A Celestial Discovery: The Black Hole Star
In 2024, astronomers examining data from the James Webb Space Telescope identified hundreds of intriguing red dots, initially thought to be young quasars from the early universe. Among these, one particularly striking red point captured their attention. This exceptionally bright object exhibited properties unlike any known astrophysical entity. The scientific community has now classified this small red dot as a “black hole star,” named for its size comparable to a large star while emitting energy far exceeding what could be produced through nuclear fusion—energy levels akin to those of an active black hole.
This remarkable finding was detailed in a comprehensive article published in Nature. Initially, the researchers speculated that the object’s intense redness stemmed from surrounding dust. However, despite its brilliant luminosity, it vanished entirely at certain wavelengths, a phenomenon known as the “Balmer break,” typically indicative of a stellar atmosphere. What sets this discovery apart is that it represents the deepest Balmer break ever recorded. Furthermore, no metallic elements or anything beyond hydrogen and helium were detected in the spectrum.
To unravel this enigmatic combination of characteristics, the authors conducted computer simulations. They hypothesised that the red dot must be a potent energy source enveloped by a dense hydrogen cocoon. The only plausible source capable of achieving such brightness—around 100 billion times that of a typical star—would be an accreting black hole. Consequently, the team concluded that MoM-BH*-1, as they have dubbed the point, is indeed a black hole star, featuring a massive central black hole (approximately 100 solar masses) wrapped in a hydrogen envelope the size of our solar system. Astronomers anticipate that the discovery of black hole stars—two others have since been identified—will shed light on the formation of supermassive black holes shortly after the Big Bang.
Turning Plastic into Edible Cookies
Plastic pollution poses a significant environmental challenge, yet researchers are finding innovative ways to address it. A team from Southern Illinois University (SIU) has discovered a method to utilise microbes for breaking down polyethylene terephthalate (PET)—the material commonly used in beverage bottles—and transforming it into edible cookies. This novel approach is posited to be particularly beneficial for astronauts on future space missions, submarines, or colonies on the Moon or Mars. Their findings were presented at a meeting of the American Chemical Society in Chicago.
Professor Lahiru Jayakody and his colleagues at SIU found that since both plastics and food are carbon-based, food products could represent a viable market for recycling PET waste. They engineered various types of yeast to convert plastic molecules into proteins, vitamins, and flavourings. This was achieved through a patented process involving high-temperature and high-pressure water and oxygen to break down plastic bottles into tiny fragments, making them more accessible to microbes. These microbes then facilitate the transformation of the fragments into proteins, fats, and acids.
The final step involves incorporating fibre, starch, and sweeteners, followed by extruding the resulting mixture with a 3D printer to form small cookies, aptly named µBites (microbocados). While human taste tests have yet to be conducted, initial feedback from participants indicated that the cookies smell delightful, with many expressing willingness to consume them if faced with limited food options. Although this feedback may not be overwhelmingly enthusiastic, it marks a promising start. The team is actively working to enhance the cookies’ palatability, aiming for them to be ready for consumption within a few years.
The Whales’ Songs and Einstein’s Theory
It might seem surprising to think that the songs of whales could relate to Albert Einstein’s theory of special relativity, yet oceanographer John Spiesberger, a visiting researcher at the University of Pennsylvania, argues otherwise. The exploration began when Spiesberger was testing a computer programme designed to calculate the sound speed of whale songs, a crucial component of his equations for tracking these marine mammals. Whale songs can travel up to 100 kilometres underwater, allowing researchers to locate the animals by comparing the arrival times of the sounds at underwater receptors.
However, Spiesberger encountered varying sound speed readings, ranging from 1,000 to 3,000 metres per second, while the standard sound speed in seawater is approximately 1,500 metres per second. He realised that this discrepancy was not a software error but rather a physical phenomenon. When a whale is near the surface, the receptors pick up both the direct signal and its reflected echo. This phenomenon, known as temporal interference, causes the strongest part of the signal to appear to accelerate, sometimes giving the illusion of travelling faster than light. Nonetheless, the information encoded within adheres to the fundamental principles of special relativity, signifying no breach of physical laws. Following simulations that demonstrated this connection, Spiesberger is now focused on capturing the effect in real-world scenarios by deploying a series of audio microphones on a solid substrate, mirroring the acoustic properties of the ocean floor.
Understanding Mosquito Preferences
As someone who often attracts mosquitoes, I am well aware of the discomfort these tiny blood-sucking parasites can cause. Scientists have long recognised that mosquitoes are drawn to human body chemistry, but it turns out that each species has its own unique preferences for interpreting human scent, according to research published in iScience. This insight could pave the way for the development of species-specific repellents and enhance regional strategies for combating mosquito-borne diseases.
The study, led by Matthew DeGennaro at Florida International University, examined three mosquito species: the Egyptian mosquito (Aedes aegypti), the Asian tiger mosquito (Aedes albopictus), and the southern house mosquito (Culex quinquefasciatus). All three species were exposed to 119 human volunteers willing to be bitten for scientific purposes. The Egyptian mosquito, which feeds during the day, demonstrated a preference for males over females. The Asian tiger mosquito, also diurnal, was particularly attracted to elevated levels of ketones and plant-like volatile compounds. In contrast, the southern house mosquito, which feeds at night, selected hosts based on their individual microbiomes—the bacteria, fungi, and microbes residing on the skin. Some microbiomes attracted mosquitoes, while others deterred them.
Avocado Trees and Their Unique Floral Gender Roles
While enjoying a freshly made guacamole, consider this: avocado trees are hermaphroditic, meaning their flowers can either release pollen (acting as “males”) or receive it (functioning as “females”). These trees alternate between these roles throughout the day to prevent self-pollination. Approximately half of avocado trees (type A) are programmed to open their female flowers in the morning and male flowers in the afternoon, while the other half follows the opposite pattern (type B). Researchers from the University of California, Davis, have identified a genetic mechanism behind this century-old mystery, as detailed in proceedings of the National Academy of Sciences.
By analysing the genomes of hundreds of avocado trees, scientists pinpointed a gene, SDMYB, associated with the flowering cycle (either type A or type B). This gene exhibits two alleles (alternative versions), akin to the two alternative sex chromosomes found in many other species, one dominant and the other recessive. Type A trees possess one copy of each version, while type B trees have two copies of the recessive version.
Interestingly, the same two versions were identified in 26 other related tree species, suggesting that this genetic mechanism extends beyond avocado trees. This discovery will also benefit avocado producers, as they can now determine a tree’s pollen type during the germination stage and stagger their plantings to ensure cross-pollination occurs throughout the day. Previously, it was necessary to wait for the tree to flower to ascertain this information, a process that could take between 10 and 15 years post-planting.
Sound-Powered Mini-Drones
Most of us have experienced the phenomenon known as Helmholtz resonance in our daily lives—the hum produced when blowing softly over the neck of a bottle, causing the trapped air inside to oscillate. A recent study published in Science Advances reveals that researchers at the École Polytechnique Fédérale de Lausanne (EPFL) have harnessed this effect to create tiny boats and micro-drones powered by sound.
While sound waves have previously been used to levitate objects, the EPFL team sought to convert sound into propulsion. They achieved this by incorporating small hollow cavities made from plastics, polymers, glass, and other common materials through 3D printing into their devices. The sound waves excite the air within these cavities, propelling oscillating air to generate thrust.
The team designed miniature boats featuring three cavities tuned to different audible frequencies, allowing them to steer the craft in specific directions by adjusting the sound frequencies emitted from a speaker. Their 3D-printed micro-drones also included three integrated cavities tuned to ultrasonic frequencies, capable of generating upward thrust or aerodynamic lift similar to that of a helicopter.
Revolutionising Cooling Without Electricity
Traditional refrigerators and air conditioning systems operate using the Carnot cycle, which relies on electric compressors to transfer heat through a refrigerant gas from a high-pressure chamber to a low-pressure one. However, this approach is far from ideal