Category: science

Marine mammals rely on oxygen to survive, yet some species stay underwater for long periods without breathing. Scientists at the University of St Andrews wanted to understand how gray seals manage their time underwater without relying on carbon dioxide buildup as a signal. Six adult gray seals were placed in a controlled environment to observe their diving patterns. The seals were only allowed to surface at a designated chamber, where researchers adjusted oxygen and carbon dioxide levels to test their responses.

Research Confirms Oxygen as the Primary Trigger

According to the study published in Science, different air compositions were tested to measure their effect on dive times. The air in the breathing chamber was adjusted across four conditions: normal air, increased oxygen, reduced oxygen, and heightened carbon dioxide levels. When oxygen levels were increased, seals stayed underwater for longer. When oxygen was reduced, they surfaced sooner. Carbon dioxide changes did not alter their behavior, suggesting that oxygen, not carbon dioxide, determines when they come up for air.

Unique Adaptation in Marine Mammals

Researchers says that grey seals have an internal system to track oxygen levels. This allows them to surface before reaching dangerous limits. This ability prevents drowning and may be common among other marine species. Since deep-diving mammals must manage oxygen carefully, similar mechanisms could be present in whales, dolphins and other seals.

Experts Weigh in on the Discovery

Lucy Hawkes from the University of Exeter and Jessica Kendall-Bar from the University of California, San Diego, discussed the study’s impact. They noted that understanding this adaptation sheds light on how marine mammals survive in extreme underwater conditions. Further research could explore how this system works in different species and environments.

A striking nebula shaped by the dynamic interactions of two young stars has been observed in unprecedented detail by the James Webb Space Telescope (JWST). The structure, identified as Lynds 483 (LBN 483), is located approximately 650 light-years away. The nebula’s intricate shape is a result of powerful outflows generated by the formation of a binary star system. As material from a collapsing molecular cloud feeds these stars, bursts of gas and dust are expelled, shaping the surrounding nebulosity into a striking hourglass-like formation. The interaction of these stellar winds and jets with surrounding matter continues to sculpt the nebula over time, providing valuable insight into the mechanisms of star formation.

Star Formation and Nebular Evolution

According to reports, the two protostars at the core of LBN 483 play a crucial role in shaping the nebula. The presence of a lower-mass companion star, identified in 2022 through observations by the Atacama Large Millimeter/submillimeter Array (ALMA), suggests complex interactions within the system. Material accreted onto the stars periodically fuels energetic outflows, which in turn crash into the surrounding gas and dust. The JWST’s infrared imaging has revealed intricate structures within these lobes, including dense pillars and shock fronts where ejected material meets older expelled gas.

Impact of Magnetic Fields on Nebular Shape

Radio observations from ALMA have detected polarised emissions from cold dust within the nebula. These emissions indicate the presence of a magnetic field, which influences the direction and structure of the outflows. The study highlights a distinct 45-degree kink in the field at a distance of approximately 1,000 astronomical units from the stars. This deviation is attributed to the migration of the secondary star over time, altering the system’s angular momentum and consequently shaping the nebular outflows.

Implications for Star Formation Studies

LBN 483 presents a unique opportunity for astronomers to study star formation outside of massive stellar nurseries such as the Orion Nebula. The nebula’s isolation allows researchers to examine the formation process without interference from external stellar activity. Findings from this study contribute to refining theoretical models of star formation by integrating real observational data into numerical simulations. Scientists continue to analyse such systems to gain a deeper understanding of how stars, including the Sun, evolved from collapsing clouds of gas billions of years ago.

The world’s largest iceberg, A23a, has come to a standstill near South Georgia, a critical wildlife habitat in the South Atlantic. The British Antarctic Survey (BAS) confirmed on March 4 that the iceberg, comparable in size to Rhode Island, had run aground approximately 80 kilometres from the island. Having drifted through the Southern Ocean for months, its trajectory has been closely monitored by researchers. Scientists are now evaluating its potential impact on the region’s delicate ecosystem, particularly its effect on penguins, seals, and marine life.

Iceberg’s Journey and Previous Movements

According to the British Antarctic Survey, A23a initially calved from Antarctica’s Filchner Ice Shelf in 1986 but remained grounded on the seabed for decades. It began moving again in 2020, later getting temporarily stuck near the South Orkney Islands in early 2024. After breaking free in December, it continued northwards toward South Georgia. Scientists had previously raised concerns over its approach, fearing disruptions to the region’s biodiversity.

Impact on Wildlife and Marine Ecosystem

As reported by the BBC, Andrew Meijers, an oceanographer at the British Antarctic Survey, stated that if A23a remains stationary, significant threats to local wildlife are unlikely. However, should the iceberg shift closer to the island or fragment, challenges could arise. Meijers noted that disruptions to feeding pathways may force adult penguins and seals to travel longer distances, reducing the food supply for their offspring and potentially increasing mortality rates.

Potential Benefits and Risks

Marine ecologist Nadine Johnston told the BBC that the iceberg could also stimulate ocean productivity by introducing essential nutrients into surrounding waters. She described this phenomenon as a “nutrient bomb” that could enhance food availability for predators such as penguins and seals. On the other hand, commercial fishing operations may face obstacles. As per BAS reports, previous iceberg breakups have disrupted fisheries, and A23a’s eventual fragmentation could pose navigation hazards.

Ongoing monitoring will determine how A23a’s presence affects the South Georgia ecosystem in the coming months.

A rare ‘gigantic jet’ of lightning has been photographed from space, extending nearly 50 miles above the U.S. coastline. The image was taken by an astronaut aboard the International Space Station (ISS) on November 19, 2024, but was not immediately shared by space agencies. The phenomenon was later discovered on NASA’s Gateway to Astronaut Photography of Earth website by photographer Frankie Lucena, who specialises in capturing rare lightning events. The images were subsequently highlighted by Spaceweather.com on February 26.

Jet Likely Originated Over Louisiana

According to Spaceweather.com, the ISS was positioned over the Gulf of Mexico at the time of the capture, suggesting that the lightning jet likely originated from a thunderstorm near New Orleans. Due to dense cloud cover in the image, the precise location could not be determined. Four images of lightning were identified in the astronaut’s photography sequence, but only one captured the distinct upward-shooting jet.

Understanding Gigantic Jets

Gigantic jets are powerful electrical discharges that travel upward from thunderstorms when charge layers within the clouds become inverted. Unlike conventional lightning that strikes downward, these jets extend into the ionosphere, the atmospheric layer beginning around 50 miles above the Earth’s surface. As per Spaceweather.com, these jets emit a blue glow due to interactions with nitrogen in the upper atmosphere and last for less than a second.

Uncommon but Extremely Powerful

Reports indicate that while gigantic jets were first documented in 2001, scientists estimate that around 1,000 could occur annually, though most go undetected. The most powerful recorded jet was observed in May 2018 over Oklahoma, carrying nearly 60 times the energy of a typical lightning strike. These events often conclude with red branching tendrils, similar to lightning phenomena known as sprites, but classified as separate occurrences.