Archive for the ‘history of science’ Category

Scientists found that these old photographs contain metallic nanoparticles

June 12th, 2019
The earliest reliably dated photograph of people, taken by Louis Daguerre one spring morning in 1838.

Enlarge / The earliest reliably dated photograph of people, taken by Louis Daguerre one spring morning in 1838. (credit: Public domain)

Daguerreotypes are one of the earliest forms of photography, producing images on silver plates that look subtly different, depending on viewing angle. For instance they can appear positive or negative, or the colors can shift from bluish to brownish-red tones. Now an interdisciplinary team of scientists has discovered that these unusual optical effects are due to the presence of metallic nanoparticles in the plates. They described their findings in a new paper in the Proceedings of the National Academy of Sciences.

Co-author Alejandro Manjavacas—now at the University of New Mexico in Albuquerque—was a postdoc at Rice University, which boasts one of the top nanophotonics research groups in the US. That's where he met his co-author, Andrea Schlather, who ended up in the scientific research department at the Metropolitan Museum of New York. The Met has a valuable collection of daguerreotypes, and her new colleagues were keen to find better methods for preserving these valuable artifacts.

Schlather contacted Manjavacas and suggested this might be a great place to apply their combined expertise in nanoplasmonics—a field dedicated to detailing how nanoparticles interact with light. Think of it this way: light is an optical oscillation made up of photons. Sound is a mechanical oscillation made up of quasiparticles known as phonons. And plasma (ionized gas, the fourth fundamental state of matter) oscillations consist of plasmons. Surface plasmons play a critical role in determining the optical properties of metals in particular.

Read 14 remaining paragraphs | Comments

Posted in History, history of science, nanoparticles, optics, photography, Physics, plasmonics, science | Comments (0)

A tale of lost WW2 uranium cubes shows why Germany’s nuclear program failed

June 3rd, 2019
This is one of the 664 uranium cubes from the failed nuclear reactor that German scientists tried to build in Haigerloch during World War II.

Enlarge / This is one of the 664 uranium cubes from the failed nuclear reactor that German scientists tried to build in Haigerloch during World War II. (credit: John T. Consoli/University of Maryland)

When University of Maryland physicist Timothy Koeth received a mysterious heavy metal cube from a friend as a birthday gift several years ago, he instantly recognized it as one of the uranium cubes used by German scientists during World War II in their unsuccessful attempt to build a working nuclear reactor. Had there been any doubt, there was an accompanying note on a piece of paper wrapped around the cube: "Taken from Germany, from the nuclear reactor Hitler tried to build. Gift of Ninninger."

Thus began Koeth's six-year quest to track down the cube's origins, as well as several other similar cubes that had somehow found their way across the Atlantic. Koeth and his partner in the quest, graduate student Miriam "Mimi" Hiebert, reported on their progress to date in the May issue of Physics Today. It's quite the tale, replete with top-secret scientific intrigue, a secret Allied mission, and even black market dealers keen to hold the US hostage over uranium cubes in their possession. Small wonder Hollywood has expressed interest in adapting the story for the screen.

Until quite recently, Koeth ran the nuclear reactor program at UMD, which is how he met his co-author. Hiebert is completing a PhD in materials science and engineering, specializing in the study of historical materials in museum collections (glass in particular) and the methods used to preserve them, using the reactor facility for neutron imaging of a few samples. Koeth told her about his research into his cube's origins, and she started collaborating with him as a side project.

Read 13 remaining paragraphs | Comments

Posted in History, history of science, Nuclear Reactor, Physics, science, World War II | Comments (0)

The soldier who removed his own bladder stone, and other medical history marvels

March 24th, 2019
A patient receiving dental treatment, circa 1892. There were several cases of "exploding teeth" in the 19th century that remain unexplained to this day.

Enlarge / A patient receiving dental treatment, circa 1892. There were several cases of "exploding teeth" in the 19th century that remain unexplained to this day. (credit: Oxford Science Archive/Getty Images)

While researching his 2017 book on the history of heart surgery, medical journalist Thomas Morris perused hundreds of journals from the 19th century. One day, a headline on the page opposite the one he was reading caught his eye: "sudden protrusion of the whole of the intestines into the scrotum." It was a bizarre case from the 1820s, involving a laborer run over by a brick-laden cart. The resulting hernia forced his intestines into his scrotum, and yet the laborer made a full recovery.

Once he got over his initial amused revulsion, Morris was struck by the sheer ingenuity displayed by doctors in treating the man's condition. And he found plenty of other similar bizarre cases as he continued his research, with people surviving truly horrifying injuries—a testament to the resiliency of the human body. "Doctors, even when they had less than a tenth of the knowledge we do today in terms of treating major trauma, could still come up with innovative and ingenious solutions to acute problems," he said.

Many of the most interesting medical cases Morris uncovered are featured in his hugely entertaining compendium of medical oddities, The Mystery of the Exploding Teeth, and Other Curiosities From the History of Medicine. Regular readers of his blog (tagline: "making you grateful for modern medicine") will revel in stories about a sword-swallowing sailor, a soldier who removed his own bladder stone, a man with combustible belches, a woman who peed through her nose, and a boy who inhaled a bird's larynx and started honking like a goose. All are delivered in elegant prose, punctuated with the author's distinctive dry wit. Morris has collected 500 or so of these frequently jaw-dropping cases thus far, and only included 70 or so in the book. So a sequel (or two) isn't out of the question

Read 8 remaining paragraphs | Comments

Posted in books, Gaming & Culture, History, history of science, medicine, science | Comments (0)

This medieval astrolabe is officially world’s oldest known such instrument

March 17th, 2019
Left: A laser imaging scan of the so-called Sodre astrolabe, recovered from the wreck of a Portuguese Armada ship. Right: The astrolabe is believed to have beeb made between 1496 and 1501.

Enlarge / Left: A laser imaging scan of the so-called Sodre astrolabe, recovered from the wreck of a Portuguese Armada ship. Right: The astrolabe is believed to have beeb made between 1496 and 1501. (credit: David Mearns/University of Warwick)

A mariner's astrolabe recovered from the wreck of one of Portuguese explorer Vasco da Gama's ships is now officially the oldest known such artifact, according to a new paper in the International Journal of Nautical Archaeology. It's even going into the Guinness Book of world records, along with the ship's bell, now that both have been independently verified as the oldest of their kind in the world.

Key distinction: this is the oldest known mariner's astrolabe. Astrolabes are actually very ancient instruments—possibly dating as far back as the Second Century, B.C.—for determining the time and position of the stars in the sky by measuring a celestial body's altitude above the horizon. They were mostly used for astronomical studies,  although they also proved useful for navigation on land. Navigating at sea was a bit more problematic, unless the waters were calm.

The development of a mariner's astrolabe—a simple ring marked in degrees for measuring celestial altitudes—helped solve that problem. It was eventually replaced by the invention of the sextant in the18th century, which was much more precise for seafaring navigation. Mariner's astrolabes are among the most prized artifacts recovered from shipwrecks; only 108 are currently catalogued worldwide.

Read 5 remaining paragraphs | Comments

Posted in astrolabes, astronomy, history of science, navigation, science, shipwrecks | Comments (0)

Quantum physicists in the 1920s helped found field of quantum biology

January 6th, 2019
There is some evidence that quantum effects might play a role in the process of photosynthesis.

Enlarge / There is some evidence that quantum effects might play a role in the process of photosynthesis. (credit: Mikel Bilbao/VW Pic/Getty Images)

In 1944, quantum physicist Erwin Schroedinger wrote a short book called What is Life: The Physical Aspect of the Living Cell, exploring how the relatively new field of quantum mechanics might play a role in biological processes. It is considered by many to be one of the earliest forays into "quantum biology," a rarefied field that attempts to apply quantum principles to living systems. But the field actually dates back to the earliest days of quantum mechanics in the 1920s, according to a recent paper published in the Proceedings of the Royal Society A.

"Quantum biology is wrongly regarded as a very new scientific discipline, when it actually began before the Second World War," said co-author Johnjoe McFadden, a microbiologist at the University of Surrey and co-director of the Centre for Quantum Biology there, with his Surrey colleague and co-author Jim Al-Khalili. "Back then, a few quantum physicists tried to understand what was special about life itself and whether quantum mechanics might shed any light on the matter."

Frankly, quantum biology has suffered from a lack of credibility until the last decade or so, when a number of intriguing studies suggested that there might be something to the idea after all. For instance, there is growing evidence that photosynthesis relies on quantum effects to help plants turn sunlight into fuel.  Migratory birds might have an internal "quantum compass" that helps them sense Earth's magnetic fields as a means of navigation. Quantum effects might play a role in the human sense of smell, helping us distinguish between different scents.

Read 13 remaining paragraphs | Comments

Posted in 12 days of Christmas, History, history of science, Physics, quantum biology, quantum mechanics, science | Comments (0)