Enlarge / Scientists at the University of Nottingham have discovered how to create different colors of blue cheese. (credit: University of Nottingham)

Gourmands are well aware of the many varieties of blue cheese , known by the blue-green veins that ripple through the cheese. Different kinds of blue cheese have distinctive flavor profiles: they can be mild or strong, sweet or salty, for example. Soon we might be able to buy blue cheeses that belie the name and sport veins of different colors: perhaps yellow-green, reddish-brown-pink, or lighter/darker shades of blue, according to a recent paper published in the journal Science of Food.

“We’ve been interested in cheese fungi for over 10 years, and traditionally when you develop mould-ripened cheeses, you get blue cheeses such as Stilton , Roquefort , and Gorgonzola , which use fixed strains of fungi that are blue-green in color," said co-author Paul Dyer of the University of Nottingham of this latest research. "We wanted to see if we could develop new strains with new flavors and appearances."

Blue cheese has been around for a very long time. Legend has it that a young boy left his bread and ewe's milk cheese in a nearby cave to pursue a lovely young lady he'd spotted in the distance. Months later, he came back to the cave and found it had molded into Roquefort. It's a fanciful tale, but scholars think the basic idea is sound: people used to store cheeses in caves because their temperature and moisture levels were especially hospitable to harmless molds. That was bolstered by a 2021 analysis of paleofeces that found evidence that Iron Age salt miners in Hallstatt (Austria) between 800 and 400 BCE were already eating blue cheese and quaffing beer.

We've been following the annual Dance Your PhD contest for several years now, delighting in the many creative approaches researchers have devised to adapt their doctoral theses into movement—from "nano-sponge" materials and superconductivity to the physics of atmospheric molecular clusters and the science of COVID-19. This year's winner is Weliton Menário Costa of the Australian National University for his thesis "Personality, Social Environment, and Maternal-level Effects: Insights from a Wild Kangaroo Population." His video entry, "Kangaroo Time," is having a bit of a viral moment, charming viewers with its catchy beat and colorful, quirky mix of dance styles and personalities—both human and kangaroo.

As we reported previously , the Dance Your PhD contest was established in 2008 by science journalist John Bohannon. It was previously sponsored by Science magazine and the American Association for the Advancement of Science (AAAS) and is now sponsored by the AI company Primer, where Bohannon is the director of science. Bohannon told Slate in 2011 that he came up with the idea while trying to figure out how to get a group of stressed-out PhD students in the middle of defending their theses to let off a little steam. So he put together a dance party at Austria's Institute of Molecular Biotechnology , including a contest for whichever candidate could best explain their thesis topics with interpretive dance.

The contest was such a hit that Bohannon started getting emails asking when the next would be—and Dance Your PhD has continued ever since. It's now in its 16th year. There are four broad categories: physics, chemistry, biology, and social science, with a fairly liberal interpretation of what topics fall under each. All category winners receive $750, while Costa, as the overall champion, will receive an additional $2,000.

Enlarge / New study finds that the chemicals listed on tattoo ink labels often don't match what's actually in the bottle. (credit: ohsarahrose/CC BY-SA 2.0 )

If you live in the US and are planning on getting a tattoo any time soon, we've got some potentially unwelcome news. Many common commercial tattoo inks have either different ingredients than those listed on the label or additional substances that are not listed at all, according to a new paper published in the journal Analytical Chemistry. And there are other scientific studies suggesting that some of those ingredients could have adverse health effects, either in the form of allergic reactions or skin or other cancers.

“Our goal is to empower artists and their clients," said co-author John Swierk , a chemist at Binghamton University. "Tattoo artists are serious professionals who have dedicated their lives to this craft, and they want the best possible outcomes for their clients. We’re trying to highlight that there are some deficiencies in manufacturing and labeling.”

Typical tattoo ink contains one or more pigments (which give the ink its color) within a "carrier package" to help deliver the pigments into the skin. The pigments are the same as those used in paints and textiles. They can be either small bits of solids or discrete molecules, such as titanium dioxide or iron oxide (for white or rust-brown colors, respectively). As for the carrier packages, most ink manufacturers use grain or rubbing alcohol, sometimes with a bit of witch hazel added to the mix to help the skin heal after the tattooing process. There may also be other additives to adjust the viscosity and keep pigment particles suspended in the carrier package.

Some of the microbes that make carbon sequestration work. (credit: Andes Ag, Inc)

In 2022, humans emitted a staggering 36 gigatons of carbon dioxide into the atmosphere. Along with reducing emissions, removing carbon dioxide from the atmosphere is a key climate mitigation strategy. But Gonzalo Fuenzalida wasn’t looking to help solve climate change when he co-founded the company Andes .

“We started this company with the idea of using microbes to make the process of growing food more resilient,” says Fuenzalida. “We stumbled upon these microbes that have the ability to create minerals in the soil which contain carbon and that intrigued us.”

Fuenzalida, alongside his co-founder Tania Timmermann-Aranis, had an unconventional notion: They could harness the power of microbes residing in plant roots within the soil to remove carbon from the atmosphere. These naturally occurring microbes can be applied to the soil by blending them with pesticides or other soil treatments—they will strategically position themselves within the root structure of corn, wheat, and soy plants.

Enlarge / A red mud retaining pond in Germany. (credit: Wikimedia Commons )

The metals that form the foundation of modern society also cause a number of problems. Separating the metals we want from other minerals is often energy-intensive and can leave behind large volumes of toxic waste. Getting them in a pure form can often require a second and considerable energy input, boosting the associated carbon emissions.

A team of researchers from Germany has now figured out how to handle some of these problems for a specific class of mining waste created during aluminum production. Their method relies on hydrogen and electricity, which can both be sourced from renewable power and extracts iron and potentially other metals from the waste. What's left behind may still be toxic but isn't as environmentally damaging.

Out of the mud

The first step in aluminum production is the isolation of aluminum oxide from the other materials in the ore. This leaves behind a material known as red mud; it's estimated that nearly 200 million tonnes are produced annually. While the red color comes from the iron oxides present, there are a lot of other materials in it, some of which can be toxic. And the process of isolating the aluminum oxide leaves the material with a very basic pH.

Enlarge (credit: Assaf Peretz/Israel Antiquities Authority)

There's rarely time to write about every cool science-y story that comes our way. So this year, we're once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2020, each day from December 25 through January 5. Today: Archaeologists relied on chemical clues and techniques like FTIR spectroscopy and archaeomagnetic analysis to reconstruct the burning of Jerusalem by Babylonian forces around 586 BCE.

Archaeologists have uncovered new evidence in support of Biblical accounts of the siege and burning of the city of Jerusalem by the Babylonians around 586 BCE, according to a September paper published in the Journal of Archaeological Science.

The Hebrew bible contains the only account of this momentous event, which included the destruction of Solomon's Temple . “The Babylonian chronicles from these years were not preserved,” co-author Nitsan Shalom of Tel Aviv University in Israel told New Scientist . According to the biblical account, “There was a violent and complete destruction, the whole city was burned and it stayed completely empty, like the descriptions you see in [the Book of] Lamentations about the city deserted and in complete misery.”

Enlarge / The Royal Institution was founded in 1799 and is still located in the same historic building at 21 Albermarle Street in London. (credit: Griffindor/CC BY-SA 3.0 )

If you're a fan of science, and especially science history, no trip to London is complete without visiting the Royal Institution , browsing the extensive collection of artifacts housed in the Faraday Museum and perhaps taking in an evening lecture by one of the many esteemed scientists routinely featured—including the hugely popular annual Christmas lectures . (The lecture theater may have been overhauled to meet the needs of the 21st century but walking inside still feels a bit like stepping back through time.) So what better time than the Christmas season to offer a virtual tour of some of the highlights contained within the historic walls of 21 Albemarle Street?

The Royal Institution was founded in 1799 by a group of leading British scientists. This is where Thomas Young explored the wave theory of light (at a time when the question of whether light was a particle or wave was hotly debated ); John Tyndall conducted experiments in radiant heat; Lord Rayleigh discovered argon; James Dewar liquified hydrogen and invented the forerunner of the thermos; and father-and-son duo William Henry and William Lawrence Bragg invented x-ray crystallography.

No less than 14 Nobel laureates have conducted ground-breaking research at the Institution over the ensuing centuries, but the 19th century physicist Michael Faraday is a major focus. In fact, there is a full-sized replica of Faraday's magnetic laboratory—where he made so many of his seminal discoveries—in the original basement room where he worked, complete with an old dumbwaiter from when the room was used as a servant's hall. Its arrangement is based on an 1850s painting by one of Faraday's friends and the room is filled with objects used by Faraday over the course of his scientific career.

Enlarge / Great British Bake Off judges Paul Hollywood and Prue Leith (top) and presenters Alison Hammond and Noel Fielding. (credit: Mark Bourdillon/Love Productions/Channel 4)

The Great British Bake Off ( TGBBO )—aka The Great British Baking Show in the US and Canada—features amateur bakers competing each week in a series of baking challenges, culminating in a single winner. The recipes include all manner of deliciously decadent concoctions, including the occasional Christmas dessert. But many of the show's Christmas recipes might not be as bad for your health as one might think, according to a new paper published in the annual Christmas issue of the British Medical Journal, traditionally devoted to more light-hearted scientific papers.

TGBBO made its broadcast debut in 2010 on the BBC, and its popularity grew quickly and spread across the Atlantic. The show was inspired by the traditional baking competitions at English village fetes (see any British cozy murder mystery for reference). Now entering its 15th season, the current judges are Paul Hollywood and Prue Leith, with Noel Fielding and Alison Hammond serving as hosts/presenters, providing (occasionally off-color) commentary. Each week features a theme and three challenges: a signature bake, a technical challenge, and a show-stopper bake.

The four co-authors of the new BMJ study—Joshua Wallach of Emory University and Yale University's Anant Gautam, Reshma Ramachandran, and Joseph Ross—are avid fans of TGBBO , which they declare to be "the greatest television baking competition of all time." They are also fans of desserts in general, noting that in medieval England, the Catholic Church once issued a decree requiring Christmas pudding four weeks before Christmas. Those puddings were more stew-like, containing things like prunes, raisins, carrots, nuts, spices, grains, eggs, beef, and mutton. Hence, those puddings were arguably more "healthy" than the modern take on desserts, which contain a lot more butter and sugar in particular.