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Over the last 150 years, researchers have devised a range of techniques to achieve extremely low temperatures. Substances such as liquid nitrogen and liquid helium, both with incredibly low boiling points, have found applications in various industries. In recent years, laser cooling methods have also been introduced.
These innovative methods have led to a wide array of groundbreaking discoveries and technologies. From floating magnetic trains and super-smooth experimental ice cream to cutting-edge medical imaging equipment, lunar cold storage traps, and much more, ultra-low temperatures are proving crucial for the next wave of scientific advancements.
10. Superconductors and Magnetic-Levitating Trains
In 1911, while experimenting with extreme cooling methods, Dutch physicist Heike Kamerlingh Onnes made an extraordinary discovery about how certain materials conduct electricity. He found that simple substances like mercury can conduct electricity with no resistance once temperatures drop below a certain point.
At these extremely low temperatures, these materials become flawless conductors of electricity—thus the term 'superconductors.' In a loop made of superconducting material, an electrical current can travel indefinitely without losing any energy.
Superconductors become even more fascinating when placed atop a powerful magnet. The intense magnetic field induces an internal magnetic force within the superconductor, which then pushes away the magnet beneath. This magnetic push results in the superconductor defying gravity, floating like a tiny hoverboard.
In Japan, engineers have designed a railway system based on this very principle. SC Maglev trains—short for 'superconducting magnetic levitation'—use superconducting magnets instead of traditional wheels. These trains are cooled with liquid helium tanks and levitate 10 centimeters (4 inches) above a magnetic track. In April 2015, the L0 Series SC Maglev broke a world record for rail speed, reaching 603 kilometers per hour (375 mph) on a test track near Mount Fuji.
At present, all known superconductors only function at extremely low temperatures, which limits their applications. Even advanced superconducting materials like yttrium barium copper oxide lose their superconductivity when temperatures rise above -173 degrees Celsius (-279 °F). The ongoing challenge for scientists is to develop a way to maintain these superconducting properties at room temperature.
9. Magnetic Resonance Imaging
Liquid helium plays an essential role in the functioning of magnetic resonance imaging (MRI) scanners—the non-invasive imaging tool that enables doctors to look inside patients’ bodies. The metal wire coils inside the scanner are repeatedly immersed in the ultra-cold liquid to reduce their electrical resistance. These coils generate a magnetic field that is up to 40,000 times stronger than the Earth's magnetic field.
However, there is a significant issue with this setup: We're running out of helium. Helium is in dangerously short supply, with no known method to produce more. A single MRI scanner needs 1,700 liters (449 gallons) of liquid helium to cool the magnetic coils to an astonishing -269 degrees Celsius (-452 °F).
8. Bose-Einstein Condensates
Low temperatures can lead to some truly unusual behavior in gases. Normally, the atoms in a gas are in constant motion—speeding around, bouncing off the container's walls, and colliding with each other. If the gas is heated, the movement of the atoms becomes even more vigorous and chaotic.
However, when certain gases are cooled to extreme temperatures—around -273 degrees Celsius (-460 °F)—the individual atoms begin to lose energy dramatically. Eventually, when the atoms can't shed any more energy, they transform into a rare form of matter known as a Bose-Einstein condensate (BEC).
One of the most fascinating and remarkable properties of BECs is their ability to slow and even stop light. Danish physicist Lene Hau demonstrated this phenomenon by slowing a laser beam from the speed of light to approximately 17 meters per second (56 ft/sec).
Hau and her team also developed a method for storing light pulses within BECs. These groundbreaking advances could lead to new ways of storing data, especially in the realm of quantum computing.
Though Albert Einstein and Satyendra Nath Bose first proposed the concept in the 1920s, it wasn’t until 1995—nearly 70 years later—that the first BEC was created. American physicists Eric Cornell and Carl Wieman achieved this by cooling a rubidium gas to 170 nK—over a million times colder than outer space.
For their groundbreaking contribution to scientific research, the duo—along with MIT professor Wolfgang Ketterle—were awarded the Nobel Prize in Physics in 2001.
7. Cryotherapy
Cryotherapy is a broad term used to describe the application of extremely low temperatures for medical purposes. Typically, subzero chemicals are applied through a specialized cryoprobe to remove abnormal tissue cells. This can range from freezing off a bothersome wart to targeting and destroying cancerous tumors.
Some advocates of cryotherapy argue that it has many other extraordinary benefits. They suggest that immersing yourself in a chamber colder than -100 degrees Celsius (-148 °F) can stave off dementia, alleviate depression, and even assist in weight loss. However, the scientific evidence supporting these claims is questionable.
6. Craters on the Moon
The coldest-known location in our solar system is surprisingly closer to Earth than you might think. Initially, it was believed to be the surface of Pluto. However, in 2009, scientists discovered craters near the Moon's south pole that can reach temperatures as low as -248 degrees Celsius (-414 °F) during winter. This breakthrough came from NASA’s Lunar Reconnaissance Orbiter, which measured radiation levels from 50 kilometers (31 miles) above the Moon’s surface.
The lowest temperatures are found within lunar crevices that remain in permanent shadow, never receiving any sunlight. These subzero craters act as 'cold traps,' gathering elements and volatile gases that provide valuable insights into the Moon’s history. For example, minerals found in Cabeus—a 98-kilometer (61 miles) wide crater near the south pole—point to a history of comet impacts.
However, the surface of the Moon isn't always freezing. In fact, temperatures vary greatly depending on the time and location. At the equator around midday, the heat is so intense it could boil water, while the poles can reach near-liquid oxygen temperatures during the night.
5. Liquid Nitrogen Ice Cream
Traditional ice cream is made using specialized freezers that blend milk, cream, and sugar into a smooth, delicious treat. But some producers like to take a different approach. By incorporating ultracold chemicals, they’ve been able to speed up the production process. Ice cream usually takes time to freeze, but using liquid nitrogen, manufacturers can quickly churn out batch after batch in just a few minutes.
A major challenge for ice cream makers is to freeze the mixture as quickly as possible. When freezing happens slowly, large, rough ice crystals form. While fascinating under a microscope, they negatively affect the texture of the ice cream.
On the other hand, freezing with liquid nitrogen at rapid speeds results in much smaller crystals. This creates the smooth, creamy consistency that makes the ice cream truly irresistible.
This visually stunning process has gained massive popularity in trendy ice cream parlors and among avant-garde chefs. The ice cream is made in clouds of mist, giving customers a unique, fashionable experience. One parlor in Brooklyn even adds liquid nitrogen to its hot chocolate for a little extra drama.
4. Liquid Nitrogen Cocktails
While we’ve already touched on the rise of liquid nitrogen ice cream, the culinary world isn’t stopping there. This incredibly cold substance, at -196 degrees Celsius (-320 °F), is being used in various other innovative ways: from cryo-blanching vegetables to grinding frozen herbs, breaking berries into tiny icy droplets, and much more.
Some bartenders have embraced the trend as well, incorporating liquid nitrogen into their drinks for a mesmerizing effect. Liquid nitrogen cocktails create a smoky mist that swirls above the glass, resembling a magical potion. These drinks have become a hit as a fun and unique experience for patrons.
However, these trendy drinks do carry certain risks.
In 2012, a British woman required surgery to remove part of her stomach after consuming one of these hazardous beverages. Eighteen-year-old Gaby Scanlon needed a gastrectomy after a night out at Oscars bar in Lancaster, where she accidentally caused severe frostbite to her internal organs with a liquid nitrogen cocktail.
The cryogenic cocktails faced severe criticism following the incident. The British Compressed Gases Association condemned the practice, calling it an “extremely stupid” thing to do.
3. Absolute Zero
When it comes to the coldest temperatures explored on this list, absolute zero stands as the ultimate extreme. In fact, it represents the lowest possible temperature in theory—there is no temperature colder. At absolute zero, particles in a gas would have almost no energy, and their movement would be restricted to tiny fluctuations dictated by quantum physics.
Absolute zero is so extraordinary that in 1954, scientists introduced an entirely new temperature scale to measure it. They named it the Kelvin (K) scale, after the Irish physicist Lord Kelvin.
As implied by the name, absolute zero corresponds to 0 Kelvin (0 K), which equates to -273.15 degrees Celsius (-459.67 °F). We've already covered temperatures just slightly above 0 K in our discussion of Bose-Einstein condensates.
It's important to note, however, that absolute zero is a purely theoretical concept. According to the Third Law of Thermodynamics, achieving this temperature would require an infinite amount of energy.
Nevertheless, scientists using laser cooling methods have come astonishingly close. In 2015, researchers at Stanford University succeeded in cooling a cloud of rubidium atoms to just 50 trillionths of a degree above 0 K, setting the record for the lowest temperature ever recorded.
As these advanced cooling techniques continue to improve, we can expect even more exciting developments in temperature-based research. Liquid nitrogen was once a cutting-edge discovery at the beginning of the 20th century, and now we have the ability to experiment at temperatures that approach absolute zero. What the next century will bring, however, remains to be seen.
2. Serious Injuries
While certain animals can endure freezing temperatures for extended periods, most humans find such extreme cold to be highly dangerous. You may think that the worst thing a quick blast of severe cold can do is freeze your tongue to a lamppost. However, at these extremes, even a brief exposure can cause permanent harm. For instance, liquid nitrogen can freeze your skin or eye fluid, which may lead to frostbite, eye injury, or even more severe consequences.
In fact, a particularly foolish use of liquid nitrogen resulted in a man falling into a coma. During the summer of 2013, energy drink company Jagermeister hosted a promotional pool party in Leon, Mexico. To enhance the atmosphere, the organizers decided to create a mist hovering over the pool.
When liquid nitrogen vaporizes, it generates a stunning nitrogen fog. So, rather than utilizing fog machines, the organizers opted to pour massive amounts of liquid nitrogen into the pool.
The consequences were catastrophic.
While the cryogenic chemicals certainly generated a considerable amount of fog, they also led to the hospitalization of nine people. Instead of inhaling oxygen, swimmers began breathing in the nitrogen fog that enveloped the pool and started to suffocate.
Paramedics had to rescue individuals after several swimmers lost consciousness, including a 21-year-old man who slipped into a coma. Thankfully, all those injured at the party eventually made a full recovery.
1. The Survival of Tough Animals
When faced with extremely cold environments, most known creatures would struggle to survive, especially warm-blooded mammals. For humans, hypothermia sets in when our core temperature drops below 35 degrees Celsius (95 °F). This causes our heart and internal organs to malfunction, and prolonged exposure can lead them to shut down completely.
There are a few remarkable little creatures capable of surviving extreme temperatures that would be unthinkable for us humans. Among them is the tiny parasitic leech from East Asia, known as Ozobranchus jantseanus. Japanese researchers have found that these leeches can endure temperatures as low as -196 degrees Celsius (-320 °F) for up to 24 hours.
Only two other species have managed to endure such low temperatures—water bears and drosophilid fly larvae. However, both could only last for an hour in those conditions.
In an even more astonishing feat, an entire group of these leeches survived nine months stored at -90 degrees Celsius (-130 °F), just a few degrees above the coldest temperature ever recorded on Earth. Some of the leeches even thrived for 2.5 years.
Scientists are still baffled as to why this East Asian leech has such an extraordinary tolerance to extreme cold, especially considering it would never normally encounter such freezing conditions in its natural habitat. If researchers can uncover the secret, it could lead to advancements in cryopreservation techniques.
