"Either dead or not dead, existed or did not,
universe would end for some observers and not for others"
If you believe in the Big Bang theory, you must agree that we and everything in the universe were closer together in the past. The sequence is like big bang ( beginning)- now- and then big crunch (the end). From nothing to nothing. It sounds very simple, but in astronomy and cosmology, which categorized as branch of science, everything has to be proven. Oftentimes, mathematically. And it's getting more challenging because the objects you observe are far far away, you can only see them through a lens of telescope. Oftentimes too, the object comes from the past. Million years of the past. So, it's like an advanced History with lights, nebulae, or microwave radiation background as fossils to examine. And it requires scientists from generation to generation to pass the work. From Galileo to Albert Einstein. From Roger Penrose to Stephen Hawking.
To be accepted, theory should explain current condition consistently and also predict the future. For example, once Einstein made a calculation about his theory of relativity- that gravity is a bent of space-time caused by mass, so when light passes near a massive thing in the universe (like our sun, of course) it will be bent. Several years later by observation, astronomer found it's true. There was a solar eclipse so it was possible to see that light from a faraway star bent when it passed near our sun.
Predicting the future is always a fun thing to do. Is the Big Crunch theory true in explaining the fate of universe in the future? Or are there any other theory?
Scientists have been in attempt to understand and figure out the fate of the universe. Will it be there always, will there be an end? If ends, will it be in a one big explosion or in more slowly pace, star dies one by one peacefully. We still try to understand too whether universe is open or close/ finite of infinite? What is the shape of the universe? If we fly far enough to one direction, will we see the start line again from the opposite direction? Or we'll just fly forever to never ending sea of stars.
Stephen Hawking, in his book, A brief History of Time, mentioned that universe began in one explosion sometime in the past from singularity. Singularity describes one condition that cannot be explained; when physic laws (like time and space itself) don't exist. So there's no point considering it. It's the "nothing". Stephen had this idea when he was attending one course about black holes by Roger Penrose in 1960's.
If black holes can suck everything and disappear in to singularity, considering that universe is expanding now, if we turn back time, so everything is closer and closer and very dense, it'll disappear into a singularity too.
But that's when we don't consider the quantum effect.
It's not a secret that general relativity and quantum mechanics don't mix. That's one of the reason why we haven't found that "Theory of Everything" yet. Because general relativists don't quite like the idea of quantum mechanics, even though it is considered as a very strong branch of physics and make sense mathematically, if not by observation.
The other reason is that in the heart of quantum mechanics, lies the uncertainty principle. Popularized by Werner Heisenberg, it says that you can't measure two parameters in precise number for both. For instance, the more you measure a position of an object, the more you won't get precise measurement of its velocity, and vice versa. You've got to lose one. So there has to be more than one condition of something: there or not there, die or live, jump or not jump. There's no certainty until we do the observation. Nothing is certain until we do the measurement. It's like a present box that contains thing that always changes form; we don't know what's in it until we unwrap it. Â That sounds like a crazy ghost theory if we see in a larger scale, but in quantum scale, you know it's true.
