julius2

Good question. It seems that our current time / universe seems to be explained perfectly well by 3 spatial coordinates and 1 time coordinate. So why the need to add another time coordinate? Having 2 time coordinates leads to 2T physics. It seems the research has already been done with such a scenario with advantages / disadvantages of the theory. And it is even more complicated / problematic with a 3T model (apparently). Put simply, space time (Einstein Field Equations) help explain gravity at the least.

It is interesting to investigate the concept of energy. But if we could just go back to the concept of spacetime for a bit. If there is a mug sitting on top of a table (stationery) then it's footprint in spacetime might look something like: (0, 0, 0, 5). at t=5s (0, 0, 0, 10) at t=10s (0, 0, 0, 15) at t=15s etc. That is, it's "world line" would be vertical as the mug passes through time. If the mug were to move through space it's "world line" would be slightly diagonal as time slows down. Is it possible to have a spacetime which is more like (x, y, z, t, t1, t2)? Where t1 is time from a previous universe and t2 is time from another previous universe. So in other words adding more parameters to spacetime? Assuming that previous universes did exist.

Thanks for highlighting the point. I have read that pure energy can exist. For example electric and magnetic fields carry energy without requiring mass.

The question for the universe, is where did all the matter come from? I know this is one of the great mysteries of science. If the universe is a reconstitution of previous time(s), the question still remains, where did all the matter come from , from those previous time(s). So still a mystery. E = m c 2. Indicates the interchangeability between matter and energy. So really would we just have to investigate why energy exists? What makes energy come in to existence? (From physics, electricity comes from interaction between kinetic energy and a magnet)

Sorry, IS THE CURRENT UNIVERSE A RECONSTITUTION? If this is the case, more research needs to go into how things reconstitute. Experiment: Study how things reconstitute. Then devise experiments that seek to "pull apart" objects. (in time) If this holds true, then this would be empirical evidence of a reconstituted universe. Caveat: This is the danger of going from what we do know and can be readily measured. Better is to ASSERT a theory and then look for evidence that fits the theory. Not enough assertion is being done. If the universe is a reconstitution then we can SKIP the big bang idea.

I am not sure if the youtube and science document are meant to confirm that you are able to get some kind of reversibility?? I would not expect the 3 blobs to be re-constituted after being so largely smeared. It is interesting that things can be re-constituted. Is the current universe a reconsitution?

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?

True. It would not be a simple extrapolation. First, we would need to know what sort of environment we are dealing with. For a simple case, the other planet could just be a mining settlement. Earth using it to mine for precious metals / resources such as magnesium, iron ore, oil. But would this just prolong our existence on earth? What is the end goal? If we as a planetary species are imaging a Star Wars like scenario, exchemist made a good point. On all the planets (desert planet, ice planet, Yoda planet etc), humans were freely able to breath the atmosphere. With this reality check, Star Wars is not believable at all. Yes, I know it is "just" a movie.

Why? I guess we would need a planetary vote on it.... But everything we have developed could be "duplicated" on the new planet. The economies of scale would be enormous. For instance, mining. How long has it taken humanity to develop all the science (periodic table), mining methods. We had to have the renaissance before we had the industrial revolution, which allowed us to make the machinery to undertake deep sea drilling etc. Our financial systems could be extended. Not only would we have an earth banking system which we have now, but an interplanetary banking system - depending on what resources are available on the new planet etc.

I guess following this thread, brings to light that is not such a straight forward question. The nature of such an earth-like planet would have a great effect on what we as humans of this world would do with it. For instance, we would not want to contaminate the new planet with stuff from earth, or likewise we would not want to be contaminated by anything living from it's environment. I guess I didn't think this far ahead. I guess it would be "rewarding" for this world to find another planet capable of being developed. But it would not be half as much fun if we were forced to wear space-suits everywhere on the new planet. So I guess we should appreciate the "luxury" of being so well suited to our existing planet.

Contamination would be an important consideration. Who knows what kind of bacteria would exist on the planet. It would depend what kind of vegetation exists on the planet. If the environment was found to be harmful would we try to invent vaccines?