The concept of “cold” is something that is commonly understood in our day-to-day lives. It is usually associated with a sensation that we feel when the temperature drops below a certain level, and it is generally considered to be the opposite of “hot” or “warm.” However, when we talk about the coldest thing on earth, we are referring to something that goes beyond our normal experience of cold.
Before we can answer this question, we need to define what we mean by “cold.” The temperature of an object is a measure of the average kinetic energy of its particles. When the particles in an object are moving more slowly, we perceive the object as being colder. The temperature scale we use to measure temperature is the Kelvin scale, which is based on the behavior of gases at different temperatures. At absolute zero, which is the lowest possible temperature that can be achieved, the particles in an object have no kinetic energy at all.
With that in mind, let’s explore some of the coldest things on earth.
The Boomerang Nebula
The Boomerang Nebula, also known as the Bow Tie Nebula, is a planetary nebula located about 5,000 light-years from earth. It is named for its unique shape, which resembles a boomerang or a bow tie. The temperature of the gas in the nebula is estimated to be around -458 degrees Fahrenheit (-272 degrees Celsius), which is just one degree above absolute zero. This makes it one of the coldest places in the known universe.
The South Pole
The South Pole is the southernmost point on earth, and it is located in Antarctica. The temperature at the South Pole can reach as low as -100 degrees Fahrenheit (-73 degrees Celsius) in the winter months. This is due to the extreme conditions in Antarctica, which include high altitude, low humidity, and a lack of sunlight.
Liquid Helium
Helium is a gas at room temperature, but when it is cooled to very low temperatures, it becomes a liquid. Liquid helium is used in a variety of scientific applications, including cooling superconducting magnets and studying the behavior of matter at very low temperatures. The temperature of liquid helium is just 4.2 Kelvin (-452.07 degrees Fahrenheit or -268.93 degrees Celsius), which is very close to absolute zero.
The Boiling River in Peru
The Boiling River in Peru is a unique geological phenomenon that is caused by geothermal activity. The water in the river is heated by volcanic activity, and it can reach temperatures of up to 212 degrees Fahrenheit (100 degrees Celsius). While this may not seem like a “cold” thing, it is actually one of the coldest rivers in the world in terms of its temperature gradient. The water at the surface is hot enough to boil, while the water at the bottom of the river is near freezing.
Superfluid Helium-3
Helium-3 is a rare isotope of helium that is used in a variety of scientific applications, including nuclear magnetic resonance imaging (MRI). When helium-3 is cooled to very low temperatures, it becomes a superfluid, which means it has zero viscosity and can flow without any resistance. The temperature at which helium-3 becomes a superfluid is just 2.17 Kelvin (-456.8 degrees Fahrenheit or -271.6 degrees Celsius), which is very close to absolute zero.
The Cosmic Microwave Background
The cosmic microwave background (CMB) is the radiation left over from the Big Bang, which occurred approximately 13.8 billion years ago. The temperature of the CMB is just 2.725 Kelvin (-454.765 degrees Fahrenheit or -270.425 degrees Celsius), which is very close to absolute zero.
