New Dwarf Planet Beyond Pluto Could Be Among the Kuiper Belt’s Largest

This is Space Time, Series 29, Episode 131, for broadcast on the 2nd of November, 2026. Coming up on Space Time, the discovery of a new dwarf planet beyond Pluto, the European Space Agency's new planetary defence mission finally sees its target, and the Russians permanently close off part of their section of the International Space Station due to ongoing leaks. All that and more coming up on Space Time. Welcome to Space Time with Stuart Gary. Astronomers have discovered a new dwarf planet in the outer reaches of the solar system beyond the orbit of Pluto. This new world, catalogued as 2026 AD 138, was detected in observations by the Vera C. Rubin Observatory. If confirmed through follow-up observations, it would be among the largest and brightest dwarf planets ever discovered in the Kuiper Belt, that region populated by frozen worlds, comets and icy debris which circles the Sun beyond the orbit of Neptune. The study's lead author, Matthew Holman from the Harvard-Smithsonian Center for Astrophysics, says his first reaction was one of excited disbelief as objects like this are very rare. Holman was running data collected by Rubin earlier this year using a search code built to look at billions of detections of moving objects, compare them and find the detections that correspond to the same object. The program uncovered 2026 AD 138, and Holman immediately noticed that its brightness and distance indicated that it was unusually large. So he checked to see whether he or the code had been in error in some way, and to remove any remaining doubt, he then conducted a detailed search uncovering 30 more observations of AD 138 going back to March 4, 2026. Then additional archival images were also dug up from the Dark Energy Camera, which detected further observations going back to 2016, providing over 10 years of ED-138's orbital data. So what do we know? 2026 ED-138 is a trans-Neptunian object. That's an object that orbits the Sun at a greater distance than Neptune's orbit. ED-138 is currently at a distance of about 46 astronomical units. An astronomical unit is the average distance between the Earth and the Sun, about 150 million kilometres or 8.3 light minutes. Now by comparison, Neptune orbits the Sun at around 30 astronomical units, and Pluto's highly elliptical orbit ranges from 29.7 to 49.5 astronomical units. Scientists studied the size, composition, and orbital trajectories of trans-Neptunian objects to understand how the solar system was formed, how the giant planets migrated over time, and how smaller objects have been scattered throughout this evolution. ED-138's orbit is tilted almost 25 degrees off the ecliptic, the planet of the solar system, classifying it as a hot classical trans-Neptunian object, suggesting that it was disturbed from its original orbit through gravitational interactions with Neptune. To be a dwarf planet, an object needs to be massive enough to be self-gravitating, that is, to pull itself into a roughly round shape. Now, based on AD 138's distance, its brightness, and its estimated surface reflectivity, that is, its albedo, the authors estimate that it's somewhere between 600 and 1500 kilometers wide, and icy bodies this large are expected to be round. This preliminary analysis places ED-138 among the largest dwarf planet candidates ever discovered beyond Neptune, though observations in the infrared are still needed to constrain its exact size and confirm its nature as a dwarf planet. If confirmed, ED-138 will join five other dwarf planets recognized by the International Astronomical Union, those being Pluto, Ceres, Eris, Humira, and Makemake. ED-138 was found in a region of the sky close to the plane of the Milky Way, a crowded region filled with millions of stars. And in most telescopes, this world would have been lost among the myriad of background sources, which is likely why it wasn't discovered until now. But Rubin's regular and continuous monitoring of the entire southern hemisphere sky, combined with powerful algorithms that sift through millions to billions of points of light to identify those corresponding to small moving objects, enabled the authors to spot ED-138 within this crowded field. This is space time. Still to come, the European Space Agency's planetary defense mission finally sees its target, and Russia permanently closes off part of the International Space Station because of ongoing leaks. All that and more still to come on Space Time. The European Space Agency's Hera spacecraft has now spotted its target asteroids, Didymos and Dimorphos, achieving first light in its planetary defence mission. The binary system is currently 197 million kilometers from Earth and was imaged by HERA at a distance of 1,280 kilometers. Prior to these new observations, the binary looked like just a single blurry dot. This first image of the separated pair follows the success of HERA's braking maneuver earlier last month when a pair of thruster burns a week apart slowed the spacecraft to just 20 meters per second relative to the asteroid's movement. Dimorphos is just 151 meters wide and orbits around its 780-meter-wide partner Didymos at an average distance of 1.15 kilometers, traveling at an average speed of 18 kilometers per second. Back in September 2022, Dimorphos became the subject of a grand-scale planetary defense experiment when NASA's DART spacecraft was deliberately impacted into the small asteroid at a velocity of 6.1 kilometers per second. The resulting collision sent out a massive plume of debris covering an area of some 10,000 kilometers of space, and it slowed the asteroid's orbit by around 33 minutes. But there remains key unknowns to turn this kinetic impact method into a well-understood planetary defense technique. Astronomers need to know what the impact did to the asteroid itself. Did it leave a crater, or did it reshape the asteroid's body entirely? Astronomers also want to know the precise makeup, structure and mass of Dimorphos, and which properties explain why their deflection was so much greater than simulations had predicted. Over the coming months, ERA will perform a close-up crash site investigation of Dimorphos, harnessing multiple instruments and deploying a pair of small shoebox-sized CubeSats for a still closer survey, and eventually landing on the asteroid itself. This report from ACTV. Years ago, NASA made history by intentionally slamming into an asteroid with its DART mission. The asteroid wasn't a threat to us here on Earth, but scientists wanted to see if they could change the path of an asteroid to test a technique that could one day protect us from a real threat. The experiment was a success. Humans can move an asteroid. But the bad news is that scientists aren't sure yet they understand why it worked. There is still a lot we don't know, like what exactly happened on the asteroid surface after the impact, what the asteroid is made of and how well the deflection worked. But our HERA spacecraft will soon answer all of our questions. HERA will perform a close-up crash scene investigation. gathering data on the asteroid's mass, structure and makeup to turn this kinetic impact method of planetary defence into a well-understood and repeatable technique. Why do we need to protect our planet? In 1908, people reported a bright flash and a noise that sounded like a bomb 10 minutes later. This was from the largest observed asteroid strike ever recorded, which occurred over the Tunguska region in Siberia. People up to 500 miles away reported seeing the flash. Some claimed it was even brighter than the sun. The explosion was massive, causing 80 million trees to flatten, windows up to 250 miles away to smash, and the effects of the shockwave could even be felt in London. This represented a lucky escape for Europe. It happened just a short distance from affecting heavily populated regions. As a result, ESA, NASA and other space agencies started closely monitoring space to track potentially dangerous asteroids. So far, we have found more than 35,000 asteroids whose orbits bring them dangerously close to Earth. But if one was on a collision course with us, what could we do? To answer this question, an international team came up with the first planetary defence mission. DART to hit the asteroid and HERA to gather data after the impact. Knowing there are so many asteroids that could be a danger to us, how did we pick one to explore? The asteroid that DART hit and that our HERA spacecraft will now visit is called Dimorphos. It's a small asteroid, about half the size of the Eiffel Tower, but if it impacted Earth, it could devastate a small country or city. Dimorphos orbits a larger asteroid called Didymus, which Hera will also visit. Together, the two asteroids form the Didymus system. Here are some of the reasons why scientists decided to explore the Didymos system among all the asteroids out there. The two asteroids are not a real threat to Earth so nudging one of them wouldn't accidentally set it on a crash course to Earth. The system passes relatively close to Earth so they are not impossible to get to. The 150-metre diameter of Dimorphos is important. We know about 95% of all near-Earth objects larger than one kilometre in size, but the majority of smaller asteroids are yet to be discovered, despite their city-killing potential. Since Dimorphos orbits Didymus, we can easily see any changes in its orbit from Earth. So, what are we expecting to see on Dimorphos? We asked one of our experts, Patrick Michel, the principal investigator of the HERA mission to find out more. So what do we expect to find on Dimorphos? That's a big question. Actually, we don't really know because the DART mission by NASA made an impact on Dimorphos and based on the current data that we have from this mission, there are different solutions. So Dimorphos may host a crater whose size is unknown or it could be completely reshaped. Prior to DART's impact, it took Dimorphos 11 hours and 55 minutes to orbit its larger parent asteroid. Since the collision, astronomers have found that the spacecraft's impact altered Dimorphos' orbit around Didymus by 33 minutes, shortening the orbit to 11 hours and 22 minutes. The mission was deemed a large success, but to learn more about these asteroids' physical properties and DART's impact outcome, we need to visit them. Initially, we thought that when DART crashed into Dimorphos, it would create a big impact crater, potentially the first one ever made by humans. But now, scientists think there might not be a crater on Dimorphos after all. More recent simulations suggest the impact might have completely changed the asteroid's shape. Scientists estimate that around 8% of the asteroid's mass was shifted around its body, and 1% of the entire mass of Dimorphos was thrown into space. some of which may reach as here at Earth as small meteoroids. So the dark impact generated a lot of ejecta, a lot of material that is still escaping from the system at tens of thousands of kilometers from the morpheus. And it may be that some small particles eventually reach Mars or the Earth, but in the form of shooting stars, like what you see in the sky during the night, so with no risk. We don't know. What it looks like now. So there's going to be a lot of surprises. I'm so excited because we'll have the answer. Crater or no crater, we need to go back to Dimorphos to study the aftermath of the impact. This will help us turn the dark deflection experiment into a well-understood, repeatable technique that might one day be needed for real. Didymus' gravity is estimated to be around 40,000 times weaker than Earth's. While Dimorphosis is approximately 200,000 times weaker, this is so low that Hera must orbit around their common centre of gravity at very low velocity to remain captured. To maintain the optimal distance for studying the asteroids, Hera's orbit will need regular adjustments, otherwise the spacecraft could gradually drift away from them. The possibility of Hera touching down on one of the poles of Didymus at the end of its mission is being considered. Although it has not been specifically designed for landing, it could descend towards the surface. However, once on the surface, Hera will no longer be able to communicate with us on Earth, effectively bringing the mission to an end. What types of technology do we need to inspect an asteroid? It is packed with new technologies which will allow us to study the asteroid in extraordinary detail. HERA carries a total of 12 instruments to explore the Didymos system. It has a state-of-the-art camera which will take detailed pictures of the asteroids, a laser altimeter which will create a map of the asteroid's surface, a camera which can look at the asteroids in different colours of light to find out exactly what they're made of, a radio science experiment which can use radio waves to figure out the mass and gravity of the asteroids. To explore Dimorphos and Didymus, here it doesn't go by itself. Instead, the spacecraft carries two shoebox-sized CubeSats that resemble terrestrial drones, able to fly closer and take more risks and eventually even land a world first. This is the first time that we send a spacecraft equipped with two CubeSats that will do deep space exploration of an asteroid. And the reason why we bring these CubeSats is because you want to go at very close proximity of the asteroid, and we don't want to pose any risk to the main spacecraft. And these two CubeSats will contain their own instruments, and for the first time, for instance, we'll be able to probe the internal property of an asteroid, which has never been done so far, and that's on the Juventus CubeSat. On the second CubeSat, Milani, we'll measure the mineralogical composition of the asteroid and detect whether there is still dust around the body. The two CubeSats called Juventus and Milani will get up close and personal with the asteroid. Juventus will use radar, sending out radio waves that will bounce off the asteroids and come back. By measuring how long it takes for the waves to return, we will be able to tell how far away the asteroid is at any given point and even what shape it is. More importantly, it will allow us to explore what an asteroid is like on the inside for the first time. Is Dimorphos a rubble pile or a monolith covered with pebbles and gravels? Once it has inspected both asteroids, it will then descend to Dimorphos' surface to take detailed pictures of the surface features, including hopefully the exact spot of the dart impact. Once on the ground, it will use a gravimeter to increase our knowledge of the gravity field of the asteroid. The other CubeSat, Milani, will measure the mineralogical composition of the asteroid and will analyse any surrounding dust. Later on, it will also attempt a landing on Dimorphos. Its onboard instruments will gather valuable data on the landing and any subsequent bounces to give insights into the surface properties of the asteroid. If Milani lands safely, its VISTA instruments will analyse the dust on Dimorphos' surface. By the end of the six-month exploration by these three spacecraft, scientists will have a better understanding of the delicate art of asteroid deflection, and asteroid impacts will become the first avoidable natural disaster. At first glance, an asteroid is just a tiny dot of light in the sky. We require more observations to see if it is a real threat. Planetary defence is a global problem and therefore we need to be able to work together with other space agencies to protect our planet, and HERA is the perfect demonstration of that. And in that report from ESA TV, we heard from HERA Principal Investigator Patrick Michel. This is Space Time. Still to come, Russia permanently closes off part of its space station segment due to ongoing leaks. Later in the science report... A dire warning from Anthropic, which claims artificial intelligence could wipe out all human existence. All that and more still to come on Space Time. Space Time Mission managers at Star City near Moscow have been forced to permanently close off one of the compartments of the Russian Zvezda module on the International Space Station because of a persistent structural leak venting atmosphere into space. The unstoppable leak was caused by stress fractures and cracks in the hull, and it's been steadily getting worse since first detected back in 2019. Cosmonauts actually discovered two air leaks during a series of inspections. One small leak was eventually sealed, but the other was in a difficult-to-reach area and couldn't be repaired. Numerous attempts to plug the leak have failed, forcing the Russian Federal Space Agency at OSCOSMOS to now issue an order to isolate the compartment. Moscow says constant pressurising and depressurising of the PRK transfer tunnel compartment, which is at the aft end of the Zvezda module, has caused the structural cracks to grow, leading Roscosmos to make the decision to halt further attempted repairs and simply permanently close off the hatch, isolating the area from the rest of the space station. This PRK transfer tunnel compartment links Zvezda's main working compartment to the rear docking port, which was being used by visiting Progress cargo ships and for space station reboosts. So the closure means future Russian Progress cargo ships will now have to dock at one port for cargo unloading, then re-dock at the aft port to perform ISS orbit raising and re-boost manoeuvres. The 13.1 metre long 20 tonnes Vesta module is a wingspan of 30 metres from tip to tip of its solar arrays, and it contains three pressurised compartments. There's the spherical PKHO transfer compartment that's at the forward end, the long cylindrical RO main working compartment and the now closed-off PRK cylindrical transfer chamber at the aft end of the RO section. An unpressurised aggregate compartment is wrapped around the exterior of the PRK chamber at the aft end of the module. The Zvezda is designed to help maintain the orbiting outpost in its correct position in space, using two large and 16 small thrusters, pressure-fed from four tanks, with a total capacity of 860 kilograms of dinitrogen tetroxide oxidizer and unsymmetrical dimethylhydrazine fuel. The module also supplies and distributes electrical power from its solar panels to the Russian section of the space station, and it sends, receives and processes flight control information using internal computers. This is Space Time. And time now to take a brief look at some of the other stories making news in science this week with a science report. Anthropic, the organization behind the artificial intelligence Claude, has now warned that AI could wipe out human existence. The warning comes as the $ 2 trillion company lists on the US Stock Exchange. In a filing ahead of its listing, Anthropic confirms that advanced AI systems could, if not developed, deployed and operated with appropriate safeguards, oversight and security measures, pose catastrophic or existential risks to humanity, especially if set systems are misused, replicated, weaponized or allowed to operate with a high degree of autonomy. The concerns include the development of new generations of chemical and biological weapons and there have already been a flood of cybersecurity breaches involving AI agents operating autonomously. Cybersecurity experts have repeatedly warned that AI technology was being developed without the ability to protect humanity from possible future harms by the artificial intelligence. But Anthropic also says AI could profoundly accelerate the rate of progress in biology and medicine, potentially finding cures for things like cancer and Alzheimer's, and generating sustained acceleration in economic growth by boosting productivity. But AI is also supercharging cyberattacks by organized criminals and terrorist groups, as well as state actors in terrorism, like Iran, North Korea, China, and Russia. Those targets include utilities like power, water and telecommunications, government departments, hospitals, banking and superannuation systems, and businesses. Australia's Cyber Intelligence Agency's annual threat report cites some 1,500 security incidents in the year to June. That's an increase of 20%, and there have also been some 4,400 notifications of malicious or suspicious activity. That's an increase of 80%. A new study warns that the rates of hospitalizations for heart problems appear to be increasing at faster rates in American states that have legalized cannabis. Some U.S. states legalized the drug earlier than others in the 2010s, providing an opportunity for researchers to view how the changes in legislation may have impacted hospital data. Using more than 50 million hospital records from 2012 to 2018, the authors found the rate of admissions for heart failure increased by 4% in legal cannabis states compared to those that hadn't legalized it. The findings reported in the British Medical Journal also showed that heart attacks increased by 3% and abnormal heartbeat hospitalizations by over 2%. Scientists have confirmed that atmospheric greenhouse gas levels reached record highs last year, locking in further long-term global warming. The findings by the World Meteorological Organization show the average surface concentration of carbon dioxide in 2025 was 426.8 parts per million. That's a 153% increase over the 1750 pre-industrial baseline. Carbon dioxide levels rose by 2.8 parts per million during 2025, slightly smaller increase than the previous year, but substantial nevertheless. Concentrations of other greenhouse gases such as methane and nitrous oxide also rose to new records. Scientists say CO2 levels are now rising three times faster than during the 1960s, largely due to increases in fossil fuel burning. These rising greenhouse gases are trapping unprecedented amounts of heat, increasing the risks of extreme weather. The World Meteorological Organization says China remains the world's biggest carbon dioxide polluter, producing almost a third of the total global output, amounting to some 13.3 billion tonnes annually. That's almost three times more than the United States, which ranks second, and six times more than India, which is in third place. By comparison, Australia contributes roughly 1% or 387 million tonnes to global fossil fuel carbon emissions. Tehran says it's just built what it calls the father of all bombs, which the Islamic Republic says is the largest and most powerful conventional bomb it's ever made. The Islamic Revolutionary Guard says its new weapon is in response to the Pentagon's decision to consider using its GBU-43B Massive Ordnance Air Blast, or MOAB bomb, famously nicknamed the mother of all bombs, against Tehran's underground atomic bomb factories. Satellite images show that the Islamic Republic is working feverishly to rebuild these facilities in the wake of efforts by Washington and Jerusalem to destroy the terrorist regime's ability to continue its nuclear weapons program. The latest warnings come in the wake of evidence from ASIO, the Australian Security Intelligence Organization, that the Islamic Republic was behind two terrorist attacks in Australia over recent years, and it's now been revealed to have targeted several Australian journalists. A London cancer clinic run by a former ice cream salesman is claiming to be able to cure stage 4 cancer by soaking patients in oxidizing chlorine dioxide and industrial bleach. The skeptic's Tim Mendham says this pseudoscientific treatment doesn't work and it's actually very dangerous. Yeah, this is supposedly a place called Battersea Park Clinic, which is supposedly curing people, which is a dangerous thing to say. Stage four cancer, I believe they're talking about, which is pretty much the end of the line, in which they're putting people in a large plastic bag, their bodies like neck down, and then they're pumping in chlorine dioxide into that balloon sort of thing that's around their body. It's a bleach. It's an industrial bleach. The suggestion that the gas, the bleach, is causing oxidative stress to the cancer cell, altering its internal pH and forcing tumors to self-destruct. Believe it or not, there's no scientific evidence for this at all. It can be very harmful. The fellow who was running this thing as an ex-stockbroker, as a man who sold ice creams, became a holistic healer, obviously the best credential for medical treatment, and he admits it's dangerous. but there's a community out there who think bleach has all this sort of security powers. It's supposedly referred to as the bleacher community, and therefore they're really supportive of this thing. It's silly and it's dangerous. It's sort of like an idea someone thought of. It's a good idea to try putting a naked person in a plastic bag and pumping in. Sounds like a way to make money off desperate people, and at the same time you get to see them naked. LAUGHTER I don't know how transparent the plastic bag is. Anyway, this guy, the guy who runs it, is not answering a lot of questions, certainly not to people who are very sceptical of the system. It'll be one of those things that disappears again very quickly, unfortunately, along with the patients. That's the sceptic's timendum, and this is Space Time. And that's the show for now. Space Time is available every Monday, Wednesday and Friday through Bytes.com, SoundCloud, YouTube, your favorite podcast download provider and from spacetimewithstuartgarry.com. Space Time is also broadcast through the National Science Foundation on Science Zone Radio and on both iHeart Radio and TuneIn Radio. And you can help to support our show by visiting the Space Time store for a range of promotional merchandising goodies. or by becoming a Spacetime patron, which gives you access to triple-episode commercial-free versions of the show, as well as lots of bonus audio content which doesn't go to air, access to our exclusive Facebook group, and other rewards. Just go to spacetimewithstuartgary.com for full details. You've been listening to Spacetime with Stuart Gary. This has been another quality podcast production from Bytes.com.