As 2025 draws to a close, we look back at the year and, in the world of science, at the findings that have kept the world on its toes. Space aficionados, in particular, have had a thrilling time. For ages, astronomers have been hunting for exoplanets, uncovering massive cosmic formations like Quipu, and glimpsing the Alaknanda in the James Webb Space Telescope’s mirror (a galaxy similar to the Milky Way). They’ve also tracked a parade of comets, from Lemon to 3I/ATLAS and beyond. Meanwhile, a single, persistent worry loomed—an asteroid impact! Here are five of the year’s most intriguing discoveries.
1. Quipu the largest superstructure:
“This year, a paper entitled “Unveiling the Largest Structure…” was published in the journal ‘Astronomy & Astrophysics’ and has created a stir in the world of astronomy. Researchers from the Max Planck Institute for Extra-Terrestrial Physics and the Max Planck Institute for Physics have discovered the largest structure in the universe, ‘Quipu.’ The supermassive structure of about 200 quadrillion solar masses (1 solar mass = 1.988416 × 1030 kg) was detected during the mapping of the nearby universe with the help of the ROSAT X-ray satellite. The size and mass of this object are incomprehensible; it occupies 428 megaparsecs (1 ‘megaparsec’ = 32.6 light years) of space, and light takes thirteen million years to pass through it, according to scientific estimates.
Max Planck’s scientist, Hans Boehringer, and his colleagues named the structure Quipu. Why such a strange name? The Inca civilization of Central America had the practice of knotted ropes in the counting system. Boehringer saw the ropes at a museum near Santiago, Chile, while working at the European Southern Observatory. That’s why the name. Another reason is that the distances of most galaxy clusters were measured at the Southern Observatory of Chile. Basically, a thick rope is tied with several thin ropes around it in the form of a ‘Quipu,’ just like in the ancient Inca script.
Astronomers hope that in the future, such research will help improve existing cosmological models. “If these cosmological measurements can only be corrected by a few percent, they will become more important as the accuracy of cosmological observations increases,” said Gayoung Chon, a principal investigator on the project.
2. K12-18b exoplanet:
Scientists have been observing the sky with binoculars since ancient times. With the passage of time, they have come up with powerful telescopes like Hubble and James Webb. Scientists from the University of Cambridge, using NASA’s James Webb Space Telescope, have discovered life on a planet called ‘K12-18 b,’ 128 light-years away from Earth.
They found the presence of two chemical gases, dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), on this planet, which is 8.6 times larger than our Earth. They mainly produce marine phytoplankton-algae. That is, the researchers speculate that the imprint of a biological process may be there. As technology advances, we can learn more about it.
3. Life on Mars!
Scientists have been searching for water on Mars for a long time. Water is not the only element of life, but it is the most important. In a study published in Nature on September 10 this year, a group of scientists claimed that traces of life were found in rock samples called ‘Cheyava Falls’ collected on NASA’s Perseverance rover. The stone, which is 6 square feet in size and shaped like an arrow, was found in a place (Jezero pit) where the river used to flow.
Scientists have collected small samples from the rock found by the rover and reviewed them over the past year. They named the specimen ‘Sapphire Canyon.’ In the initial analysis, they claimed that the stone is rich in organic compounds. It found vivianite, a type of iron phosphate found near decomposing organic matter on Earth, and graizite, an iron sulfide. Usually, their combination is seen as an indication of possible life on Earth.
Long scars have been found on the Cheyava Falls, proving that water once flowed through the rocks. Scientists believe that some chemical reactions related to ancient microorganisms are behind these stains. However, scientists are not yet sure if the stains are due to an unknown chemical reaction. Since 2021, scientists have collected and stored samples from various parts of Mars in 10 titanium boxes for further confirmation. Therefore, we may have to wait a few more years to determine whether there was indeed life on Mars billions of years ago, how long it existed, and how the climate there changed.
4. New Moon of URANUS:
The planets of our solar system have different numbers of moons; the largest, Jupiter, has 95, Saturn has 274, and Earth has only one satellite. There are no satellites of Mercury or Venus. Recently, scientists discovered a new moon of Uranus called S/2025 U1, which is only 10 kilometers in diameter. Because of its small size, astronomers had not noticed it for a long time. The moon was discovered by the James Webb Space Telescope’s infrared camera on February 2. At present, Uranus has 29 satellites. There are 13 rings around Uranus, and scientists believe that there are more moons hidden behind them. So we have to wait more for the total number of moons on this ice-cold planet.
5. 3I/ATLAS Comet:
Comets Swan (C/2025 R2) and Lemmon (C/2025 A6) were discovered in October this year. Since July, the interstellar comet 3I/ATLAS has been the center of attention for space enthusiasts. Recently, on December 19, this celestial object came closest to the Earth (approximately 1.8 astronomical units away). What is 3I/ATLAS?
It is usually composed of solid ice (water, carbon dioxide, etc.) and dust and rocks, with a core extending from 0.6 to 5.6 km, surrounded by a continuous cloud of gas and dust. It looks like an inverted tail, which is called an ‘anti-tail.’ Astronomer Larry Deneau discovered this celestial object while observing the night sky on July 1, 2025.
Denneau was involved with the Asteroid Terrestrial Impact Last Alert System (ATLAS), which monitors asteroids or celestial objects that may strike Earth. It is part of the Institute for Astronomy at the University of Hawaii. ATLAS uses four telescopes, two in Hawaii and two in the Southern Hemisphere, to keep track of celestial objects long before they reach Earth’s edge.
(The writer is associated with the Physics Division, State Forensic Science Laboratory, Kolkata)