overview
The sun emits a steady stream of light and heat to the universe through the nuclear fusion reaction in the core. In addition, the earth always revolves around the sun, so there are changes and alternations of cold and heat throughout the year on the earth.
As one of the hundreds of millions of creatures on the earth, we have the most intuitive feeling about high and low temperatures. For example, when the coldest winter comes, the temperature in the northeastern region can be lower than minus 20℃, and when the summer is the hottest, the temperature in the south can be close to 40℃.
From the perspective of the temperature limit, this is just a very small temperature range. Scientific research has found that the lowest temperature, absolute zero, is -273.15°C, but the highest temperature has reached 140,000,000,000,000,000,000,000,000,000,000°C.
It seems that the lowest temperature is not very low, but the highest temperature is such an alarming number. Why is this?
The nature of temperature
To understand this problem, first we need to know the nature of temperature.
Einstein proposed the famous "time-slow scaling effect" theory in his special theory of relativity . In this theory, he explained the relationship between time and material motion . To put it simply, the faster the movement speed of an object is, the shorter the time it takes.
In fact, not only is time closely related to the movement of matter, but the generation of temperature also originates from the movement of matter. In other words, The essence of temperature is the movement of matter. "Frictional heat generation" is a very typical example.
We know that everything is composed of microscopic particles, so from a microscopic perspective, temperature reflects the intensity of the thermal motion of the particles.
When the thermal motion of the particles is fast, the temperature of the material will be relatively high ; when the thermal motion of the particles becomes slower and slower, the temperature of the material will continue to decrease; when the particle motion completely stops, the temperature of the material will reach the lower limit, which is absolute zero.
Minimum temperature: absolute zero
Theoretically, there is absolute zero in the universe, but in reality, absolute zero can never be reached and can only be infinitely close.
Scientific research has found that the average temperature of space is -270.15℃, is very close to absolute zero, but it can never reach absolute zero.
From the nature of temperature, when the kinetic energy of particles reaches zero, it will reach absolute zero and all energy will disappear. Therefore, Unless there is no energy and heat in an object or a certain space from beginning to end, it will never reach absolute zero.
However, after the singularity explosion, energy and heat are moving everywhere in the universe, so the universe can never reach absolute zero.
So, was the "nothingness" before the big bang in a state of absolute zero? The answer is also no.
Here we have to mention a basic principle in quantum mechanics , which is the "uncertainty" principle, also called the "uncertainty" principle, which was proposed by the German physicist Heisenberg in 1927.
"It is impossible to know the position and momentum of a particle with high accuracy at the same time. - Heisenberg"
According to this principle, we cannot measure the momentum and position of the quasi-particle at the same time, and If the particle is stationary, then we can know its position and momentum at the same time, which breaks the "uncertainty" principle.
Therefore, even at absolute zero, the particles will vibrate rather than stand completely still. In other words, no matter whether the movement is fast or slow, the particles will never stop. Absolute zero is only a theoretical lower limit of temperature. In reality, such a temperature does not exist.
Maximum temperature: Planck temperature
- Is there an upper limit to the temperature?
For humans, the sun is synonymous with the highest temperature. The temperature of the sun's core is as high as 15 million degrees Celsius, and the surface temperature is nearly 6,000 degrees Celsius. There are many stars in the universe with masses and temperatures exceeding the sun.
In this case, I wonder if you have thought about this question: Is there an upper limit to the temperature in the universe we live in?
Theoretically speaking, there is no upper limit to the temperature, but the temperature will have a critical value. Even if the temperature is higher, will be meaningless if it exceeds the critical value.
This temperature limit is the "Planck" temperature. Any substance higher than the Planck temperature has no meaning in existence. Exceeding the "Planck" temperature, our physical laws will become invalid, and no concept will exist except gravity.
So, how is the Planck temperature obtained?
- Planck temperature
In fact, the Planck temperature is derived by scientists based on the calculation formula, as shown in the figure below.
In this formula, Tp represents the Planck temperature, c represents the speed of light in vacuum , and the speed of light is the limit of speed in theory. Therefore, the calculated value of is about 1.4 billion trillion billion degrees Celsius, which is naturally set as the upper limit of temperature.
So, will the Planck temperature be the same as absolute zero, just a value that exists in theory but will not be reached in practice?
Of course not, although we can't see the Planck temperature in the current universe, it has reached 1.4 trillion trillion billion degrees Celsius in the first moment of the Big Bang .
After the Big Bang, the temperature of the universe has been cooling as time goes by. It was not until 300,000 years later that the temperature of the universe cooled down enough for light to appear. As of now, the temperature of the universe is close to absolute zero.
Having said that, how terrifying would it be at 1.4 trillion trillion degrees Celsius?
To understand the power of the Planck temperature, we still have to find the answer from the Big Bang.
According to Einstein's mass-energy equation, we know that matter and energy can transform into each other , but we can see matter transforming into energy, but we cannot see energy transforming into matter. Why is this?
In fact, this is because the energy value does not meet the requirements for conversion into matter . Our current universe is transformed from an instant burst of super energy.
At the first moment of the Big Bang, a high temperature of 1.4 trillion trillion degrees Celsius was generated. This super energy was converted into various substances in the universe.
What you need to understand is that the universe was created at a temperature of 1.4 trillion trillion or more, so this also means that at such a temperature, the universe can be destroyed in an instant.
Conclusion
It is obvious that both absolute zero and the Planck temperature are extremely powerful and terrifying existences.
The absolute zero of minus 273.15℃ means that all particles are stationary, and any heat and energy will no longer exist.The concepts of time and space will also disappear, but fortunately, our universe will never reach absolute zero.
The Planck temperature is also powerful enough to form the universe. If humans can thoroughly study the Planck temperature in the future, perhaps we will have the ability to convert energy into matter, and then humans may truly become the "gods" of the universe.
