julius2

If you had a puddle of molten steel, perhaps you can "trace" the molecular structures in it to check if it used to be a previous object. It would be difficult. You probably would require a supercomputer to "remodel" the item. Or would it be the task of a future possible quantum computer? In the early universe? Why? Because we see living things around today. In other words was there something "living" in the early universe? If not, did "living" appear at some point afterwards? It has to happen at some point. Like I said, just take a walk in a forest.... Looking at Michio Kaku's book he talks about the universe being fine-tuned. He talks about many "accidents" that put us in a narrow band allowing life to exist. He talks about a number of variables: Epsilon = 0.0007, N = 10 exp 16, Omega (relative density of the universe) etc. How come the universe is so fine tuned? If some of these variables were different by just a fraction life would not exist ?? Realistically speaking modern science has only been around for the past 200 -300 years. A small amount of time compared to the 13.6 billion years life of the universe (calculated). So really, no one knows what was around before.

Using one of the AI query engines, scientists have in fact examined various models where the singularity is avoided (as expected): - Loop Quantum Cosmology - Imaginery Time (Hawking) - time becomes complex avoiding singularity - Mirror Universe (CPT symmetry) - Quantum Tunneling Models Without going in to detail, it looks like the possibility has been examined. In terms of testability, my thoughts are to build a model where there is a something "before the universe" giving rise to new equations. Giving rise to changed "designs" for experiments. (Not a discovery approach.) Remember, we have to account for "living things". If you need empirical evidence, just walk in a forest. I am expecting a model / set of equations that can explain A to Z.

Thanks. I guess what I am thinking if we could solve a lot of science's perplexing problems, by extending the arrow of time backwards. The one thing your statement doesn't accept is "before the universe", but there was "before the universe".....

Thanks for the explanations above. I understand that there is quantum mechanics which deals with the things of very small. And general relativity (dealing with gravity?) to explain things of the cosmos. I take it Newtownian mechanics is kind of in between? I still come back to my first assertion, is that how do we know there was not "something" before the current universe? From my viewpoint, current science has been heavily reliant on a "discovery" method. Going from the Renaissance, through the Industrial Revolution period and 20th century. It is as if the universe exists waiting for us to discover everything. If we postulate that there was "something" before the BB, then we may go to a "SEARCH" position. We search for how we can access previous time etc. Anyway, the world is going towards AI. Perhaps scientists can use AI to do this? (claim / disclaim). Or even to find the "grand unifying theory" that unites quantum mechanics and general relativity. ?????

Still reading over the overview of the Friedmann equations, but first, - a(t) is a kind of "velocity" i.e. rate of movement between two points in spacetime? - the BB singularity, is this a "mathematical" construction, or does it have a physical meaning Is dark energy a way of explaining the expansion rate of the universe, in other words without this phenomenon the equations just won't work? Sorry I didn't do 3rd year uni maths, is a tensor like a matrix? From memory, multiplying 2 matrices together and expanding can reveal several lines of vectors? You don't know of a good article for Einstein's Field Equations?

According to a source, the expansion of the universe is due to space itself stretching... Looking at the First Friedmann equation for explaining the expansion of the universe, the right includes terms: - energy density - curvature of space - dark energy Is the equation some kind of "balance"?

I see. This sounds like spacetime to me. So (if) the universe is made up of spacetime, you can't apply a simple Newtonian mind to it. So the concept of our very existence is weird?

According to research, the universe is expanding. We "know" this from observation. How does this work in practice? Is the universe expanding "in" to something? Or is the universe itself perpetually pushing a "boundary" ?

Valiant attempt. I guess the point of my post is that if we think out galactic trade properly there are all sorts of complications. It is these complications I wanted to discuss. In other words (galactic trade) ain't going to happen. With the world in it's current form anyway. But we have built this world on science and it is not done yet (AI etc). There may yet be a "discovery" to save us.....

Hopefully this "analysis" is thorough enough to be classed as science : Looking at the practicalities of existing / trading in space. Take a standard mode of transportation - a star cruiser (space ship) - in a space environment. Would the star cruiser be owned by a corporation? What would be the cost of such a star cruiser? Where would you buy the star cruiser? You would assume there are a number of suppliers? In an intergalactic star system suppliers may even be spread across multiple planets? Parts I would assume there would be different parts for different makes / models of the star cruiser. Would there be a marketplace for these parts? How would this be run? On a kind of internet? Would there be a "stock exchange" on various planets? Maintenance crew Function - they would maintain the star cruiser engine / pipes / computers / navigation Practicality - how would this crew be fed? What would happen to the waste product? Would it just be dumped in space? Complexities of having a maintenance crew. Presumably some would have families (just like here on Earth). How often would they visit their family? How long are their trips away? Would they be able to communicate with their families? Would there be various interstellar "souvenirs" people could give to their families from their trips away? With multiple habitable planets and feasible space travel possible, everything is 10 fold bigger. The problem is our "space environment". We are stuck with our "environment". Would there be a future time when intergalactic is possible? Or has one existed previously? This would all depend on the mechanics of the Big Bang??

I approach this discussion more about how did male and female come about? In this world we need both male and female for reproduction and furthering the species. It could be animals (lions, tigers etc) or humans. But is this generally a requirement overall? Is it possible that reproduction can occur with non-sex entities? (Not found, but a thought question). Did the first micro-organisms have male / female. If not, how did male / female develop? Does nature find it advantageous to have a male / female setup?

So, if I understand correctly, "7 pm on the corner of 5th Avenue and 24th Street in NYC" is a point in spacetime, that will never happen again?

It is interesting to see others delving with the fundamentals. Having read quite a few posts I still find it hard to grasp the concept of spacetime. Space is pretty obvious with the three dimensions of length, width and height. The concept of time I can "understand". E.g. The "time" it takes from one end of the road to the other. Or the "time" it takes to boil an egg. In other words you "feel" the time and thus have a concept for it. Or for clocks, it is the count of a pendulum swinging back and forth. I have faith in the concept of spacetime since the empirical evidence is consistent with the theory. And it is used to explain gravity (general relativity). Special relativity is consistent with GPS navigation system operation. So all good there. Combining space AND time is confusing however.

Yes, a very big problem. Who would want "floof" in 100 years.... The thing is what makes us think we have a future in the universe? I blame the science of film-making. Maybe not so much in the world today where the movies are a bit "watery". But the 1980s, where we fed ourselves all sorts of science fiction. As a planet we have to be careful we didn't build a "machine" to spark our own death! In other words were the movies one big psychology machine???

I like the innovative thinking. Does this affect spacetime?