Is the universe finite?
Albert Einstein already had his doubts: “Twothings are infinite, the universe and the human stupidity, but I am not quite sure about the universe yet.” How can I be sure for the first part of this statement!
Inevitably, one has certain ideas about the universe, of course.But all of this is probably not true. It’s not a ball, it’s not a cube, it’s not a saddle. Why not? Because these are all 3-dimensional objects, they help our imagination, but they are not the whole. We are just 3-dimensional beings. Imagine if there were 2-dimensional beings. They know length and width. They couldn’t imagine a height. She could calculate them, but never imagine them. That’s exactly how it is with us. A multidimensional space goes completely outside our “concepts” (grab, touch).
But first step by step.Before the UR-dingsbums (usually called Big Bang, even though it didn’t bang at all) 13.8 billion years ago, the entire matter and energy of the universe concentrated (stop, I have already put it wrong: also the universe itself, just EVERYTHING, and that was NOTHING) to a single point or was also “from somewhere else”.This often raises the question among laymen, “Where in the universe did this big bang take place”? But this question is based on the misconception of the Big Bang as an explosion inspace, in which matter flew from one point in all directions.But beware: the Big Bang was not a special place in the room where one could erect a monument ” HERE THEUNIVERSUM“, but the origin of our universe.Before, there was NOTHING (or THE ALL).Because where something is NOT spatial, there is no time. Everything was endless… infinitely small!
And then it did as I said … (as I said.it certainly didn’t pop – but we don’t know what, but it did) and our universe was there: space, time and a quarks/ gluon mixture from which everything was built up.This was a tiny room at first, but a room. But how do we measure his tinyness? In any case, this tinyness became larger and larger and expanded. What was, had become more and will continue to grow.
Thus, matter does not expand into an already existing space, but together with space.The Big Bang therefore took place in every place of today’s cosmos.
And this one grew and continues to grow.What we see has a name: the observable universe.
First of all a HUCH!YES, is there also a non-observable universe? Clearly YES! Nothing is faster than the light – we remember “Einstein” – and above it is written, the Big Bang was 13.8 billion years ago, one could also look so far. But this presumption is not entirely correct. This radius has an area of just over 46 billion light-years 鈥?three times as large. this is the particle horizon or observation horizon.As the space expands – we remember – we see much further we see as much as 46 billion light-years.
I had already described this with space and its expansion; With a raisin cake.When baking, the raisins in the oven do not expand, but the dough (= the room) in between. YES and that in turn means that the 46 billion light-years that the radius (=ObservableUniverse) measures of the observable universe only applies to the now!So let us stick to the raisin cake, which continues to rise and faster and faster and time does not matter, it does not have to be finished today. And because the cake goes, the universe expands continuously, the particle horizon continues to grow 鈥?and indefinitely.
Currently, the radius for the observable universe is precisely these 46 billion light-years.And it applies, of course, to every location within the universe, including the ones furthest from us. This is in the Hubblelaw and it is named after a human being, but not made and describes that the space expands evenly everywhere.The Hubble constant is when you use the current age of the universe (i.e. 13.8 billion years). This Hubble parameter currently has a value (which is also confirmed by measurements in space) of about 70 kilometers per second per megaparsec (1 megaparsec equals about 3 million light-years)
Do we want to leave it at that or should I try to explain it?
Sketch four dots on a piece of paper.One point represents our Earth, the other three each represents a galaxy. The distances in between are always exactly one light-year high. Now imagine that we let the room spread out at a speed of 100 km/s; from every point! As a result, galaxy A is away from Earth at 100 km/s. Galaxy B also distances itself from galaxy A at 100 km/s. And galaxy C is of course also away from galaxy B at 100 km/s. What do we then see from Earth? Galaxy B not at 50 km/s, but at 100 km/s + 100 km/s (=200 km/s); so twice as fast. And galaxy C is even three times as far away from Earth’s point of view. In a mathematical formula and have the Hubble parameter. And for us, it now seems that there are galaxies that move away from us at overlight speed, even though the light is always in a vacuum at around 300,000 km/s.Spreads.
But if the space expands faster and faster, there is a point somewhere where it expands “faster than the light”.Now the light must fly at a faster speed than it can reach itself. Imagine climbing into one lake and being an experienced swimmer, then you can estimate how long it will take you to reach the other shore. But now you go into a river in the Alps. It flows faster than you can swim. You never manage to reach the opposite shore in this place!The “light from the Big Bang” comes towards us at the speed of light; but at the same time” flies” everything away from us. So we are already here while the light is troting behind us! This, in turn, is why we can’t observe galaxies far away, but only theoretically know about them, and why we can only see the nearby galaxies that only move away from us at the lower speed of light.
Ok, but this leads to the question: how quickly does a volume of space in which a galaxy is involved have to move away from us that the light of this galaxy on Earth no longer reaches us? Logically, the volume of space must move away from us at the speed of light!The two light speeds do not rise to zero, but the light that reaches us is simply too slow for us to see and measure. Light now emitted by galaxies beyond the event horizon (i.e. beyond the radius of 16 billion light-years) can never reach us on Earth because the space between the galaxy and us is simply expanding too fast
This is the reason why galaxies seem to “rush” through space, even though everyone in space is more or less not “so doll”!And it does not touch the good well-known Einstein with his Special Theory of Relativity. Because it only makes a statement about how things can move in space.Despite the expansion of space, “Nothing flies faster in space than the light!”.
Since the expansion of space exists, we can never see the end of theuniverse, let alone reach the end of the universe.And because it will expand faster and faster, it will be so big in about 100 billion years that we will be alone with a few other galaxies (here). You can have a look!
If you now think that would be… B盲tschi would say a former party chairman.
Nikolaus von Kues (aka Cusanus) had already said almost 600 years ago, “The universe is a ‘sphere’ whose center is nowhere and around it.” This was demonstrated by the mathematician Bernhard Riemann, one of the founders of the nieuklid geometry.But it was only Einstein, with further mathematical evidence in the context of his General Theory of Relativity, that further foundations were laid for a world model that would create a space that was curved backwards as a three-dimensional analogue of a two-dimensional bullet surface. Let us transfer this to our Irish thoughts: the surface of our earth is finite, but unlimited. You could always go straight or swim 鈥?and would never come to the edge, but at some point back to where you left.Structures of the hypersphere
However, the comparison with the Earth, reduced by a spatial dimension, lags: On the one hand, one does not need to think of the hypersphere embedded in a higher-dimensional space, and one could not leave it or look at it from the outside.On the other hand, space is not static, but – as we have already read – since the Big Bang, but “inside”, does not extend into a hyperspace.
Although Einstein’s original model does not work because it is static, but space continues to expand, the hypothesis of the hypersphere has not been refuted to this day.It is even well compatible with the data in the context of measurement inaccuracies, if the inner “scope” of the universe is at least a few trillion light-years.
And then there are the theories of the inner appearances of the hyperspaces of Technicolor, the string theories and M-theory, whereby there are only “foams and bubbles”….which then bring to a halt all the dreams that one has until then has done so.Is it all made up of strings and is our universe of a bran embedded in other brans? An Introduction to String Theory.
Answer by Rolf A. Pira to What is String Theory?Is there an explanation for a layman like me that also a “normal citizen” understands?
….and there is still this stupid gravity that deforms the space and bends it.It may look like a Picardfunnel, i.e. an infinitely long, narrow funnel that expands into a kind of bell, but which is closed at the bottom.Consequently, the cosmos would be infinite in the direction of the funnel horn, but closed and would also have a limited spatial content. The sides of the funnel edge are topologically identical: if a spacecraft could travel there, it would fly straight back at the opposite “side”.So there is no “edge” to come across 鈥?difficult to understand for everyday viewing, but mathematically precise.
No matter how you look at it, you always come to borders that are infinitely wide and cannot be grasped and the question remains “What is after”. Icke wee脽 et nich!But no one else!
The universe is infinite.Infinite, however, is not a large number, not a quantity, as they say so beautifully, but a quality. If you multiply infinitely by 2, it still comes out infinitely. And if you pull off 50 of them, it’s still infinite. Infinite is not a number that can somehow be fixed. The universe is already infinitely large and expands within itself. This is indeed unimaginable, but there is no need for an edge where this extends.