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Year in Review

The 10 Coolest Things Of 2021

Rebecca M. Oliver
December 23, 2021

The launch of the James Webb Space Telescope last weekend struck an appropriately high note to end the year of notable scientific achievements. We documented many of them in our science and technology column, The 5 Coolest Things On Earth This Week. Here’s a list of 10 from 2021 that stood out:


Dream Catchers

NW Univ Dream Study


What is it? Experiments at four universities found that people in rapid-eye-movement (REM) sleep, when most dreaming occurs, can interact with researchers, answer questions and even do simple math in real time.

Why does it matter? “Sleep has been defined as a state in which the brain is disconnected and unaware of the outside world,” according to Science. These studies suggest it’s possible to establish interactive sleep with more complex cognitive activity. “Almost everything that’s known about dreams has relied on retrospective reports given when the person is awake, and these can be distorted,” says Karen Konkoly, a cognitive neuroscientist at Northwestern University and lead author of the combined study, published in Current Biology. Konkoly hopes the new communication techniques could one day be used therapeutically for people experiencing trauma, anxiety and depression.

How does it work? Teams leading four separate university studies in the U.S., France, Germany and the Netherlands trained participants to recognize their dream states, along with various signals from researchers, including sound, light or finger tapping. Scientists monitored subjects’ brain activity, eye movement and facial muscles with electrode-fitted helmets as they fell asleep. When researchers asked the dreamers simple questions or calculations, they responded with the cues they’d been taught beforehand, like smiling, frowning or moving their eyes a certain number of times. Each of the studies taught different response methods; at the German lab, dreamers used eye movements to signal in Morse code. “It is proof of concept,” says Benjamin Baird, a cognitive neuroscientist who discussed the study with Science. “And the fact that different labs used all these different ways to prove it is possible to have this kind of two-way communication… makes it stronger.”


Do The Write Thing

mental handwriting

What is it? Stanford researchers found a way to “quickly convert [a person’s] thoughts about handwriting into text on a computer screen.”

Why does it matter? The technology, which involves an AI program and a brain-computer interface (BCI), could help people with paralysis or who can’t move their hands communicate with handwriting. “We’ve learned that complicated intended motions involving changing speeds and curved trajectories, like handwriting, can be interpreted more easily and more rapidly by the artificial-intelligence algorithms we’re using,” said research scientist Frank Willett, lead author of the study’s findings, which were published in the journal Nature. “Alphabetical letters are different from one another, so they’re easier to tell apart.”

How does it work? The study’s participant, a man researchers refer to as T5, was fitted with two BCI chips. The chips contained electrodes that picked up signals from the brain’s motor cortex, which controls hand movements. When T5 focused his thoughts on writing letters of the alphabet on paper with a pen, the BCI sent these signals to a computer, where the newly developed algorithm transcribed them into text on a screen. T5 repeated each letter ten times to teach the program his handwriting style. Ultimately, he set new speed records for copying sentences (around 18 words per minute) and “freestyle writing” (15 words per minute, triple the previous record from a keyboard-and-mouse setup).


Hearing Crickets

Tel Aviv crickets


What is it? Scientists at Tel Aviv University used a dead locust’s ear to give a robot a sense of hearing.

Why does it matter? Scientists believe that the inherent advantages of biological systems — finely tuned senses such as smell, sight, hearing and touch — could one day be used to build smarter electronic systems, according to the university. “Nature is much more advanced than we are, so we should use it,” says Dr. Ben M. Maoz, who co-supervised a new study that applied this approach.

How does it work? First, researchers built a robot that responds to environmental stimuli. Next, Maoz and his colleagues created what they call an “Ear-on-a-Chip,” a device that supplied oxygen and food to the locust ear and took electronic signals out. They amplified these signals and sent them to the robot. “The result is extraordinary: When the researchers clap once, the locust's ear hears the sound and the robot moves forward; when the researchers clap twice, the robot moves backwards,” the university reports. The results of the experiment were published in the journal Sensors. Maoz says the study “opens the door to sensory integrations between robots and insects—and may make much more cumbersome and expensive developments in the field of robotics redundant.”


Holograms On Demand

Holograms on demand


What is it? MIT researchers are using deep learning to produce holographic images on consumer laptops and smartphones in real time.

Why does it matter? The technology, called “tensor holography,” could help holograms jump from credit cards to fields like virtual reality, 3D printing and medical imaging.

How does it work? The team first produced typical holograms with existing, computer-based methods, which are modeled after the human eye. Then, MIT says, researchers “built a custom database of 4,000 pairs of computer-generated images” and used the resulting data to train a deep-learning model that adjusted its algorithms accordingly. The result? More realistic holograms in milliseconds. Study co-author Wojciech Matusik says: “It’s a considerable leap that could completely change people’s attitudes toward holography. We feel like neural networks were born for this task.”


Cold Comfort

Purdue white paint


What is it? Purdue University engineers have created the world’s whitest paint, with light-reflecting capabilities that can cool a building from the outside.

Why does it matter? Typical commercial white paint, like other colors, warms up in the sun. Paints designed to reflect heat bounce only 80% to 90% of sunlight and can’t cool a surface below the ambient temperature. This new paint formula reflects 98.1% of sunlight, sending infrared heat away from the painted surface. “If you were to use this paint to cover a roof area of about 1,000 square feet, we estimate that you could get a cooling power of 10 kilowatts,” said Xiulin Ruan, a Purdue professor of mechanical engineering. “That’s more powerful than the central air conditioners used by most houses.” A paper by the research team was published in ACS Applied Materials & Interfaces.

How does it work? The paint gets its extreme whiteness from barium sulfate, a chemical compound used commercially to make photo paper whiter than other standard papers. The barium sulfate particles in the paint vary in size, allowing them to scatter a broad spectrum of sunlight. The paint was shown to drop the temperature of painted surfaces by 19 degrees Fahrenheit at night and by 8 degrees during peak-sun daytime hours.


The Big Picture

quantum hard drives


What is it? Australian scientists believe a 200-year-old light experiment and quantum hard drives could help pave the way to an Earth-size telescope.

Why does it matter? What humans can see of the universe has so far been limited by the size of the telescopes we can make — specifically, their mirrors. A new approach sidesteps those hurdles and could produce incredibly detailed images of the universe.

How does it work? The idea builds on Thomas Young’s double-slit experiment from 1801, which provided evidence that light moves in waves, and quantum physics, which tells us that light is also a particle with wave-like properties. Plugging in a quantum hard drive at each of multiple telescopes would allow astronomers to record and store starlight in its wave form. Later, scientists could transport the hard drives to a single location, combine the signals and behold a remarkably detailed new window on the universe. Researchers have thought this step forward would require a highly advanced quantum internet. But a team from the University of Sydney and the Australian National University propose it can be done with hard drives that are in development today and could be used in the field in five to 10 years.


We Were Promised Flying Cars — And Now We Have Them

flying car

What is it? An R&D firm successfully took a flying car on a 35-minute flight between airports in Slovakia.

Why does it matter? It’s pretty cool, and it could be a new business. “There are about 40,000 orders of aircraft in the United States alone,” Anton Zajac, a co-founder and adviser at Klein Vision, which developed the AirCar told BBC News. “If we convert 5% of those, to change the aircraft for the flying car — we have a huge market.”

How does it work? The AirCar, which one avionics expert described as “the lovechild of a Bugatti Veyron and a Cessna 172,” uses a 160-horsepower BMW engine with regular gasoline to power a fixed propeller that sits behind the driver. The vehicle can carry two passengers and fly at a cruising speed of 118 miles per hour, at an altitude of 8,200 feet, with a range of 600 miles. It takes just over two minutes for the wings to unfold for a runway takeoff.


Seeing Is Believing

Brain organoid

What is it? German researchers developed a brain organoid with light-sensitive “optic cups” that mimic some abilities of the human eye.

Why does it matter? Researchers use human stem cells to grow organoids, miniature versions of our organs that mimic some of their basic functions. German researchers took it a step further by inducing a brain organoid to grow two symmetrical optic cups, structures with cell types and light sensitivity similar to the human eye. “These organoids can help to study brain-eye interactions during embryo development, model congenital retinal disorders, and generate patient-specific retinal cell types for personalized drug testing and transplantation therapies,” said researcher Jay Gopalakrishnan, senior author of a study on the findings published in the journal Cell Stem Cell.

How does it work? The team started with human-induced pluripotent stem cells (iPSCs), a type of universal building block that can be used to grow many cell types and structures of the human body. Gopalakrishnan and his team adjusted a protocol they had developed previously for growing brain tissue. In the organoids, optic cups appeared at 30 days and developed structurally around 50 days, the same timeframe for retinal development in a human embryo. The cups formed optical lens and retinal tissue with “electrically active neuronal networks” that responded to light similarly to natural human functional vision.


Don’t Fear The Water

water-repellent gel Florida


What is it? A research team in Florida created a “superhydrophobic,” or water-repellent, gel that can keep surfaces dry underwater for hours.

Why does it matter? Being able to repel water is more than just a convenient feature for camping gear and suede shoes. It’s important for many high-tech applications in energy and advanced electronics. “For example, the new gel makes splitting electrocatalysis easier, which could lead to more efficient fuel cells,” said Debashis Chanda, a professor at the University of Central Florida who led the research team. “The same gel can lead to better electron acceptors, which are key in developing highly sensitive detectors and sensors for toxic gasses. There is a lot of potential.”

How does it work? The team has built bundles of 60 to 70 carbon atoms each, which formed cage-like structures called fullerenes, then stacked these cages into crystal-like nanostructures called fullerites. A drop of the fullerite gel triggered “a super water-repellent state” on the treated surface, while the open-cage structure allowed the treated material to retain its original properties. “Because these superhydrophobic surfaces are created in a very facile and easy process using pure carbon fullerenes, we anticipate they can be exploited in many experiments and real-life applications,” said Rinku Saran, a postdoctoral fellow in the lab that developed the gel. The work is featured on the cover of the journal Advanced Materials.


Science Shells Out

The microstructure of a glass-acrylic composite (left) was inspired by that of seashell nacre (right), better known as mother of pearl. Image credit: McGill University.

What is it? McGill University scientists created superstrong glass inspired by mollusk shells’ tough inner layer.

Why does it matter? Advances in electronics and device screens have created demanding applications for glass, and the material is still catching up. Tough and flexible glass could open doors to devices that seem futuristic today.

How does it work? McGill bioengineering professor Allen Ehrlicher was inspired by nacre, the inner surface of mollusk shells, commonly known as mother-of-pearl, to create a more durable but still transparent glass-acrylic composite. The team examined nacre’s microstructure and mimicked it with layers of glass flakes and acrylic. This produced a cheap and very strong material, but it was opaque. “By tuning the refractive index of the acrylic, we made it seamlessly blend with the glass to make a truly transparent composite,” explained Ali Amini, lead author of the team’s study, which was published in Science. Ehrlicher added that the new material is “three times stronger than normal glass but also more than five times more fracture resistant.”