Space & Physics
Chandrayaan-3: The moon may have had a fiery past
A magma ocean might’ve wrapped the ancient moon, suggests findings from India’s robotic lunar mission, Chandrayaan-3.
On 23rd August last year, India’s Chandrayaan-3 made history being the first to soft-land on the moon’s south polar region. The landing marked the end of the high-octane phase of the mission. But its next phase was a slow-burner.
Pragyan, the suitcase-sized rover, that hitched a ride to the moon aboard the lander, Vikram, rolled off a ramp onto the lunar surface. It traversed along the dusty lunar surface slowly, at a pace even a snail could beat. Handlers at the Indian Space Research Organization (ISRO) didn’t want the suitcase-sized rover to risk stumbling over a rock or near a ridge, and jeopardize the mission.
The whitish spots are material excavated from the moon’s interior.
Nevertheless, the rover had a busy schedule to stick to. It was to probe the lunar soil, and relay that scientific data back to earth. Pragyan covered 100 meters in two weeks, before it stopped to take a nap ahead of a long lunar night. At the time, the rover’s battery pack was fully charged, thanks to the on-board solar panels soaking up sunlight during the day.
But lunar weather is harsh, especially at the south pole, where Pragyan napped, temperatures can reach as low as -250 degrees centigrade during the night. Added to that, a lunar night lasts two weeks. ISRO deemed Pragyan had only a 1% chance to survive.
Later, the expected happened, when the rover went unresponsive to ISRO’s pings to wake up.
But ISRO said the rover achieved what it was tasked to do. It relayed data all along for two weeks, examining soil from some 23 locations around the mission’s landing point, Statio Shiv Shakti. As months passed by, a slew of discoveries were made. Sulphur was discovered at the south pole, early on while the mission was ongoing. And only a few months ago, Pragyan found evidence of past weathering activity at the south pole.
But since August this year, research teams from ISRO and the Physical Research Laboratory in Ahmedabad, India, reported Pragyan’s most important findings yet – one of which sheds light onto the moon’s origins.
Chandrayaan-3’s Vikram lander, seen from the Pragyan rover’s camera
Moon and the Early Earth
Chandrayaan-3 had carried a radioactive passenger to the moon’s surface – curium-244.
The radioactive curium helps lase the surface: firing alpha particles (which are helium nuclei) at the dusty terrain. Some of these alpha particles bounce off the dust, whereas others evict electrons from the lunar soil, thereby producing x-ray emissions. Keeping watch is the Alpha Particle X-ray Spectrometer (APXS) on-board the Pragyan rover. In August, PRL scientists published findings in the journal, Nature, based on APXS data, reporting discovery of ferroan anorthosite.
It wasn’t the first ever detection per se of ferroan anorthosite. In fact, Apollo 11 had brought back anorthosite rocks to earth, where they were identified as such. That was in 1969, and Apollo sampled them from the equator. Successive missions by the Soviet Union and most recently China affirmed likewise from mid-latitude – equatorial regions as well. But Pragyan’s detection of the rock type was the first ever from the polar region.
The Pragyan rover’s payload.
Anorthosites are common on earth. In fact, just a year after the Apollo 11 sampled the rock, scientists had evidence of the earth and the moon’s entangled history. The authors noted the similar composition between these rocks, that are geographically widespread. Furthermore, ferroan anorthosite is an igneous rock that forms on earth when hot lava produced in volcanic eruptions cools down.
And scientists had piled up evidence in support of a similar process that underwent on the moon. The anorthosite rocks on the moon are old, in fact, more than 4 billion years ago – a figure close to the earth’s inception with rest of the solar system – around 4.5 billion years. Scientific consensus has been that the moon was formed from remnants of a collision between the early earth and a rogue Mars-sized planetary body.
But the collision energy would have yielded a moon that was molten. A lava blanketing the surface – aka a global magma ocean. As this ocean cooled, minerals amongst which is plagioclase (a class of feldspar) crystallized and formed the anorthosite rocks on the moon. It’s commonly called the lunar magma ocean hypothesis.
When Pragyan treaded over the dusty lunar terrain, it didn’t register the anorthosite as a physical rock per se. Instead, it observed remnants of the rock, as fine powder.
Meteorites beat down rocks to fine powder, as they slam into the moon from space with regular impunity. On earth, the ground is saved by the presence of an atmosphere. But the moon virtually has no atmosphere. Nor does it have water to wear down the rocks. The surface is extremely hot during the lunar day – in fact, when Chandrayaan-3 landed on the moon, the surface temperature was some 50 degrees centigrade. Just a few months ago, Pragyan revealed possible signs of rock degradation from the rims of a crater.
Moon dust opens doors to the past
The fact the moon doesn’t (and can’t) sustain an atmosphere helps it make an attractive destination to learn more about our planet and the satellite’s shared origins. There’s no chemistry to remove traces of the moon’s early evolution from the lunar dust. As such, the dust opens doors to the past.
Space explorations missions soft-landing on the surface study this dust – or sample and shuttle them to earth for scientists to study them in detail.
In fact, Pragyan revealed a crater that’s amongst the oldest ever discovered on the moon. The findings were published in the journal, Icarus, in September. Hidden in plain sight, the rover’s navigation camera, NavCam, spotted subtle stretch marks on the surface, that were confirmed later with the Chandrayaan-2 orbiter (which has been orbiting the moon since 2019). In fact, this crater was found buried under nearby craters, most notably the South Pole-Aitkin basin located 350 km away. The basin is the largest impact crater in the entire solar system (some 2,500 km wide and 8 km deep) touted to have formed millions of years ago.
And this became subject to an earlier paper that PRL scientists authored, and was published in August. Pragyan identified material thought to have emerged from the moon’s interior. The APXS instrument picked up unusually high magnesium content in the vicinity. The authors speculate the meteorite that created the basin probably dug up magnesium from deep inside the moon’s upper mantle, and spewed them into Pragyan’s vicinity.
But some experts believe in an alternate explanation. They believe the magnesium might have come from surface rocks in the vicinity, and not from the upper mantle. In fact, the authors acknowledged this amongst other possible alternatives. Nonetheless, the Chandrayaan-3’s findings doesn’t dispute the lunar magma ocean hypothesis either, if not backing it outright. Saying that, the theory lives on to fight another day.
Space & Physics
Indian-Belgian Team Develops Portable Detectors to Image Mountains and Monuments Using Cosmic Rays
Portable cosmic-ray detectors could help researchers examine mountains, tunnels and historical monuments without invasive procedures, opening new possibilities for scientific imaging and infrastructure inspection.
An international team of researchers from India and Belgium has developed portable particle detectors that could help scientists examine the interiors of mountains, tunnels and historical monuments without damaging them. The technology uses naturally occurring cosmic-ray particles to map variations in the density of objects, offering a potential approach to non-invasive imaging of large structures.
The detectors, developed using glass-based Resistive Plate Chambers (RPCs), achieved a particle-detection efficiency exceeding 95% during testing, according to a report published by Research Matters on October 24, 2026. The findings demonstrate the potential of compact detector systems to investigate dense materials and support future applications in geology, archaeology and infrastructure assessment.
The collaboration includes researchers from India’s National Institute of Science Education and Research (NISER), Bhubaneswar, and the Homi Bhabha National Institute (HBNI), alongside researchers from Belgian institutions, including Université catholique de Louvain and the Inter-University Institute for High Energies.
How cosmic rays reveal hidden structures
The technology uses muons, high-energy particles produced when cosmic rays interact with Earth’s atmosphere. These particles continuously reach the Earth’s surface and can penetrate substantial thicknesses of rock, concrete and other materials.
As muons travel through an object, some are absorbed or deflected depending on its density and thickness. By measuring the number and trajectories of particles passing through a structure, researchers can identify variations in internal density and reconstruct images of otherwise inaccessible areas.
The technique, known as muography, is comparable in principle to X-ray imaging, but uses naturally occurring particles instead of an artificial radiation source. It has previously been used to investigate geological formations, including volcanoes, and to explore archaeological structures.
However, conventional muon detectors can be bulky, difficult to transport and challenging to operate in remote locations. The new glass-based detectors aim to address some of these limitations through a compact design and sealed operation, reducing dependence on continuous gas supplies.
Testing the detector system
The researchers developed three glass RPC prototypes using thin glass electrodes separated by gas-filled gaps. When a muon passes through a chamber, it ionises the gas, generating an electrical signal that can be recorded to determine the particle’s position.
Electronic readout systems capture these signals and help reconstruct the trajectories of incoming particles. During testing, the detectors achieved an efficiency exceeding 95%, with a timing resolution of approximately 1.8 nanoseconds, according to the research report.
To examine the system’s ability to detect dense materials, the team conducted an absorption experiment using one prototype. During an open-sky measurement, researchers recorded nearly 55,000 muon tracks. After placing a lead block in the experimental setup, the recorded count fell to 30,894, demonstrating how dense material reduced the number of particles reaching the detector.
Representational image.Image credit:Pexels
The experiment provided proof of principle that the system could measure muon attenuation and support radiographic imaging. However, imaging complex structures such as mountains or monuments requires measurements from multiple directions and further computational reconstruction.
Applications and challenges ahead
Portable muon detectors could eventually help researchers investigate hidden cavities, examine geological formations, inspect tunnels and study the internal structures of historical monuments. Engineers could also explore their application in assessing infrastructure such as dams and bridges, although these uses would require additional testing and validation.
For cultural heritage conservation, muography could offer a valuable alternative where drilling or other invasive investigations risk damaging fragile structures. A 2025 review published in iScience highlighted the technique’s potential as a complementary, non-destructive method for studying cultural heritage objects, while noting that the relatively low flux of naturally occurring muons can require lengthy data-collection periods.
The technology is not yet a universal replacement for existing inspection methods. Its practical application will depend on factors such as spatial resolution, detector size, measurement duration and the complexity of the structure being examined.
The researchers have proposed further improvements, including lighter structural materials, larger detector areas and enhanced readout systems. These developments could make the detectors easier to deploy and improve the quality of reconstructed images.
Space & Physics
How Scientists Traced the Flow of Matter Around a Dead Star Using X-rays
By studying changes in X-ray signals from Centaurus X-3, researchers at Bengaluru’s Raman Research Institute have found evidence of an unusual way in which matter reaches a neutron star. The discovery could change how scientists explain the radiation coming from this distant system.
When a massive star dies, its core can collapse into an extremely dense object called a neutron star. Despite being only about the size of a city, it can have a mass comparable to that of the Sun. Its powerful gravity can pull matter away from a nearby companion star, releasing energy in the form of X-rays as the material falls towards it.
Scientists at Bengaluru’s Raman Research Institute (RRI) have studied these X-ray signals from Centaurus X-3, a star system about 24,000 light-years from Earth. By examining changes in the signals, the researchers identified a stream of matter flowing towards the neutron star and found evidence of a rotating disk of material around it. This is an unusual finding because such disks are not commonly expected in this type of star system. The discovery could help scientists better understand how matter moves around neutron stars and how these distant objects produce X-rays.
Star That Pulls in Matter
Centaurus X-3 is in the constellation Centaurus. It belongs to a class of systems known as high-mass X-ray binaries. These systems contain a neutron star and a massive companion star held together by gravity.
A neutron star forms when the core of a massive star collapses at the end of its life. It packs roughly the Sun’s mass into a sphere only about the size of a city. Its gravity is so strong that it can pull in material from a nearby companion star. As this material falls towards the neutron star, it releases enormous amounts of energy, including X-rays. Scientists study this radiation to understand how the material behaves and how the system works.
Centaurus X-3 is also a pulsar. Its neutron star rotates and sends out radiation from regions near its magnetic poles. As the star spins, these beams sweep across space. When a beam passes an observing satellite, the satellite detects a pulse of radiation, much as a lighthouse produces a repeating flash as it turns. These regular pulses provide scientists with a way to study the neutron star and its surroundings.
What the Changing Signals Revealed
The radiation from Centaurus X-3 does not come only from the neutron star itself. Some of it interacts with nearby material, including the surface of the companion star, gas flowing away from it and matter surrounding the neutron star. This material absorbs radiation and emits it again. Scientists call this secondary radiation.
Changes in this radiation can help researchers work out what is happening around the neutron star. However, Centaurus X-3 is so far away that telescopes cannot clearly distinguish its surrounding structures. It appears as a single point of light. Scientists must therefore piece together the system’s structure from the signals they receive.
Earlier observations had shown that the intensity of certain secondary X-ray emission lines changed as the neutron star rotated. An emission line is a feature in a spectrum that can reveal information about the material producing or interacting with the radiation. A research team led by Kinjal Roy of RRI examined four such emission lines in detail. The researchers found that the structure producing these changes must be rotating along with the neutron star.
The pattern helped them identify the likely source which is a stream of matter moving towards the neutron star.
Following the stream of matter
This stream is part of a process called accretion, in which a compact object draws in material from its surroundings. In Centaurus X-3, the stream carries matter from an accretion disk towards the neutron star. The disk is a rotating structure of gas and other material that moves around the star before being drawn inwards. The neutron star’s magnetic field then guides the incoming matter towards its magnetic poles.
The stream also changes what an observing satellite sees. As it moves around the neutron star, it can come between the satellite and the star, partially blocking the direct radiation. When this happens, the primary X-ray signal weakens. At the same time, radiation from the stream itself becomes stronger in the observed signal.
The researchers used these changing signals to connect the observed variations to the movement of matter around the neutron star. The evidence for an accretion stream also points to an accretion disk feeding it. This matters because scientists generally expect high-mass X-ray binaries to gather material in a different way.
Why an accretion disk matters
In many high-mass X-ray binaries, a neutron star captures gas directly from the stream of material blown away by its companion star. This is known as stellar-wind accretion. An accretion disk involves a different arrangement: material gathers into a rotating structure before flowing towards the neutron star. The findings from Centaurus X-3 indicate that this disk-based process is taking place in a system where it is not generally expected.
That difference matters when scientists calculate how the system produces and releases radiation. If their models leave out the disk, they may fail to account for some of the radiation coming from the surrounding material.
“Accretion disk is not expected to occur in [HMXBs] So, if an accretion disk is forming in this system, emission models have to be modified,” Roy said in the Department of Science and Technology’s announcement. He added that future models of Centaurus X-3 would need to account for radiation from the disk.
The research does not mean that scientists have directly photographed the disk. Instead, they have used the changing X-ray signals to infer the presence and behaviour of structures that remain too distant to resolve clearly. Published in The Astrophysical Journal, the study adds to the understanding of Centaurus X-3, one of the most widely studied binary pulsars. It also shows how small changes in radiation can reveal the movement of matter around objects that are otherwise beyond the reach of direct observation.
By identifying the flow responsible for the changing signals, the researchers have provided a more detailed picture of how this neutron star draws in material. That picture will help scientists refine their models of Centaurus X-3 and examine whether similar processes occur in other high-mass X-ray binaries.
Space & Physics
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