Articles by TOI SCIENCE DESK

Science

How 39,000-year-old ancient RNA from a mammoth found in Siberia reveals its biology

The recovery of ancient RNA from a woolly mammoth preserved in Siberian permafrost has offered scientists a rare look into the workings of an animal that lived nearly forty thousand years ago. RNA usually breaks down soon after death, which makes its presence in the Ice Age remain highly unexpected. Yet the cold, stable conditions of deep permafrost have kept delicate cellular material intact, allowing researchers to examine gene activity that once shaped the mammoth’s body. The discovery is generating attention within scientific discussions on how long biomolecules can endure and what they can reveal about extinct species. It provides an unusual chance to study ancient biology at a level of detail that is seldom possible.Where and how the 39,000-year-old mammoth was discoveredThe mammoth studied was found near the Laptev Sea coast in Siberia, a region known for preserving Ice Age creatures with remarkable clarity. The individual, often referred to as Yuka, had remained locked in frozen ground for around 39,000 years. Much of its soft tissue, including skin and muscle, was still recognisable when excavated. This level of preservation is closely linked to the conditions of the site. The permafrost remains deeply frozen throughout the year, creating a natural vault that protects remains from bacteria, moisture and fluctuating temperatures.Such stability is essential for the survival of RNA. Even slight warming can trigger rapid molecular decay, yet the sediments surrounding Yuka showed long-term cold conditions that slowed these processes dramatically. The mammoth’s rapid burial in dense frozen soil also shielded it from environmental shifts that might have damaged the tissues. Because of this, the recovered samples held tiny but valuable fragments of RNA, which researchers could sequence with modern techniques. The fact that such material endured for almost forty millennia illustrates how powerful the preserving effect of permanently frozen landscapes can be.What the ancient RNA reveals about mammoth biologyOnce extracted, the RNA gave scientists a set of clues about the mammoth’s biology at the time of its death. The sequences, although fragmented, contained enough information to identify genes involved in muscle structure, cellular maintenance and energy use. These transcripts are not just records of genetic code but indicators of which genes were active in living tissues. Their presence suggests that the mammoth’s cells were performing normal functions shortly before death.Some transcripts reflected activity linked to stress, hinting that the animal may have experienced physical strain or environmental pressure near the end of its life. The exact cause cannot be confirmed, but the signals were consistent with what is seen in modern mammals when muscles respond to demanding conditions. The researchers compared the sequences with the genomes of elephants, the mammoth’s closest living relatives. This comparison helped confirm the authenticity of the RNA and showed a strong resemblance in basic cellular processes. These findings highlight how ancient RNA can reveal not only genetic information but also snapshots of cellular behaviour, something that traditional fossil evidence cannot provide.What techniques made 39,000-year-old RNA analysis possibleRecovering RNA this old required laboratory methods designed for extremely fragile material. The study, published in Cell, used specialised extraction steps that protected the delicate fragments from further damage. Modern sequencing platforms were then adapted to detect small and degraded strands, enabling scientists to piece together meaningful patterns from molecular traces.Strict contamination controls were essential. Ancient samples can easily pick up modern RNA, so researchers used genetic comparisons to separate genuine mammoth sequences from anything introduced after excavation. Only fragments that clearly matched known mammoth or elephant genes were included in the analysis. These advances show how far palaeogenomics has progressed. Several years ago, the possibility of sequencing RNA from an animal that died almost forty thousand years ago seemed limited by technology. Improvements in precision and sensitivity have now made it possible to explore gene activity in organisms long removed from the modern world.How the surroundings explain the mammoth’s worldThe sediments surrounding Yuka offered further information about the world the mammoth once inhabited. The landscape would have been part of the mammoth steppe, a cold but productive ecosystem that stretched across northern Eurasia. The soil preserved traces of grasses and hardy plants that supported large herbivores. This environment favoured species adapted to low temperatures, and the layers of frozen ground reflect the stability of that climate.These same conditions that shaped mammoth life also protected its remains. The continuous cold created an environment where tissues and molecular structures could remain intact for thousands of years. As climate change alters permafrost regions, researchers are increasingly aware that many such specimens may emerge more frequently. However, once exposed to warmer air, their molecular information can deteriorate quickly. Yuka’s RNA highlights both the scientific value of these frozen archives and the urgency of studying them before they decay.Also Read | How stellar eruptions might shape the fate of alien worlds: Could distant stars threaten exoplanets

Technology

3I/ATLAS may be the oldest comet ever seen in 7 billion years

Astronomers have discovered an ancient, ice-rich interstellar object called 3I/ATLAS, which could transform our understanding of how comets form and evolve. Detected by the University of Oxford’s research team, this mysterious object is believed to have originated far beyond our solar system, possibly more than seven billion years ago. Its immense age suggests it predates the Sun and planets, making it potentially the oldest comet ever observed. Unlike typical comets formed within our solar system, 3I/ATLAS appears to originate from the Milky Way’s thick disk, a region rich in ancient stars. Scientists say its composition and trajectory could provide vital clues about the early galaxy and the interstellar processes that shaped the formation of stars and planetary systems.3I/ATLAS: A rare visitor from beyond our solar system identifiedThe discovery of 3I/ATLAS marks only the third time astronomers have identified an object entering our solar system from interstellar space. Unlike previous visitors 1I/ʻOumuamua (2017) and 2I/Borisov (2019), this comet is thought to have originated from a completely different region of the Milky Way Galaxy.According to Dr Matthew Hopkins, an astronomer at the University of Oxford, the object’s orbit indicates it came from the galaxy’s thick disk, a vast area populated by ancient stars. This region lies above and below the thin, flat plane where the Sun and most stars reside. Hopkins presented the findings at the Royal Astronomical Society’s National Astronomy Meeting 2025 in Durham.“All comets within our solar system, such as Halley’s, formed about 4.5 billion years ago,” said Hopkins. “But interstellar comets like 3I/ATLAS may have formed long before that, potentially making this the oldest comet ever observed.”Discovery of 3I/ATLASThe object was first detected on 1 July 2025 by the ATLAS survey telescope in Chile. At the time, it was about 670 million kilometres from the Sun, travelling on a steep and unusual orbit that immediately caught astronomers’ attention.Hopkins and his team applied a statistical model originally developed during his doctoral research, which predicts the age and composition of interstellar comets based on their orbits and likely stellar origins. Their analysis indicated that 3I/ATLAS likely formed around an ancient, thick-disk star, suggesting it contains a high concentration of water ice.“This is an object from a part of the galaxy we’ve never seen up close before,” said Professor Chris Lintott, co-author of the study and presenter of BBC’s The Sky at Night. “There’s a two-thirds chance this comet is older than the solar system itself, a true relic from our galaxy’s distant past.”3I/ATLAS shows early signs of activity as it nears the sunAs 3I/ATLAS moves closer to the Sun, scientists expect it to become more active. The increasing heat will cause sublimation, the release of gas and dust from its icy surface, producing a bright coma and tail, the hallmarks of a comet.Initial observations already show signs of such activity, hinting that 3I/ATLAS could be larger and more dynamic than its predecessors ʻOumuamua and Borisov. This makes it a valuable target for upcoming astronomical missions.According to Dr Michele Bannister from the University of Canterbury in New Zealand, “We’re entering an exciting phase. As 3I warms up under the Sun’s light, we’ll be able to study the gases it releases, providing a rare glimpse into material formed in another part of the Milky Way.”What makes 3I/ATLAS comet more significant The potential age of 3I/ATLAS sets it apart. Formed around ancient stars, it may carry chemical signatures from the early Milky Way, preserving information about the conditions that existed long before the Sun was born. Studying its composition could offer insights into how interstellar comets contribute to star and planet formation throughout the galaxy.Moreover, its trajectory shows that it travels deep into the outer thick disk, a region rarely sampled by astronomical observations. The Sun, by contrast, orbits closer to the galactic plane, highlighting how extraordinary it is for material from such a remote area to reach our neighbourhood.3I/ATLAS discovery sparks hope for more interstellar findsThe timing of 3I/ATLAS’s discovery is particularly striking. Hopkins and his colleagues were preparing for survey operations with the Vera C. Rubin Observatory, expected to transform our understanding of transient cosmic objects.“The Rubin Observatory is projected to detect between five and fifty interstellar objects in the coming years,” explained Dr Rosemary Dorsey from the University of Helsinki. “But the discovery of 3I suggests we may find even more, perhaps dozens of these ancient wanderers.”The Rubin telescope, with its wide-field imaging capability, will allow astronomers to track interstellar objects in greater detail than ever before. Such discoveries could redefine how we think about the origins of comets and their role in spreading organic materials across galaxies.3I/ATLAS discovery turns Hopkins’ research into realityIronically, the discovery came just a week after Hopkins defended his doctoral thesis, which focused on modelling interstellar comet populations. He had planned a quiet holiday but was instead met with a flurry of messages after 3I/ATLAS was confirmed.“Rather than a calm Wednesday, I woke up to messages saying ‘3I!!!!!!!!!!’,” he recalled. “It’s thrilling to test our theoretical model on a brand-new, possibly ancient object in real time.”The team has since published its analysis as a preprint on arXiv, introducing the Ōtautahi–Oxford Model, the first predictive framework successfully applied to a newly discovered interstellar comet.How and when to see 3I/ATLASFor astronomy enthusiasts eager to witness history, 3I/ATLAS should become visible through medium-sized amateur telescopes by late 2025 and early 2026, depending on its brightness and activity.As it continues its journey through our solar system, scientists hope it will reveal more about the ancient origins of comets, the evolution of galaxies, and the interstellar chemistry that may one day explain how life began in the universe.Also Read | 3I/ATLAS sending mysterious Fibonacci-pattern pulse signal 8 • 13 • 8 • 5 • 13 • 8 at 1420 MHz; could it be a message from deep space