*~*Disclaimer: The following theory is put forward all by myself. The contents may or may not be true. *~*
I hope you would have read my previous topic, ‘How Old is Everything’. There I explained how the age of the Universe was estimated to be between 11 to 18 billion years. In this topic I’m not going to tell you that the Universe has a limit or that there is a perfect boundary for the Universe but I’m going prove that one cannot see anything in the Universe beyond a particular range which could form an invisible boundary.
Before explaining my theory let me start with the basics. I hope you all would have heard of the term ‘Light Year’. It is the distance traveled by light in one year. Now imagine you see a star which is 10 LY (Light Year) away. The light from the star that you actually see was produced from the star 10 years ago. It has taken 10 years for the light to travel from that star all the way to Earth. Based on this there are three possibilities on whether you can see a particular star.
1. Now let us imagine a star which is 10 million LY away. If the star was alive 10 million years ago then we will be able to see the star at present as the light produced from the star 10 million years ago would reach the Earth at the present time. I hope there is no doubt about that.
2. Now let us assume that the star (10 million LY away) was not present 10 million years ago. Let the age of the star be 1 million years old. Though the star does exist at present we would not be able to see it from Earth because the light of the star will take 9 million more years to reach Earth.
3. Now let us imagine that a star (10 million LY away) did exist 10 million years ago but it does not exist at present. Let us assume that the star died about 5 million years ago. Yet we would be able to see the star. Only after 5 million years we would be able to see the star die from Earth.
My theory is based on these three points. Once you understand these three points, you would be able to understand my theory.
Coming to the point, let us assume that the Universe is 1 billion years old and there was no source of light before that. Let us assume that there is a star 1 billion LY away and that it was present right from the beginning of the Universe. Then we can surely see that source from Earth. Now let us assume that there is a star which is 2 billion LY away. We would not be able to see it because the star was not present 2 billion years ago. Since that was before the birth of Universe, there was nothing in the universe at that time. Hence we can see nothing beyond the range of 1 billion LY since there was no source of light at that time. Thus our range of sight is only up to 1 billion LY is all direction.
Therefore I conclude that though Universe does not have a definite boundary, it certainly has a limit beyond which nothing can be seen, whether or not something is present. And this limit is given by the age of the Universe. Hence every second, the limit is further extended by 1 light second (3x10^8 meters). Hence every year, the limit is extended by 1 LY. Is this what the scientists say that the Universe is expanding??? Or is it just a coincidence???
The object within the white circle is the farthest object ever discovered. Abell 2218 is a tiny galaxy at a distance of roughly 13 billion LY from Earth
Here is another point I have discovered. Using the above theory one can say that the limit of the universe is approximately the age of the universe itself. And one cannot see anything beyond this range from Earth. By theory of relativity, it can also be said that the Earth is in the center of this boundary or relatively Earth is at the center of the Universe.