If you think about it carefully, it is inevitable that there will be such a question: Why is there such a perfect nature, a universe that can't have any differences? If not, will everything collapse? The problem of fine-tuning can be traced back to Stephen Hawking's research in 1970s. He thinks like this: if I disturb the universe a little when it is born and give it more or less energy, what does it mean for the long-term development of the universe? In fact, when the mass of a universe is great, it will collapse again.
After the initial expansion, mass (that is, gravity) will shrink the universe, and then collapse back to 0. This is the so-called circular universe. It always repeats its own growth and death process. There is another saying: the universe began with expansion, but it is so light that gravity can bring back the expanding self and separate it! Then there is a variation between the two. These statements are all right. The universe will start with expansion and then continue to expand. In this universe, it will continue this cycle.
Later, Hawking discovered that we must fine-tune the universe. It looks like a ballpoint pen is standing on the nib, but if a ballpoint pen is standing on the nib and the nib is not standing on the table, it will stop. The probability of pen stopping is almost zero. Of course, such a thing will not happen. It doesn't just stop on the plate, it also stands on the blade. And this blade stands on one blade, another blade stands on one blade, and the other blade stands on one blade. People may think that there are 10 55 blades against each other, and the ballpoint pen against them is standing and will not stop.
The universe is so harmonious that it naturally challenges scientists. It can't be so perfect! There must be something undetected. Some researchers believe that this is not the case and we need to continue to think deeply. There may be 10 500 parallel universes. The universe is too heavy to rolling in the deep. The other one is too light and flies too far. Therefore, our environment is a combination of natural constants and natural laws, which also makes us what we are today.
Therefore, at least one day, there may be other life outside our universe. Although there is no time and no origin of the universe, we can say that there is a multiverse. This is a super universe, in which all universes will appear. Or they were born at the same time as our universe. It's just that some places are a little different, so none of them survived. As I said, some have flown away and some have collapsed.
This is actually an empirical explanation, because many observations cannot be explained by an excessive expansion. This excessive expansion is called "inflation". What is skyrocketing? Inflation is over-inflation. This is the sudden accelerated expansion of the whole universe after normal expansion. Obviously this happened after BIGBANG. The big bang occurred after 10 to 43 seconds, while the inflation was 10-30 seconds. So there is a pause between the two. Before that, the universe was stable and then it was disturbed. And then bang! The universe is 50 orders of magnitude apart in time 0.
What kind of universe is that? We can observe that the universe is obviously flat, flat like a plate, except for the well house-they are all caused by the existence of matter. General relativity tells us that the existence of matter will bend space-time. Where the quality is high, there is time and space. But if you average it all, it will be as flat as a board in the long run. A flat three-dimensional object is flat everywhere. It may be a very big sphere. The universe is so big that it can be measured by billions of light years.
Then came the concept of inflation. But if so, you have to ask: Is there any mechanism to explain it? Of course there is. Switch to our world: this is about supercooling. Water is normal. When it is below 0 degrees Celsius, it starts to freeze from top to bottom. This is an obvious fact. If it gets colder and colder, it will start to freeze. But if you are cold so slowly that the water will not notice the temperature drop, then the water will remain liquid. The world record is far below MINUS 20 degrees Celsius, but this is of course wrong.
So what is wrong? Even the smallest disturbance can freeze water. This freezing will naturally release energy. The free energy of water molecules once locked in the crystal is suddenly released. These energies will be released into the universe, causing the universe to over-expand. Perhaps there is another hint: the concept of inflation is based on an idea. This idea is the concept of scalar field. Scalar field is a ubiquitous and direction-independent field. This is an explanation of the theory we have found so far. Since 20 12, we have known that there is such a scalar field called Higgs field. At the beginning of the expansion of the universe, this field may have undergone the above transformation.
This will establish a huge connection between the largest cosmology and the smallest elementary particle physics. Now we can reconnect the two. Maybe we will have the idea that fine-tuning may lead to the fact that once you put the ballpoint pen on the shaving blade, it will stop there. This is incredible! But obviously, if all this happens in a super universe again, then other universes may also experience expansion with our universe. They soon fell under their own weight.
Other universes have also stopped for a long time-expanding. We can't answer all these questions about what is outside our universe and what was before the beginning of the universe. Because we are empirical scientists. We try to gain insight from experience, that is, to discover truth with experience. These discoveries always appear in such a way that people try to measure something by observation. In this way, today we know that there may be parallel universes. This is our universe, extraordinary and irreversible. In this way, from 65.438+0.382 billion years, a time arrow appeared in the universe. It keeps moving forward and never looks back.