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The mystery of absolute zero: Why does matter stop at this temperature?
In physics, absolute zero is defined as 0 K, an absolute thermodynamic temperature scale corresponding to −273.15 °C in Celsius and −459.67 °F in Fahrenheit. This is the theoretical limit in nature that corresponds to the lowest temperature at which all particle motion of any substance will cease completely. Absolute zero is not only a physical challenge but also a profound test of our understanding of the nature of matter as we try to understand this strange phenomenon.
Why does matter become almost completely stationary under such extreme conditions?
From a microscopic perspective, the movement of matter mainly comes from the thermal energy between particles. As the temperature decreases, the movement of particles gradually slows down. Once it reaches absolute zero, according to the theory of classical physics, the vibrations and movements between these particles will completely stop, causing matter to seem to enter a state of rest. However, in the description of quantum mechanics, matter actually still has zero point energy, even at absolute zero. Therefore, the answer to this question is not simple, and the real situation involves a deep understanding of quantum physics.
The cooling process
Cooling is the process of cooling an object or lowering its temperature. This process can be accomplished by removing heat from the system or by exposing the system to a cold environment. Common cooling methods include air cooling, contact with ice, dry ice or liquid nitrogen. These methods use the principle of conduction to transfer heat from a relatively warm substance to a relatively cold coolant. In addition to traditional cooling methods, scientists have also developed technologies such as laser cooling and magnetic evaporative cooling to reach low temperatures close to absolute zero.
Historic cooling technology
In early times, ice was used primarily for cooling drinks rather than preserving food. Some records from Roman times indicate that people in ancient Egypt and India also discovered techniques for cooling down at night through the evaporation of water. As time goes by, cooling technology gradually develops, and the effective use of ice becomes more and more mature. Especially in the 17th and 18th centuries, many scientists began to explore the principles of cooling, and then introduced new cooling equipment such as refrigerators, changing people's lifestyles.
Effects on the human body
Low temperature has a direct and profound impact on the human body. Cold environments may cause some physiological and pathological effects, such as frostbite of the body and obstruction of blood circulation. When the human body is exposed to extreme cold, the initial physiological response is often shivering. This is the body's natural response to cold stimulation and is designed to increase internal heat to maintain body temperature. However, prolonged exposure to cold conditions can result in serious consequences, such as frostbite, shock, and even death. These responses fully demonstrate the important impact of cold environments on organisms.
Myths and misunderstandings about coldness
Some popular misconceptions are that cold weather can cause illnesses such as colds, but there is currently no scientific evidence to support this. Instead, these disease trends are more directly related to winter lifestyle habits, such as spending more time indoors. This discovery once again emphasizes the need for scientific understanding and how to properly view the impact of cold on our lives.
The limit of cold
The coldest object currently known is a state of matter called a Bose-Einstein condensate, which can reach temperatures as low as 170 nK. According to recent research, the National Institute of Standards and Technology even managed to reduce the micromechanical drum to 360 microkelvin, a record-breaking achievement that shows the advancement of science in ultra-low temperature technology. At the other end of the universe, the average surface temperature of the cold star Sedna can reach −240 °C, still continuing to challenge our understanding of extreme cold.
How will the nature of matter change under such extreme conditions?
As we explore absolute zero, both historical tracing and current scientific discoveries make people think about the nature of matter and how humans can use this knowledge to improve our lives. Therefore, as scientific explorers, we should reflect on: When faced with the coldness of the universe, what new revelations and understandings can human wisdom bring?
