more focused so they don’t disperse so easilly.

Hence my earlier comment, its like a a byte of computer data, trying to comprehend the VIC-20 that it exists inside of.

One single brain cannot compute the whole picture. But Network them!!!!

we can see our own Galaxy, but only from inside it. Its like asking why can’t you see the outsie of your house when you are sittying in the living room. If you mount a camera across the street, you will be able too.

We cannot look back at earlier light from our own galaxy, unless we are far enough away from it to observe the light that has already been emitted from it.

As we are local to our own galaxy we can only see light from our nearby stars. When you look up at the night sky (if you travel far enough into the countryside, way from the lights). You will indeed see our galaxy, as a vast and densely populated field of stars, in a thick band. This is the Milky way looking towards the centre of the Galaxy.

City lights, street lights, and the moon all interfere with the visibility of it under normal suburban circumstances, which is why you only see the brightest stars and planets on most given nights. This is known as “Glare” in true darkness of night, out in the sticks, you can see the splendour of the milky way. It is why most telescope observatories, are miles away from anywhere.

It is indeed entirely possible that what we see may not exist. In fact the further away it is, the more likely that it doesn’t (or at the very leat it would look very different to how we see it now).

It is also valid, that there is a limit to what we can see due to the expansion of the universe, that object may exist that we will never see, because they are too far away for the light to ever reach us.

It is for this reason, that relativity is so important. It teaches us that “relatity itself is relative, and really there is no such thing as a true definable reality”, as it is different for everyone and everything depending on the circumstances, and the relation of one thing, to everything else.

Consider this, when you empty the bath or flush the toilet, most people are aware that in the the northen hemisphere the water spins down the drain in the opposite direction to the southern hemisphere. This is called teh coriolis effect. It demonstrates however, the illusion of reality. It is actually spinning in the same direction. The relative position of the observer changes, in the northern hemisphere the observer is looking at it from on “side” and in teh southern, the observer from the other”. Its like one person standing in front of a transparent clock, and the other standing behind it.

Clockwise to observer 1, is anti-clockwise to observer 2. This demonstrates the illusion of reality. Realising such things, helps break down an unlearn what we have learned helping us understand “Relativity” and to see the universe in a relative way. However this too is just another interpretation of relativity. So relativity must also be relative.

This very comment is relative, as its based on the ay I see things, and currently interpret them.

Once an object has emitted light, the light that has already been emitted will keep travelling until is absorbed.

If I turn on a light in my house, it continues to emitt light in all directions while it is turned on. If I turn it off it stops emitting light, but light that has already been emitted is still “airborne”. Practically speaking the distance between you and the light is so close that it seems near instantaneous”. In reality it is like waching a supersonic jet plane fly past, you see it fly past, and then you hear it. Same with lightning, yo see it, then you hear the thunder.

With light, it is similar, if the sun exploded now, right this second, you wouldn’t know about it for 8 minutes. The reason is Light already emitted from the sun 8 minutes ago, is only just reaching us now. In realtime the sun is 8 minutes in the future from our “relative” perspective. Even though the sun dies, teh light already emitted is still travelling.

A simple example is, you just left the city (sun) in your car (light). You have a 10 kms to travel to get to me (earth). Then 2 minutes into your journey, the city gets destroyed, but you don’t. Some 6 minutes later, you rock up and say how lovely it is in the city, nice and calm, unaware until another car arrives 2 minutes after you filled with screaming people fleeing in panic.

8-)

Now let me get this straight., The universe today is bigger than it was yesterday (or even further back). So looking at the same fixed point… say a Galaxy 13.7 billion light years way), while the light is travelling from the fixed point to us, the universe is also expanding, so it might actually take longer to reach us as it is running on a tread mill at a fixed velicity but the treadmill is getting faster, which means “relatively speaking” light gets slower as it travels further even though it travels at the same speed (of light). I can see how this would effect both the actual size, and observable size of the universe, and why it has time to expand beyond the range of light “when considered from the relative perspective of light”.

Could this mean that the escape velocity of the universe is not possible to be achieved, because the universe will always be larger than the maximum velocity of light so you could never reach the edge to escape (unless the universe stops expanding or begins to crunch).

Then there is the other question, if you could reach the escape velocity of the universe, escape to where? What happens if you cross the event horizon of the universe.

I believe I’m beginning to understand the concept of the “event horizon’ and “Time dilation” a little better. The edge of the universe is simply an event horizon, as we get ever further away from the ground zero “event” of the big bang, so the edge of the universe gets further away from us. It would be similar to being caught in the event horizon of a black hole, you can never achieve escape velocity, not even if you are light, because of “Time Dilation”.

Physically the universe could exist as a near flat plane, but surely only if there is something at the center to cause an axis to be created (eg a nucleus of immense gravitational force (enough to eventually pull black holes back in, and eventually crunch teh universe). This would be acceptable based on what we know of Planets revolve around suns, Suns revolve arround Galactic Centres, so it could be feasible that Galaxies are all revolving around the central core of the universe, which would cause the universe to exist as a “plane” with some level of depth or thickness, but essentially a flat disc like a galaxy)

It would aslo mean that all the visible universe (including us) as well as the non visible universe of stars and galaxies outside our perception (all Matter and/ or dark matter) would all be on that outer event horizon (as it is all on the surface of the ever expanding surface or “crust” (spherical balloon – that inflates from the centre, or expands because of vacuuum, whichever way you want top look at it).

Everything back from the crust to ground zero would be empty space-time, even devoid of light as all the light has long since travelled past the source, but has not yet caught up or overtaken us as we can always stay ahead of it due to the inflation of the universe. The things we see as observable now are mostly due to the light, that travels with us, that has travelled with us since the dawn of time because it can reach us from its emission point.

Only took 2 years to reply, not a bad effort!, I’m losing focus so I’ll stop now.

Total FAIL!!!!