A Southwest Research Institute team used the James Webb Space Telescope to observe interstellar comet 3I/ATLAS on three dates around its closest approach to the sun. The spectra show a strong water-ice band near 3 microns and gas emission from water, carbon dioxide and carbon monoxide, but the weaker 1.5 and 2.0 micron ice bands are faint or missing. The team says the ice sits in micron-scale aggregates heavily mixed with dust. That signature matches frozen bodies beyond Neptune, suggesting planet-building ice forms in a similar way around other stars.
Astronomers using the James Webb Space Telescope found that water ice in the interstellar comet 3I/ATLAS is bound up with dark rocky material in grains smaller than a few micrometres. The spectrum lacks the weaker ice features usually seen in comets born around the Sun, and instead resembles icy worlds beyond Neptune. The team observed the comet three times with the NIRSpec instrument between August 2025 and April 2026, spanning its closest approach to the Sun. They suggest the building blocks of planets around different stars may share a range of ice grain properties, with 3I/ATLAS sitting at the dust-rich end of that range.
Physicists at Northwestern University have trapped a single positron, the antimatter twin of the electron, and held it for months while reading its quantum states one jump at a time. The work, published in Physical Review Letters on 21 October, is the first one-positron quantum cyclotron. Gerald Gabrielse led the team. Loading one particle into the trap takes eight to eleven hours; a dilution refrigerator cools it to about 300 millikelvin inside a sealed vacuum. The next step is a precise measurement of the positron's magnetic moment, which can be compared with the electron's as a test of CPT symmetry. No difference between matter and antimatter has been found so far.
A study of 485,934 adults in China, followed for a median of about nine years, found that people who drank tea regularly had an 11% lower risk of heart and blood vessel disease than those who did not. During follow-up, 14,863 participants developed cardiovascular, cerebrovascular, pulmonary heart or peripheral artery disease. The benefit appeared strongest among weekly drinkers who had about six to eight cups a day. Black tea showed more consistent links than green tea. The authors and outside experts stress the study is observational and cannot prove that tea protects the heart. Tea of moderate strength was linked to the lowest risk in the analysis.
Researchers at the University of Exeter Medical School have drawn the most complete picture yet of the average human genome, using whole-genome sequences from nearly 900,000 adults in UK Biobank and the US All of Us programme. A typical person differs from the reference sequence at 4.3 to 5.3 million sites, but only about 1.5 percent of those variants are rare. The average genome carries roughly 229 variants predicted to disrupt gene function and one to three classified as pathogenic or likely pathogenic, mostly as healthy carriers of recessive conditions. The team also estimated about 61 new mutations at birth, most inherited from the father.
Researchers at the University of Cambridge and spin-out GlitterinTech have built an optical spectrometer that costs about $10 and measures a few centimetres across. The device reads how light interacts with a substance and identifies foods, plastics and medicines with 100% accuracy in tests. The team says it can also track blood glucose, alcohol and other markers without a needle. Instead of spreading light with a prism or grating, it applies a convolution directly to incoming light, which the researchers say preserves range and resolution at small size. Industrial quality control and food testing are early uses; field results are not yet published.
A study in Astronomy & Astrophysics used carbon monoxide observations, largely from the ALMA telescope, to estimate the carbon-to-oxygen ratio deep inside Uranus and Neptune. Neptune appears substantially richer in oxygen than Uranus, which points to a lower carbon-to-oxygen ratio there. The authors say that split is hard to explain if both planets formed from the same material in the same part of the early solar system. One scenario has Uranus forming near its current orbit and Neptune forming closer to the Sun before migrating outward. Only Voyager 2 has ever flown past either world. The authors say vertical mixing in the deep atmospheres remains the largest source of uncertainty.
Researchers at the University of Bonn and University Hospital of Bonn converted immature red blood cells from an 80-year-old donor directly into neural stem cells, skipping the pluripotent stage, and found the cells carried epigenetic age marks of someone under 20. Rejuvenation was gradual and tracked for over 100 days, with about 60 years erased after 50 days. The slow reset gives scientists a model to test which molecules speed up or slow cellular ageing, which matters for Alzheimer's research because age is the strongest risk factor. The study, in Aging Cell, does not offer a treatment for ageing in people.
The Orionid meteor shower reaches its peak on the night of October 21 and the morning of October 22. The meteors are dust shed by Halley's Comet, which passed through the inner solar system in 1986 and will not return until 2061. NASA says a bright Moon will wash out some of the fainter streaks this year, and the best viewing window is the hours before dawn, after the Moon sets. The shower radiates from the constellation Orion, which rises in the east after midnight.
Japan launched its Martian Moons eXploration spacecraft on Tuesday aboard an H3 rocket from Tanegashima, aiming to return the first samples from Phobos. Liftoff was at 4:41 a.m. local time. The 4,480-kilogram probe will spend about three years in the Martian system, mapping both moons and then landing on Phobos to collect at least 10 grams of material. A capsule is due back on Earth in 2031. Scientists hope the samples will show whether the moons are captured asteroids or debris from an impact on Mars.