The Pope is watching. This job is better.
Perhaps this type of idea came to the mind of Guglielmo Marconi (1874-1937) in 1932, when he installed a special antenna in the Vatican Gardens, under the eyes of Pope Pius XII (1857-1939).
This antenna was part of a new radio link, linking the Vatican to the Pope’s summer residence at Castel Gandolfo in Italy.
But it wasn’t just any radio link. It was a microwave link – very high frequency radio waves.
Marconi also installed a portable microwave communications system attached to the car to connect the Pope to the Vatican while he travelled. There are those who claim it was the first mobile phone, but it certainly wasn’t portable at all.
Thirteen years earlier, Marconi had been awarded the Nobel Prize in Physics, jointly with Karl Ferdinand Braun (1850-1918), for his contributions to wireless telegraphy.
The radio era was in full swing. But with microwaves, Marconi began to use a part of the radio wave spectrum that has very special properties.
Microwaves can transmit huge amounts of information. They can also cook food or interfere with enemy electronic devices. Microwaves even help reveal the origins of the universe.
Beep beep beep
Long before Marconi built a microwave phone for the Pope, someone else was experimenting with similar frequencies.
In the late 19th century, a brilliant Indian scientist named Jagadish Chandra Bose (1858-1937) — now largely forgotten, unfortunately — developed some of the world’s first microwave technologies.
These technologies included the first equipment to generate millimeter waves, the same ones used today by 5G devices. Bose showed in 1895 that millimeter waves could trigger an audio signal and even fire gunfire at a distance.
Marconi certainly owed part of his leadership role to Boz.
On December 12, 1901, using a frequency outside the microwave range, the Italian inventor conducted the first transatlantic radio transmission.
Sitting in a hut on a cliff in Newfoundland, Canada, he listened for several hours to a turbulent deluge of noise in his headphones, until what he expected came: beep beep beep, the letter “S” in Morse code.
Angrily, he handed the headphone to his colleague and asked him: Can you hear anything? He listened.
It was an incredible achievement. These radio waves traveled more than 2,000 miles from southern England across the open sea. At that time, his record for long-distance radio transmission was only 129 kilometers.
Since then, some have questioned whether the transfer actually occurred as Marconi described it. But recent research shows that this feat was possible, in theory, even with his primitive equipment.
The device was called a coherer, a simple radio signal detector. Records are somewhat vague, but it’s clear that the Marconi knit was designed by none other than Bose.
“He created wonderful instruments,” according to Bose biographer Sudipto Das. But perhaps Bose was too ahead of his time.
For one thing, there were few useful applications for microwaves in the early 1900s that were not already served by low-frequency radio waves.
Bose turned away from physics to devote himself to his greatest interest, plant physiology. As a result, he “almost disappeared into oblivion,” according to Das.
Magnetic popcorn
But World War II (1939-1945) made microwaves gain importance again.
Radar allowed the military to detect enemy aircraft by reflecting radio signals. The microwave device called the magnetron, developed in the United Kingdom in 1940, turned out to be one of the most powerful and effective radar technologies in the world.
Its remarkable range and accuracy, combined with its small size suitable for installation on aircraft, gave the allied powers an important advantage that helped them win the war.
It was also the microwave-emitting magnetron that inspired engineer Percy Spencer (1894-1970), of the Raytheon Company, to invent the microwave oven in 1945.
A peanut in his pocket began to melt as he walked past the magnetrons in the laboratory. Later, a box of popcorn began flying “all over the lab,” recalls a Reader’s Digest report.
This happened because at certain frequencies, microwaves excite molecules inside the food, causing them to vibrate at the same frequency. The resulting friction causes objects to heat up.
For microwaves, the specified frequency is 2.4 GHz, which is the same frequency used by many Wi-Fi routers.
But of course, routers emit their signals at much lower power levels than microwaves – which is why we can’t make popcorn just by browsing the web.
Choosing the right frequency for cooking is very important, according to Caroline Ross, from the Massachusetts Institute of Technology (MIT) in the US.
2.4 GHz microwaves penetrate food well, and this frequency also allows the radiation to be homogeneously absorbed by food particles.
“If you increase, for example, tens of gigahertz, the penetration depth is very small,” she explains. “So almost everything gets in the way, even water in the air.”
Microwave devices are special, in part, because of their ability to interact with matter at specific frequencies.
It’s true that heating up leftover dinner may not sound very exciting. But what about using microwaves to trigger noise in people’s heads?
Havana syndrome
Soldiers who worked near large microwave radar installations built during World War II later reported feeling the radar in operation.
“You could hear the radar frequency when you stood close to the antenna,” one witness wrote in the 1950s.
Professor Emeritus James Lin, from the University of Illinois at Chicago in the US, heard these stories and tried to reproduce the effect in his laboratory in the 1970s.
“I basically used myself as a guinea pig,” he recalls, describing how he set up the microwave antenna and pointed it directly at his head.
Lin suggested that the microwaves caused pressure waves inside his head, which he took to be sound. To avoid cooking his brain, he kept his energy levels low.
“I could hear the pulse,” he says. “Since I’m still alive… I guess it wasn’t so bad.”
This phenomenon has become known as the microwave hearing effect and helps explain many of the mysterious illnesses reported by diplomats around the world. The most famous case occurred in the Cuban capital, Havana.
Victims of so-called Havana Syndrome report hearing strange discordant sounds, increased pressure in the ears, dizziness, nausea, and memory loss.
Could the enemy direct a microwave beam toward these people?
Some have rejected this hypothesis, but Lin says it remains the most plausible explanation for auditory symptoms.
There are already microwave weapons, but those that are discussed publicly tend to affect machines, not people.
The US military possesses missiles capable of destroying enemy electronic circuits with microwave waves, for example. Microwaves can also shoot down drones.
On the other hand, Lin developed ways to use microwaves in medicine, for example, to treat muscle diseases and arrhythmias.
In this case, he claims it is possible to insert a small microwave-emitting device into the heart, through a catheter, to destroy abnormal heart tissue. This technique is now widely used, and is less invasive than open-heart surgery.
“You simply send a high-energy pulse, or microwave, to burn the tissue,” he explains.
The universe speaks
In addition to saving lives, microwaves also help reveal the origins of the universe.
In the 1960s, radio astronomers Arno Penzias (1933-2024) and Robert Woodrow Wilson attempted to use a large horn antenna as a radio telescope in the US state of New Jersey. But they will only hear an annoying hiss or static.
At first, they thought it was caused by pigeon droppings on the antenna. So they scared away the birds and cleaned up the mess.
But it wasn’t the bathroom’s fault. Penzias and Wilson were listening to the voice of the universe itself.
“It’s a picture of antiquity,” says Sean McGee, of the University of Birmingham in the UK.
Penzias and Wilson discovered what we today call the cosmic microwave background radiation, a signature left by the Big Bang, the big bang that gave rise to the universe, about 13.8 billion years ago.
This work earned Penzias and Wilson half of the 1978 Nobel Prize in Physics, which they shared with Pyotr Leonidovich Kapitsa (1894–1984), for their fundamental inventions and discoveries in the field of low-temperature physics.
The residual radiation discovered by Penzias and Wilson exists throughout the universe and is responsible for a small portion of the static electricity on analog television screens.
In other words, until the advent of LED televisions, people listened to The Leftovers from the Big Bang in their living rooms.
Satellites have helped astronomers map the cosmic microwave background. Its fluctuations are recorded as slight temperature differences.
These fluctuations appear to have affected where galaxies formed during the expansion of the universe.
“We are all the result of quantum fluctuations in the early universe, which planted the seeds for galaxies,” McGee explains.
Nowadays, people use microwaves for all international satellite phone calls. This undoubtedly represents a huge leap forward compared to the equipment that Marconi installed on a car for Pope Pius XI in the 1930s.
It is quite appropriate for people to use microwaves to talk to each other in their daily lives. After all, this is how the universe speaks to us, helping confirm our understanding of the greatest story of all: how it all began.
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