I wanted to try to explain it without any scientific terms and sat there in front of a blank sheet.Because it can’t be done without it. Mea culpa!
Let us start with the universe; we also like to call it universe.Our universe.
Inevitably, however, there are certain ideas about this, 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 Big Bang 13.8 billion years ago, all the matter and energy of the universe (stop, I have already put it wrong: the universe itself, just EVERYTHING, and that was NOTHING) concentrated on a single point.And that was a POINT, and as you know, a point has no extension. As soon as the universe began to “rain”, space and time began. Because where something is NOT spatial, there is no time.
But now… The universe expanded, it’s not like blowing up a balloon (because you always have the idea of the OUTSIDE), but quite different.Where there was NOTHING, suddenly there was SOMETHING.
A “second” after this event, a colossal flash occurred (If we speak before Ur Knall, then please also of Blitz) in the whole universe.This flash can still be observed as a relic as cosmic microwave background radiation.
And all this we can “see” and what we see expanded and “distributed” the mass and energy evenly (with the exception of the Teeny-Weeny effect of gravity and quantum fluctuations, but we don’t care about that here).
Original lumps of matter and energy present in the newly born universe left an imprint.And from everything, lumps of matter, stars, star systems and galaxies and galaxy clusters developed. And over and over again.
As the universe continues to expand, they all race away from each other, seemingly fleeing from each other.And because of this (apparent) flight movement, one could be tempted to calculate back where they were originally. But that would only be an idea and mathematical interpretation. However, this point is not the starting point of the extension!
The Big Bang was not a placefrom which everything came from.The Big Bang was not a special place in the room where a monument could be erected ” HERE THEUNIVERSUM“, but rather the origin of the space. Seen in this way, the Big Bang took place everywhere 鈥?also here in Frankfurt.
According to the latest scientific knowledge, the observable universe manifested itself with the Big Bang 13.8 billion years ago.And immediately we take a break, because we have to explain again; the term “observable universe”.
I had already explained above that the space has spread from any place (e.g. Frankfurt am Main) in all directions of our observation.Since nothing is faster than the light – as the questioner himself pointed out, one would suspect that one would see objects around us up to a distance of 13.8 billion light-years”.
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 radius is also called particle horizon or observation horizon.It is calculated taking into account the probable amount of matter in the universe, Einstein’s cosmological constant, and the Hubble constant (see below).
In short, we can see light today that was emitted by atoms more than 13 billion years ago (well, probably only a few hundred thousand years after the BigBang) and is therefore also a good 13 billion years old.However, these very atoms that sent this light at that time are now much, much further away from us 鈥?not 13.8 billion light-years, but 46 billion light-years.
The reason for this discrepancy is the continuously accelerated expansion of the universe and we have to note that not anything flies from a formerly central point since the Big Bang, but the space itself expands!
Bakers may well imagine this; With a raisin cake.When baking, the raisins in the oven do not expand, but the dough (= the room) in between.
This in turn means that the 46 billion light-years that the radius (=particle horizon) of the observable universe measures 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 just 46 billion light-years. And, of course, it applies to every location within the universe.
The Hubble Law is based on this fact that space expands evenly everywhere, even though all galaxies in space are more or less not moving at all!But because Einstein’s Special Theory of Relativity makes no statement about how space canexpand, but only how things can move in space, an overlight-fast relative velocity caused by space expansion is not in the Contradiction to the statement “Nothing flies faster in space than the light!”.
And now think again:
- We 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.
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.
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.
Now transfer this to a mathematical formula: which describes the so-called Hubble parameter.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).
So it seems to us that there are galaxies that move away from us at overlight speed.Light – as we have learned – always spreads in a vacuum at around 300,000 km/s. used to express the starting point of a movement.
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 everything flies 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.
In short, we can only see those events in a galaxy from Earth that took place in that galaxy before the event horizon was exceeded
However, we can calculate the associated distance at which exactly this occurs: Hubble Radius D (t) = Speed of Light divided by Hubble parameter H (t).So: 300,000 km/s divided by 70 km/s per megaparsec = 14 billion light-years.
Now we also have to look at the so-called event horizon.This is located outside the Hubble sphere just described (radius = 14 billion light-years), but still within the observable universe (radius = 46 billion light-years).
This horizon exists because the universe not only expands, but expands morequickly.And he kind of tells us something about the future. Namely, how far an object can be as far away from us today as possible, so that its light can reach us in principle at some point in the infinite future.
One might now assume that this event horizon coincides with the Hubble sphere, because light particles can never reach us when they are emitted in an area that distances itself from us at “superlight speed”, namely beyond the Hubble sphere. .
Caution!Researchers have also found that the Hubble sphere will grow a little in the future, and the distance at which objects move away from us at the speed of light increases to l 16 billion light-years.
It is generally true that objects and events beyond the event horizon are not directly connected to us, so that no information can reach us from there.This also applies in the opposite direction.
From this we conclude: The universe will be so big in about 100 billion years that we will be alone with a few other galaxies (here).Everything else is already behind the cosmic event horizon.
Has this now become so comprehensible “Why do we see objects (the Big Bang) that were “here”long before us and with the pseudo – overlight speed?It’s all relative!
Sorry… may have become a little too awkward…..
P.S. There are thinkers who see in the Big Bang and the expansion something like a “bush fire” where something burns and a new seed comes out of it.Or an infinitely large foam in which bubbles bubble, grow bigger, burst and new ones emerge.
irrelevant!On my doorstep I probably make a new sign “Home of Rolf A. Pira – ORIGIN OF THE UNIVERSUMS”.