universe limited , or infinite ? The issue of
has been debated endlessly.
Some people think that the universe has a limit, because the maximum limit that the Hubble Telescope can see is about 
2 billion light years, which should be the limit of the universe.
However, some people object. They believe that these 92 billion light years can only be called the boundary of the field of view , and is not the real boundary of the universe .
Hubble Space Telescope
For example, why the ancients thought that the sky is square and the earth is round, because standing on the ground and looking at from a distance, they would think that the junction of the ground and the skyline is the boundary of the earth.
In fact, it's just what people can see. In the same way, the Hubble Space Telescope uses optical , so there will be " vision " restrictions.
In order to find out, we explored in many ways whether there is a boundary in the universe.
Does the universe have a boundary?
Discussion on the boundary
As for how the universe was born, most scientists support the Big Bang theory, believing that the universe was created by the explosion of a singularity.
If this is the case, then the boundaries of the universe must be determined based on the shape of the universe .
If the universe is a spherical , then the universe is with bounded ; if the universe is bell-shaped or trumpet-shaped , there is no boundary in a certain direction.
is like ray . Starting from one point, can extend infinitely to at the other end.
We may be able to find that point, but we can never find the other point.
The Big Bang
Theoretically, it is possible to find the starting point of the explosion , but we can never find the end point of the explosion .
but space is produced by the expansion of the universe. There is space only where it has expanded. There is another phenomenon that shows that the universe has boundaries, but we cannot see , that is the expansion of the universe .
Hubble Telescope is an optical telescope . Only where the light reaches can be observed by it.
And the 2 billion light-years it observed can only show that the light reached there. It cannot be observed in other places, not because it does not exist, but because light has not yet gone to .
If the expansion speed of the universe exceeds the speed of light , then light will never catch up with the boundary of the universe , and human vision will always be one step behind the real boundary.
Schematic diagram of the expansion of the universe
Looking at it this way, the issue of the boundary of the universe becomes very contradictory , because as seen by the Hubble Telescope, is not the entire universe , and can only be called the " visible universe ".
The invisible universe never knows where its boundaries are, so to a certain extent, the universe is with edges but unbounded .
If you want to prove the boundary of the universe, you can only catch up with the pace of the expansion of the universe and go to the forefront of the expansion to know whether there is a limit.
It is worth noting that the Big Bang is only a hypothesis for the origin of the universe, and time and space are not necessarily caused by the explosion.
I am afraid that the limits of the universe will become an unsolved mystery along with the existence of the universe.
Multiverse
Zoom in on the universe
When observing the universe at the size of billion light years , take a picture 1 billion light years away, and you will see dark space , some sparse light spots , Some of them are brighter and some are darker.
At this time, we enlarge the picture and fix the scale as 1: when is 100 million light years, there will be dense light spots of appearing in a certain area of .
, they seem to form a system of , "close" together, and next to them, there are still sparse light spots.
Continue to zoom in, and enlarge the scale to 1:10 million light years . We can see that the points in the space are brighter . These points are not separate stars , but galaxies , including our galaxy .
light years away
When the ratio is enlarged to :1 million light years , we can see that the outline of the Milky Way appears in the picture.
At this time, Galaxy takes up about one-tenth of the photo.
When the scale is enlarged to :100,000 light years , the Milky Way occupies the entire picture, and we can clearly see its spiral arms , and halo .
This is the Milky Way we are in now, with a diameter of about 100,000 light-years .
If we continue to zoom in, the ratio reaches :10,000 light-years . We see that in the entire picture is densely packed with dots , which are the stars in the galaxy.
Milky Way
Our solar system is one of these dense objects, and trying to find it is like looking for a needle in a haystack .
At this time, you need to increase the magnification to find the solar system faster.
We can directly adjust the ratio to :100 billion kilometers . We can see that the outline of the solar system has appeared. The solar system at this time is similar to the Milky Way at 1:1 million light years. .
The position of the solar system in the Milky Way
When the ratio is expanded to :10 billion kilometers , the entire solar system can be seen. The eight major planets , asteroids, the Kuiper belt , etc. will all appear in the photo. When the
ratio reaches :100 million kilometers , the earth appears in the photo. If we continue to zoom in, we can see the landforms and scenery on the earth, and even the people on it.
Seeing this, we can look at another kind of picture - the magnified picture of life.
The relationship between stars and planets in the solar system
The universe and life
Let us take people as an example. There is a person standing in a photo. When the photo is enlarged 10 times, we can see part of the person.
continues to zoom in until and fill the entire screen.
If we continue to zoom in, we can clearly see the veins, folds, ravines, etc. on the skin.
Then zoom in and we can see epidermal cells and cuticle . After that, if you zoom in, it will be cell structure , then cell nucleus , mitochondria , and finally the molecule , and finally the atom .
Fingerprint enlargement
Do you feel scared to think about it? The structure of the universe is exactly the same as the structure of life.
If the universe is compared to a living body, then the major super galaxies are organs , and the galaxy is the cell group that constitutes the organ.
The solar system is a separate cell . The earth is just a part of this cell, not the nucleus. The nucleus is the sun. The earth should be counted as mitochondria .
Then we humans are DNA that make up mitochondria.
Looking at it this way, all things in the universe must follow the order of from small to large .
Cells under the microscope
First there are atoms, and then they form various molecules in the universe, such as various gases, which form nebulae. The gas, dust, and atoms in the
nebula continued to aggregate, forming the early celestial body . After
, the celestial bodies combined to form the earliest star galaxy , and the galaxies then formed the Milky Way . The
Milky Way galaxy forms the supergalaxy due to the surrounding galaxies. Finally, the supergalaxies form the universe .The process of converting
into life is that at the beginning, polymers organic matter were aggregated at the vents of submarine volcanoes. Some of the organic matter decided to combine, thus forming the original life form .
The nebula in the universe
life forms further aggregated to form the cell structure , and the earliest eukaryotic cell was born.
It’s just that at this time they are all single-cell organisms , similar to independent celestial bodies one after another.
One day, eukaryotic cells came together to form multicellular organisms. Finally, different types of cells were formed, and the forms of life became more and more diverse.
There are even six major schools: , the animal kingdom, the plant kingdom, the fungus kingdom, the protist kingdom, the prokaryotes kingdom, and the virus kingdom . It can be divided into many small sects.
The course of life is, to a certain extent, a replica of the formation of the universe.
DNA that exists in all living things
Human beings and the universe
It can be seen from this that human beings are just a kind of substance in the universe, an organic substance. We are really too small for the universe.
Let us return to the original starting point: Does the universe have a boundary?
This problem is like the mitochondria in the human body wanting to leave the human body, so they are constantly looking for the boundaries of the human body within the cells.
Human body size is limited, and of course there are boundaries. But the question is, can mitochondrial material leave the human body?
Or, if one person's mitochondrial DNA enters the body of another organism, can it continue to survive?
Mitochondrial DNA
It’s very scary to think about it. We always say that we want to leave the earth to realize interstellar immigration , so how do we break through the constraints of the earth on us?
Human beings go to live on other planets, just like mitochondrial DNA leaves the human body and goes to other creatures.
This creature may not be an animal, it may be a plant or even a prokaryotic organism. Some organisms do not need mitochondria at all.
In the 1980s, scientists built a "biosphere 2" in the desert in an attempt to simulate the earth's ecology, but ended in failure. The
experiment tells humans how important the earth is to humans. The earth can live without humans, but humans cannot live without the earth .
Human beings cannot live without the earth
So, is the boundary of the universe really so important?
