Scientists Confirmed Existence Of "Second Sound"

In the world of average, everyday materials, heat tends to spread out from a localized source. Drop a burning coal into a pot of water, and that liquid will slowly rise in temperature before its heat eventually dissipates. But the world is full of rare, exotic materials that don’t exactly play by these thermal rules.

Instead of spreading out as one would expect, these superfluid quantum gasses "slosh" heat side to side — it essentially propagates as a wave. Scientists call this behavior a material’s "second sound" (the first being ordinary sound via a density wave).

Although this phenomenon has been observed before, it’s never been imaged. But recently, scientists at the Massachusetts Institute of Technology (MIT) were finally able to capture this movement of pure heat by developing a new method of thermography (a.k.a. heat-mapping).

The results of this study were published in the journal Science, and in an university press release highlighting the achievement, MIT assistant professor and co-author Richard Fletcher continued the boiling pot analogy to describe the inherent strangeness of "second sound" in these exotic superfluids.

"It’s as if you had a tank of water and made one half nearly boiling," Fletcher said. "If you then watched, the water itself might look totally calm, but suddenly the other side is hot, and then the other side is hot, and the heat goes back and forth, while the water looks totally still."

These superfluids are created when a cloud of atoms is subjected to ultra-cold temperatures approaching absolute zero (−459.67 °F). In this rare state, atoms behave differently, as they create an essentially friction-free fluid. It’s in this frictionless state that heat has been theorized to propagate like a wave.

"Second sound is the hallmark of superfluidity, but in ultracold gases so far you could only see it in this faint reflection of the density ripples that go along with it," lead author Martin Zwierlein said in a press statement. "The character of the heat wave could not be proven before."

To finally capture this second sound in action, Zweierlein and his team had to think outside the usual thermal box, as there’s a big problem trying to track heat of an ultracold object—it doesn’t emit the usual infrared radiation. So, MIT scientists designed a way to leverage radio frequencies to track certain subatomic particles known as "lithium-6 fermions," which can be captured via different frequencies in relation to their temperature (i.e. warmer temperatures mean higher frequencies, and vice versa). This novel technique allowed the researchers to essentially zero in on the “hotter” frequencies (which were still very much cold) and track the resulting second wave over time.

This might feel like a big "so what?"pl After all, when’s the last time you had a close encounter with a superfluid quantum gas? But ask a materials scientist or astronomer, and you’ll get an entirely different answer.

While exotic superfluids may not fill up our lives (yet), understanding the properties of second wave movement could help questions regarding high-temperature superconductors (again, still at very low temperatures) or the messy physics that lie at the heart of neutron stars.

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These American Soldiers Are Revered In China

During World War II, some American engineers were given a one-year contract to live and work in China, flying, repairing and making airplanes. Pay is as much as US$ 16,725 a month with 30 days off a year. Housing is included, and you’ll get an extra $700 a month for food. And there’s an extra $11,000 for every Japanese airplane you destroy – no limit.

That’s the deal – in inflation-adjusted 2025 dollars – that a few hundred Americans took in 1941 to become the heroes, and some would even say the saviors, of China.

Those American pilots, mechanics and support personnel became members of the American Volunteer Group (AVG), later known as the Flying Tigers.

The group’s warplanes featured the gaping, tooth-filled mouth of a shark on their nose, a fearsome symbol still used by some US military aircraft to this day.

The symbolic fierceness was backed up by AVG pilots in combat. The Flying Tigers are credited with destroying as many as 497 Japanese planes while losing only 73.

Today, despite US-China tensions, those American mercenaries are still revered in China.

"China always remembers the contribution and sacrifice made to it by the United States and the American people during the World War II," says an entry on the Flying Tigers memorial page of China’s state-run newspaper People’s Daily Online.

The bond is such that the daughter and granddaughter of the Flying Tigers’ founder are among the few Americans invited to Wednesday’s military parade in Beijing commemorating the end of World War II.

In the late 1930s, China had been invaded by the armies of Imperial Japan and was struggling to withstand its better equipped and unified foe. Japan was virtually unopposed in the air, able to bomb Chinese cities at will.

Leader Chiang Kai-shek, who had been able to loosely unite China’s warlords under a central government, later hired American Claire Chennault, a retired US Army captain, to form an air force.

Chennault first spent a few years putting together an air raid warning network and building airbases across China, according to the Flying Tigers’ official website. In 1940, he was dispatched to the United States – still a neutral party – to find pilots and planes that could defend China against Japan.

With good contacts in the administration of US President Franklin Roosevelt and a budget that could pay Americans as much as three times what they could earn in the US military, Chennault was able to get the fliers he needed.

A deal was secured to get 100 Curtiss P-40B fighters built for Britain sent to China instead.

In his memoirs, Chennault wrote that the P-40s he got lacked a modern gun sight.

His pilots were "aiming their guns through a crude, homemade, ring-and-post gun sight instead of the more accurate optical sights used by the Air Corps and the Royal Air Force," he wrote.

What the P-40 lacked in ability, Chennault made up for in tactics, having the AVG pilots dive from a high position and unleash their heavy machine guns on the structurally weaker but more maneuverable Japanese planes.

In a low, twisting, turning dogfight, the P-40 would lose.

The pilots Chennault enrolled were far from the cream of the crop.

Ninety-nine fliers, along with support personnel, made the trip to China in the fall of 1941, according to the US Defense Department history.

Some were fresh out of flight school, others flew lumbering flying boats or were ferry pilots for large bombers. They signed up for the Far East adventure to make a lot of money or because they were simply bored.

Perhaps the best known of the Flying Tigers, US Marine Greg Boyington – around whom the 1970’s TV show "Black Sheep Squadron" was based – was in it for the money.

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A New Synthetic Lifeform That Could Spell Doom For Humankind

It's a technology that doesn't even exist yet, but its effects could be so drastically destructive that scientists in the field are calling for it to be banned now, before it's too late.

We're talking, of course, about "mirror life" — synthetic organisms that quite literally turn natural biology on its head.

"We should choose not to build mirror life and pass laws to ensure nobody can," John Glass, a synthetic biologist who helped create the first living cell with a synthetic genome, wrote in a speculative yet terrifying piece for the Financial Times. "The question is not whether we are able to prevent this threat — it is whether we will act while we still can."

Mirror lifeforms contain DNA structures that are the mirror image to all known organisms. In all life on Earth, the DNA double helix is right-handed, meaning its strands, a sugar-phosphate backbone, twist to the right. (If you make a thumbs-up with your right hand, the vertical axis would be aligned with your thumb, while your fingers represent the curl of the spiral.) The opposite is the case for proteins, the building blocks of cells, which are left-handed.

This so-called homochirality is true for all known lifeforms. So what happens when humans engineer a synthetic organism where its DNA twists to the left, while its proteins twist to the right?

The scary thing is that we can't say for sure — but many biologists fear the worst. In December, a group of leading figures in the field, including two Nobel laureates, published a massive technical report warning that the consequences of mirror life "could be globally disastrous," possibly even wiping out all life if the new organisms prove pathogenic to existing life, like us humans.

In June of this year, more than 150 scientists and ethicists echoed these concerns in a conference at the Institut Pasteur in Paris to weigh the risks of developing the tech. "It was something I never expected to see in my scientific career," Glass wrote. He noted that the Alfred P Sloan Foundation, an influential nonprofit organization that funds scientific research, has been unequivocal that it will not support efforts to create mirror organisms.

Most scientists agree that the technology is at least a decade away, perhaps three. But their sense of urgency in preventing it is palpable.

"Once it is possible to build a mirror cell, it would be comparatively easy to engineer many more kinds of mirror bacteria — the simplest form of mirror life," Glass wrote. "If this is achieved and Pandora's box opens it could pose extraordinary risks."

"To the best of our knowledge, our immune systems produce very weak antibody responses against mirror molecules, if any," he explained. "Having even one immune deficiency can cause a patient to die of overwhelming bacterial infections; a mirror bacterial infection might be like having many immune deficiencies at once."

Moreover, mirror bacteria could resist predation by organisms that normally keep their population in check, allowing them to run rampant across ecosystems.

"Contaminated areas could become irreversibly uninhabitable, compromising our agriculture and natural world," Glass said. "Huge numbers of people, animals and plants could be wiped out, with some driven to extinction."

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