The Coldest Matter in the Universe Exists Right Here on Earth
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Chapter 1: The Unimaginably Cold
If you think that the chill of an Antarctic winter or the rapid freeze of liquid nitrogen is remarkable, prepare to be amazed. Researchers have engineered a temperature so frigid that it defies comprehension.
In 2022, a team from Kyoto University in Japan and Rice University in Texas managed to cool matter in a lab in Kyoto to within one billionth of a degree above absolute zero. This temperature is three billion times colder than the dark, voids of interstellar space, making it the coldest matter known to exist.
The scientists began their experiment with fermions from the rare-earth metal ytterbium. Fermions are a category of subatomic particles that include protons, neutrons, electrons, neutrinos, and quarks. By utilizing lasers, they restricted the movement of 300,000 atoms within an optical lattice, which consists of light-formed crystals that trap atoms at low temperatures.
Cooling atoms to such extraordinary levels allows researchers to explore the physics that occur at these extreme temperatures and observe phenomena that are purely quantum mechanical. These quantum behaviors would remain invisible under typical conditions, akin to pausing a movie to examine a particular scene in detail.
This matter holds the title of the coldest in the universe since interstellar space never reaches such low temperatures. This space is permeated by cosmic microwave background (CMB) radiation, a remnant of the Big Bang, which keeps photons evenly distributed throughout the cosmos. The temperature of these photons is approximately 2.73 Kelvin, making space itself warmer than the conditions achieved in the Kyoto laboratory.
However, there is one location in the universe that is notably colder: the Boomerang Nebula, located in the Centaurus constellation, about 5,000 light-years from Earth, with a temperature of 1 Kelvin. This region is believed to be chilled by gas expelled from a dying star at its center.
More Facts About Extremely Cold Matter
The scientific pursuit of extreme cold is not new. In 2015, a team at the Massachusetts Institute of Technology (MIT) cooled sodium-potassium gas molecules to an astonishing 500 nano-Kelvin, just 500 billionths of a degree above absolute zero. They accomplished this by using lasers to siphon heat from individual gas molecules, marking the first instance of chemically bound matter being cooled to such low temperatures. Although the resulting molecule lasted merely 2.5 seconds, it was a significant achievement in physics.
On the International Space Station, the Cold Atom Lab has been employed to investigate the quantum properties of atoms in microgravity, achieving temperatures of 100 nano-Kelvin, which is colder than interstellar space.
In 2017, physicists provided a mathematical proof concerning the third law of thermodynamics, asserting that absolute zero (0 Kelvin) cannot be physically reached. This stems from the impossibility of reducing a system's disorder (entropy) to zero. Essentially, it would require infinite steps and a limitless reservoir to dissipate heat, as any object would continually absorb heat from its environment due to the second law of thermodynamics.
When helium is cooled to 4 Kelvin, it transitions into a liquid state; further cooling it to 2.17 Kelvin allows it to exhibit superfluid properties. A superfluid is a state of matter that flows without viscosity, enabling it to seemingly defy gravity and surface tension. Liquid helium is crucial in applications such as superconducting magnets, silicon wafer production, arc welding, and cryogenics.
The United States is responsible for 75% of the world's helium supply, with 30% stored in the U.S. Federal Helium Reserve near Amarillo, Texas, which is a prime helium production area, mainly derived as a byproduct of natural gas extraction.
Liquid oxygen, while not as cold as liquid helium, is still extremely frigid, freezing at 54.36 Kelvin. It renders materials brittle upon contact and acts as a strong oxidizer, facilitating rapid combustion of organic materials in its presence. Liquid oxygen is widely utilized in space missions as a propellant and in medical applications.
Liquid nitrogen boils at 77 Kelvin and is commonly encountered in various applications, including cryotherapy and fire prevention systems.
For context, the coldest recorded temperature on Earth was at Vostok Station in Antarctica on July 21, 1983, at -128.6 degrees Fahrenheit (-89.2 degrees Celsius or 184 Kelvin). Although satellites have detected slightly colder temperatures in Antarctica, these are likely below the ice.
In the first video, "The Coldest Place in the Universe," viewers will explore the extreme temperatures of the universe and the scientific breakthroughs achieved in creating the coldest matter known.
The second video, "Science Fun Facts: The Coldest Place in the Universe is... on Earth?! ❄️🌡️ #facts #funfacts," presents intriguing facts about these astonishingly low temperatures and their implications for science.