I have a question I can not find explained adequately enough that I finally understand the answer.

I was wondering, If the light we see here on earth emanating from space is sometimes millions of years old, how can we see real time events like super novas exploding, or other such events that we measure?

Are those events actually a time lapse photo from the past?

If so, does our entire knowledge base come from events that happened many years ago?

Also, if this is true then would our knowledge of the universe be knowledge of how it was millions of years ago and not how it actually is now?

Like if the images we got back from the rovers on mars took millions of years to get back to earth, we would not know how it is now, we would see images of how it was when it first landed. Similarly if the light we see and measure the universe by is so old, then might the stars we observe not even exist anymore?

I would venture to say, basing my argument off my assumptions, that the universe may then not be expanding anymore. It may in fact be dissolved already or be in a state of "crunch" where somehow gravitational forces have begun to crush it all together again.

How long would our perception of any event in the universe take for us to observe it.

Like if mars was destroyed by an asteroid, we would have some lag time until we received the images here on earth. Similarly, how long would it take for the measurable observations to change for us if the universe stopped expanding?


Thanks in advance.

EDIT:
Also how do gravitational distortions of time factor in?

EDIT TO ADD:
I understand we measure certain wave frequencies of light to see how it progresses through the universe, BUT wouldn't that light, even from what ever particular part of the spectrum be subject to the same time lapse and distortion as the full spectrum?

Cool question, light travels at 186,000 miles per second, if the sun just "shut down" we would not know it happened for approx 8 minutes. Any event observable from space happened long ago and is approxamated by it's distance from earth in light years, this is the distance light travels in 1 year. yes, we are seeing the long ago past in our skies. If a distant star went supernova today, it could take millions of years for earth to have a view of the event. If our universe is in a state of collapse, and the rate of collapse is at the speed of light, not FTL, (faster than light) we have not a clue at this point of reference. There would be a distant early warning.

it would be interesting though if everything we experience was just a time lapse of something that already happened, it could explain deja vu?

Well that makes me think, when we observe other galaxies can we be sure that we are looking at something that's still there? or just the light of what used to be there just now reaching where we are now. There would probably have to be a black hole the size of that which we can not describe at the center of the universe

With what little we really know of our universe, and it is very little, even that is based in theory, sheer theory. common theories are that gravity does not effect time, but does effect or distort light. a mere second after the big bang (theory) objects and matter moved outward at a rate of speed, and if without resistance to movement or gravity, are still traveling at that rate even now. Our universe is amazing in all aspects, with wonders abound, anything you can dream could, theoretically be possible. on another post I said" to me, our universe is a small box, in a huge warehouse, in a massive complex, in a big city, in a Texas size state, in a large country, on an gigantic planet, in a really big solar system, in a massive galaxy, in a big universe, inside a small box, in huge warehouse"...I can see no start or end to time and space, even if it is round, wouldnt it be like a marble in a box, next to another, and another. If a viewable event were happening, we should be able to see it long before it reached us, like distant storm clouds approaching, but there are possibly unseeable forces that may effect objects, like radiation, you cant tell it is there without instuments until you see its effects. So, so many possibilities, never stop searching....