# Where is the coldest place in the universe at present? This place has a very nice name

I believe we are not unfamiliar with temperature. We are dealing with it all the time. The origin of temperature comes from the big bang of the universe. Since the singularity explosion 13.8 billion years ago, the universe was born, along with the birth of space, time, temperature and other cosmic rules.

Although temperature is something that human beings touch every day, people in ancient times only knew the temperature was high or low, but they didn’t know how to measure the temperature, and they didn’t know whether the temperature had a limit value. With the continuous development of mankind, 300 years ago, human civilization entered the era of scientific and technological development. In order to better study and explore the mystery of temperature, scientists defined a measurement standard for it: centigrade.

Centigrade is divided into above zero and below zero by 0 degrees. With this standard, scientists have begun to explore and study the temperature. Now we all know that there is no upper limit for temperature. It can rise infinitely, hundreds of degrees, thousands of degrees, tens of thousands of degrees or even hundreds of millions of degrees. However, the temperature has a lower limit, which is absolute zero, that is, 273.15 degrees below zero.

The reason why there is a lower limit of temperature is to start with the micro particles that determine the temperature change. Scientists say that the reason why the temperature changes is because of the internal molecular motion. When the molecular motion becomes more and more intense, the temperature will continue to rise, and when the molecular motion becomes weaker and weaker, the temperature will continue to fall.

There is a lower limit for the weakening degree of molecular motion, that is, static. When the molecular motion is completely static, the temperature drop will reach the limit. As a matter of fact, the motion of molecules can not be completely stationary, so absolute zero is only an unattainable target, which can only be approached but not reached. This is very similar to the speed limit of an object, which is the speed of light.

Since the temperature came from the big bang, the temperature of the universe should be very low. Where is the lowest temperature in the universe? Although there are many stars like the sun in the universe, which can bring some warmth to the cold universe, the temperature of the background radiation temperature of the universe is always very low. The average temperature of the universe is about minus 270 degrees Celsius. Of course, the temperature of different places in the universe will be different.

At present, the coldest place in the universe observed by scientists is the Boomerang Nebula, which is 5000 light-years away from the earth. It is located in the constellation Centaurus. The temperature of the nebula is only about one degree higher than absolute zero, and the temperature can reach minus 272 ℃. In fact, the Boomerang Nebula is formed when a star peels off gas at the end of its life. Some people may still have a question: there are many nebulae formed at the end of the life of stars in the universe. Why is the temperature of the Boomerang Nebula the lowest?

In fact, all this is mainly related to the special shape of the Boomerang Nebula. The shape of the Boomerang Nebula is like a bow tie, which is caused by strong winds with a speed of 310000 miles per hour (about 500000 kilometers per hour). The ultracold gas is far away from the dying central star. Its structure is similar to a trumpet, with a small mouth and a very small gas discharge speed. In this case, the air is rapidly squeezed to do work outward, resulting in adiabatic expansion, which accelerates the air cooling. In fact, we can often see this point in real life. For example, if the airflow is rapidly ejected from a very small mouth, it will be very cold at the tuyere. There are many cold places on the earth, which is similar to this.

However, scientists believe that the Boomerang Nebula can not always maintain its position as the coldest place in the universe. As time goes on, the dust of the whole nebula is still spreading, and the surrounding dust is receiving the irradiation of other stars. Such irradiation brings them warmth, so the outer side of the nebula is gradually warming up. Although it is still lower than the temperature of the surrounding space, it will be in the near future In the future, the trend will gradually be consistent with the background temperature of the universe, and the coldest part of the universe will be replaced by other special nebulae.

In fact, it is still unknown whether there are colder places in the universe than the recoil bar nebula. Although modern scientists say that the Boomerang Nebula is the coldest place in the universe, the prerequisite is that it is within the observation ability of existing technology. The universe is so vast that we can’t imagine it. Although human beings claim that the observable universe can reach 92 billion light-years, in fact, the scope of the universe we can really observe is very limited.

In the vast universe, the existing observation technology of human beings, in addition to super massive black holes, quasars and other objects with extremely bright energy, can be observed by us in tens of millions of light years or even tens of billions of light years. For other ordinary objects, such as stars, planets, nebulae and so on, we can observe no more than 10000 light years.

Therefore, scientists have no definite answer to where the temperature of the vast universe is the lowest. According to the normal logic, the farther away from the center of the universe, the colder it should be. Then the edge of the universe may be the place with the lowest temperature. However, with the development of science and technology, we can’t observe the edge of the universe, or even the size of the universe We’re just guessing.

It is doubtful whether absolute zero is the lower limit of temperature. Although absolute zero is the truth under current technology, it is still unknown whether it can maintain the absolute lower limit of temperature in the future. It is possible that with the continuous progress of human science and technology, in the future, we can create a temperature lower than absolute zero in the laboratory, then the lower limit of temperature will be broken, and in the universe, there may be the lowest temperature beyond our imagination in the unknown region.

Although temperature is something we touch every day, we don’t know much about it. It’s the same as time. Although we deal with them every day, all about them are only human’s own definition. How to define the real temperature of the universe still needs constant research and exploration by scientists. It is possible that in the future, we will be able to completely solve the mystery of temperature. At that time, human beings will not be far away from truly revealing the ultimate mystery of the universe.